1

Aust. J. Ed. Chem., 2006, 66,

ISSUE NUMBER 662006ISSN 1445-9698

Australian Journal ofEducation in Chemistrycation in Chemistry

CHEMICALEDUCATION

DIVISION

ROYAL AUSTRALIANCHEMICAL INSTITUTE

2

Aust. J. Ed. Chem., 2006, 66,

Introduction

The Australian Journal of Education in Chemistry publishes refereed articles contributing to education in Chemistry.Suitable topics for publication in the Journal will include aspects of chemistry content, technology in teaching chemistry,innovations in teaching and learning chemistry, research in chemistry education, laboratory experiments, chemistry ineveryday life, news and other relevant submissions.

Manuscripts are peer reviewed anonymously by at least two reviewers in addition to the Editors. These notes are a briefguide to contributors. Contributors should also refer to recent issues of the Journal and follow the presentation therein.

Articles

Articles should not exceed six pages in the printed formincluding tables illustrations and references - ca. 5000words for a text only document. Short, concisely writtenarticles are very welcome. Please use headings andsubheadings to give your article structure.

1. We prefer to handle all submissions electronically. Ourpreference is for Microsoft Word files in Mac format.However, you can send files from any commonWindows, DOS or Macintosh word processor.

2. On another separate page provide an abstract of 50 to100 words;

3. All photographs should be scanned and saved in JPEGformat.

4. All chemistry structures, and schemes should followthe guidelines set for ACS publications. It is preferredthat Schemes, Tables etc be arranged to fit in a column7 cm wide, although full page width will be accepted.

Guide for contributors to the Australian Journal of Education in Chemistry

Reference Styles

AusJEC reference styles are based on the most recentedition of the Publication Manual of the AmericanPsychological Association OR the Journal of ChemicalEducation.

Copyright

Your manuscript should not have been published alreadynor should it have been submitted for publicationelsewhere. If AusJEC publishes your manuscript then itwill become the copyright of the Royal AustralianChemical Institute. The RACI will, however, allow youto use the contents of your paper for most reasonable non-commercial purposes.

AusJEC Team

All manuscripts should be sent to Mauro MocerinoAusJEC Reviewing Panel

Vicky Barnett, AustraliaGlen Chittleborough, AustraliaDeborah Corrigan, AustraliaGeoffrey T. Crisp, AustraliaBette Davidowitz, South Africa

Onno de Jong, The NetherlandsKitty Drok, AustraliaLoretta L. Jones, USAFaan Jordaan, South AfricaScott Kable, AustraliaBob Morton, AustraliaMark Ogden, Australia

John Oversby, U.K.W (Bill). P. Palmer, AustraliaMarissa Rollnick, South AfricaJanet Scott, AustraliaRoy Tasker, AustraliaTony Wright, New ZealandBrian Yates, Australia

EditorsRobert Bucat,Chemistry, School of Biomedicaland Chemical Sciences,University of Western Australia,35 Stirling Highway, Crawley WA 6009, Australia.bucat@chem.uwa.edu.auPhone: (+61)(8) 9380 3158 • Fax: (+61)(8) 9380 3432

David TreagustScience and Mathematics Education Centre,Curtin University of Technology,GPO Box U1987, Perth WA 6845, Australia.D.Treagust@smec.curtin.edu.auPhone: (+61)(8) 9266 7924 • Fax: (+61)(8) 9266 2503

Mauro MocerinoDepartment of Applied Chemistry,Curtin University of Technology,GPO Box U1987, Perth WA 6845, Australia.m.mocerino@curtin.edu.auPhone (+61)(8) 9266 3125 • Fax (+61)(8) 9266 2300

Business ManagerSebastian Bunneyc/- Department of Applied ChemistryCurtin University of Technology,GPO Box U1987, Perth WA 6845, Australia.Email: sebastian.bunney@student.curtin.edu.auor: ausjec@yahoo.com.auFax (+61)(8) 9266 2300

3

Aust. J. Ed. Chem., 2006, 66,

In this issue ……….

RACI Chemical Education Division Standing Committee -Contact Details.

Kieran Lim, Chair, lim@deakin.edu.auSiegbert Schmid, Deputy Chair, siegbert@chem.usyd.edu.au,Rebecca Dalton, Secretary, R.Dalton@uws.edu.auMaree Baddock, Treasurer, m.baddock@exchange.curtin.edu.auMauro Mocerino, Immediate past Chair, m.mocerino@curtin.edu.auGreg Klease, Qld representative, g.klease@cqu.edu.auChris Brown, Qld Chemical Education Group Chair, c.l.brown@griffith.edu.auGeoff Salem, ACT Chemical Education Group Chair, geoff.salem@anu.edu.auAlan Arnold, ACT representative, a.arnold@anu.edu.auGeorgia Deretic, NSW Chemical Education Group Chair, deretic@hotmail.comMagdelena Wajrak, WA Chemical Education Group Chair, m.wajrak@ecu.edu.auBill Palmer, NT representative, bill.palmer@ntu.edu.auIan Mc Mahon, SA Chemical Education Group Chair, mcmahon@tsc.sa.edu.auGlen Chittleborough, SA representative, glench@senet.com.netBrian.Yates, Tas representative, Brian.Yates@utas.edu.auJudy Gordon, Vic Chemical Education Group Chair, judy.gordon@deakin.edu.au

Chemistry students are notoriously ‘turned off’ bytreatment of experimental errors and uncertainties, and thisfield provides a major challenge to university teachers.Brynn Hibbert describes a course of lectures based ondata analysis based on the three results of each of 26 teamsthat participated in a national high school titrationcompetition. The 78 results form an excellent data set,showing random and gross errors, that are used withMicrosoft Excel software to provide insight into plots,histograms, normal distributions (Rankit test), means,medians and standard deviations, robust estimators,hypothesis testing, and sources of measurementuncertainty. The approach seems designed to lend itself toappreciation of the questions “What does it mean?” and“Why is it so?” The principles are consolidated by couplingthe course with a practical course in which data analysisis expected.A most unusual chemical education research methodologyis described by Bill Palmer. He has investigated studentconceptions of the notions of chemical and physical changeby interpretation of their notes in laboratory manuals,purchased from book dealers and online sources, that wereused in the U.S.A. in the period 1890 to 1950. He looksfor ways of thinking that are parallel with alternativeconceptions (or misconceptions) identified by recentresearchers. Some of the problems associated with thisretrospective study of laboratory manuals are discussed.Obviously the method does not lend itself to defining inadvance specific concepts: one is limited to those conceptsthat students have chosen, or are required, to discuss. Thepaper has interesting insights into the changing nature ofteaching materials over the decades.Brown and Wylie describe a role model for otheruniversities in tackling the development of graduateattributes over and above chemistry subject knowledgeand technical skills. In a project at the University of New

England, the participants decided that priority should begiven to the attainment of outcomes associated withcommunication, social responsibility, information literacy,and problem solving. In each case, descriptors of threelevels of attainment were drawn up, and these mappedonto the curricula of all units involved in attainment of achemistry degree. Some deficiencies, due either to failureto incorporate or failure to document, have been exposedand repaired. Students and employers now have explicitstatements of the intention to concentrate on theseattributes, as well what skills they need to demonstrate.Demonstrations of effusion of gases are common.Petrusevski, Monkovic and Najdoski have developed ademonstration of effusion of a liquid which is easy toperform, not too slow, cheap, safe and free ofenvironmentally unfriendly products. When a porous cupfull of coloured glycerol is immersed in water, water entersthe cup slowly. This is attributed to faster effusion of watermolecules into the cup than of effusion of the heavierglycerol molecules out of the cup. The authors go to sometrouble to convince the reader that the phenomenon iseffusion, rather than osmosis. They also have a 44 s videoclip showing the phenomenon, taken by time-lapsephotography.Following an article in the previous issue discussing theorigins of chemical terms used to describe the macro levelof chemistry, Sarma here discusses the etymology of manyterms associated with the sub-microscopic level. Theseinclude terms used in the field of coordination chemistry,terms with the iso- or homo- and hetero- prefix, wordsused to describe the shapes and structures of molecules,terms prefaced by ortho-, para, meta-, pseudo-, eu-, a- oran-, and some common biochemical terms. She recognisesa potential tension between raising students to a level ofpleasure in knowing, and exposing to confusion due tochanges of meaning over time.

4

Aust. J. Ed. Chem., 2006, 66,

Editorial

Science in the frame

Do you get the feeling that the worm is turning and thatthe sciences are regaining respect and status in the generalpopulation? And that maybe chemistry student enrolmentsmight move northwards as a consequence?

Firstly, there is a good deal of rather high quality popularscience in the electronic and print media, and apparentlyit rates highly.

Then we had Professor Peter Doherty, a UQ graduate nowat the University of Melbourne sharing the 1996 NobelPrize in Physiology or Medicine “for their discoveriesconcerning the specificity of the cell-mediated immunedefence” and was subsequently named 1997 Australianof the Year. Not a sportsperson, diplomat, politician, orbusinessman!? Perhaps our 17-year-old new enrolees don’tknow much about him (they were only 7 when he won theNobel Prize), but their parents probably do, and he haspresented such a sensible and down-to-earth face in hispublic appearances. An ordinary person, communicatingwell, and obviously making a difference! By the way, hisacceptance speech (http://nobelprize.org/medicine/laureates/1996/doherty-lecture.pdf ) makes fascinatingreading about the processes of science.

More recently, Professor Barry Marshall and EmeritusProfessor Robin Warren with the NHMRC Helicobacterpylori Research Laboratory at the QEII Medical Centre atthe University of Western Australia have shared the 2005Nobel Prize in Physiology or Medicine “for their discoveryof the bacterium Helicobacter pylori and its role in gastritisand peptic ulcer disease.” The news coverage of thisextraordinary achievement has been considerable.

But this award was not even enough for either of theseachievers to be named the 2006 Australian of the Year.Beaten by a sportsperson, diplomat, politician, orbusinessman? No, another scientist – Professor Ian Frazerof the UQ Centre for Immunology and Cancer Research.Quoting the Australian of the Year website: “For 20 years

he has been researching the link between papilloma virusesand cancer, seeking ways to treat these viruses in order toreduce the incidence of cancer. Ian has now developedvaccines to prevent and to treat cervical cancer, whichaffects 500,000 women each year. A vaccine based on hisresearch has shown in worldwide trials to preventpapilloma virus infection and reduce Pap smearabnormalities by 90%. It has the potential to virtuallyeradicate cervical cancer within a generation.” Myanecdotal evidence is that many people are realising thepower of science, and are struck by how ‘ordinary’ (non-nerdish?) people like Doherty, Marshall and Frazer are.By the way, other scientists who have been Australians ofthe Year include Dr Fiona Wood (2005), Professor FionaStanley (2003), and Professor Sir Gustav Nossal (2000).Perhaps the status of science and scientists is better thanwe in the science fraternity have acknowledged. Maybethe doomsayers are within our own family, and we havetoo negative a perspective on where we are at?

Meanwhile, politicians are on the nose, people are gettingsick of corporate greed and corruption, and sometimes thelegal profession seems self-serving. There seems to beincreasing recognition that service industries, legalisticinterpretation and economics follow progress; they don’tdrive it.

So, the time is ripe to push home the advantage. We needto embed our science instruction in the context thatimproved quality (and duration) of life, can be achievedby the work of ordinary people engaged in scientificendeavour. We need to show that science is current, andcan make a difference. And although none of the scientistsabove are chemists, we need to demonstrate that many ofthem have made their advances through understandingsat the molecular level, and this is impossible without abase knowledge of chemistry.

RBB

The editors invite readers to make contributions to this Journal. As well as paperssubmitted for peer review, we welcome any of the following:

An invitation

• Short papers on chemistry topics orconcepts, from an educationalperspective

• Reflective papers teaching andlearning chemistry – general orspecific

• Letters to the editor

• Announcements

• Forthcoming events

• Books to review

• News about people or places

5

Aust. J. Ed. Chem., 2006, 66,

Teaching modern data analysis with The Royal Australian ChemicalInstitute’s titration competition

D Brynn Hibbert

School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia, b.hibbert@unsw.edu.au

AbstractThe Royal Australian Chemical Institute (RACI), the professional body for chemists in Australia, runs a yearly titrationcompetition for high school students. In 1997, twenty five teams of three students competed in a heat at the Universityof New South Wales, Sydney. The results are an excellent set of data, showing random and gross errors, that can beused to illustrate many basic aspects of data analysis, including histograms, normal distribution of data, means andstandard deviations, robust estimators, hypothesis tests and measurement uncertainty. They also support generalobservations that to of analytical results might not be fit for purpose, and provide a platform for a discussion of qualityin analytical chemistry.

Key Words: Data analysis, statistics, normal distribution, measurement uncertainty, acid base titration

1 IntroductionTeaching the statistics of data analysis to undergraduatestudents can be considered quite straight forward. Conceptssuch as mean and standard deviation might already befamiliar, and the formulae for confidence intervals, t-testsand the like are not the hardest to understand. With accessto spreadsheets, graphs and calculations have becomemuch easier. What students struggle with, in myexperience, is simply why they need to do data analysis,and what information is really being gleaned. Modernapproaches to metrology stress the ‘uncertainty approach’in which a holistic view is taken, rather than a classicalassignment of dispersion of results in terms of randomand systematic error (ISO, 2005). Laboratories that areaccredited to ISO 17025 (ISO, 1999) must estimatemeasurement uncertainty and must report it with theirresults when required by the client and when there iscomparison with a limit. A measurement result is a value(number plus unit) and an uncertainty, often expressed asan expanded uncertainty, which is a range in which thevalue of the measurand is expected to lie with a certainprobability (ISO, 1993).

This modern approach is an attempt to improve the qualityof analytical results, and in the author’s view, this has tostart as early as possible during the training of an analyticalchemist. There are a number of examples of the high costof poor analysis, and in recent years pronouncements fromnational institutes like NIST (National Institute ofStandards and Technology, USA) (May, 2001) and theLGC (Laboratory of the Government Chemist, UK) (King,1995) has implied that a surprisingly large fraction ofanalytical results are not fit for purpose. For example in asurvey of clients of analytical chemistry laboratoriescarried out in the early 1990s, the LGC found 29% ofrespondents reported results that did not meet the customerrequirements, and of these 12% caused ‘very serious loss’to the customer’s business (King, 1995).

Courses on data analysis, often a few lectures in ananalytical or physical chemistry subject, provide usefulexamples for their students to study, but these are often

chosen piecemeal with a specific illustrative objective foreach, and can lead to an incoherent whole. The datareported in this paper happens to have several usefulqualities that provide an exemplar for a good part of basicdata analysis. An advantage of the use of the data inAustralia is that many university chemistry students willhave taken part in the competition in their final year athigh school, and so feel some ownership and sympathywith the anonymous students, whose results are beingpicked over and analyzed. Here about 5 or 6 lectures in asecond year (of a three year BSc course) subject onanalytical chemistry is based on one set of results, fromthe RACI titration competition of 1997.

1.1 The RACI titration competitionEach year the RACI organizes around the states andterritories of Australia a titration competition, open tostudents attending high schools, usually in their last twoyears before tertiary education (grade 11 and 12). Winnersof regional heats go on to a final, and the whole competitionhas been a good instrument for raising awareness ofchemistry and the need for proper laboratory techniques.The model was the popular schools analysis competitionunder the auspices of the Royal Society of Chemistry, firstorganised in London by then Polytechnic of North London(now the London Metropolitan University) in 1982 (RSC,2005).

In the RACI competition teams of three are given (1) asodium hydroxide solution, (2) a hydrochloric acid solutionof assigned molarity, and (3) individual solutions of aceticacid. Common indicators are available, and glassware isprovided (although many students from private schoolscome with their own calibrated pipettes and burettes). Thestudents are expected to return the three amountconcentrations of the acetic acid solutions, and a markingscheme is used that usually adds the absolute error(|assigned value – student’s reported value|) of eachstudent, with the team with lowest aggregate being thewinner. The expected procedure is that each student willtitrate the hydrochloric acid solution with sodiumhydroxide and thus calculate the molarity of the sodium

14

13

6

Aust. J. Ed. Chem., 2006, 66,

hydroxide. Then with a suitable indicator (e.g. phenolphthalein) each will titrate the acetic acid with the, nowstandardized, sodium hydroxide and thus return therequired concentration of their acetic acid. It isrecommended that each student perform his or her ownset of titrations, although it is known that some teams pooltheir knowledge of the concentration of sodium hydroxide(and with occasional disastrous results).

2 The results of the 1997 UNSW heatTable 1 gives the results of the 26 teams that took part inthe 1997 heat held at the University of New South Wales,Sydney.

Table 1: Results of the analysis of three acetic acid solutionsAssigned values: A = 0.1147 M; B = 0.1241 M; C = 0.1340 M.

Solutionconcentration concentration concentration

Team of A (M) of B (M) of C (M)

1 0.1146 0.1242 0.1341 2 0.1148 0.1238 0.1343 3 0.1150 0.1241 0.1343 4 0.1150 0.1243 0.1336 5 0.1148 0.1247 0.1346 6 0.1139 0.1244 0.1336 7 0.1142 0.1244 0.1336 8 0.1144 0.1227 0.1339 9 0.1152 0.1245 0.132710 0.1155 0.1256 0.134511 0.1158 0.1252 0.135012 0.1143 0.1243 0.132313 0.1141 0.1255 0.133514 0.1153 0.1262 0.133615 0.1145 0.1231 0.131916 0.1177 0.1249 0.136017 0.1134 0.1246 0.130618 0.1144 0.1281 0.135219 0.1219 0.1299 0.141420 0.1138 0.0908 0.133021 0.1143 0.0855 0.132822 0.0920 0.0840 0.127823 0.1222 0.1212 0.085024 0.1556 0.1645 0.123125 0.0936 0.0854 0.081826 0.9083 0.8589 0.7746

Apart from the hapless teams 25 and 26 many of thestudents appear to have made a good attempt at theanalysis. When teaching with these data, I point out thattabulated values are not always easy to interpret and forman impression of the nature of the results. I also observethat out of 75 results only one person (team 3 B) actuallyreturned a value that was ‘correct’, and recall the famoussaying by Berzelius who is quoted as saying about analysis“…… not to obtain results that are absolutely exact – whichI consider only to be obtained by accident – but to approachas near accuracy as chemical analysis can go.”

2.1 Analysis of the data2.1.1 PlotsIt is always recommended to graph the data in some way.A simple plot against team number highlights the realproblem team (Figure 1a) , but also shows that one greatoutlier compresses the rest of the data.

Figure 1: Results of the RACI titration competition for sample B.Dashed line is the assigned value.

The data is sorted and the greatest point left out, nowshowing some more potential outliers (Figure 2). Homingin on the plot of Figure 3 shows the data that we candemonstrate (later) to be normally distributed. Students’attention must be drawn to the scales on the y-axes toemphasise the differences between the core data and theoutliers.

Figure 2: The data of Figure 1, ordered.

Figure 3: The data of Figure 1 with outliers removed.

7

Aust. J. Ed. Chem., 2006, 66,

2.1.2 HistogramA problem with displaying data using histograms, is thatunless there is a reasonable amount of data, they rarelylook convincingly normal. Here the 78 data have beenexpressed as a % error = 100 × (value – assigned value)/assigned value, to allow for the different assigned valuesand a histogram is shown in Figure 4. This results in twogroups, one of extreme values (the 21 in the ‘less’ and‘more’ categories) and the remaining majority which seemto cluster about the correct answer (i.e. error = 0).

Figure 4: A histogram of the errors of the results of Table 1. A barcontains values between the value shown for the previous binand its value, e.g. the bar labelled 0.5 counts results between 0and 0.5 %. The solid line is the normal distribution with mean0.01% and standard deviation 0.94 %.

2.1.3 RankitThere is not always time in a short course of data analysisto cover testing of data for normality, but the Rankit methodcan be quickly implemented in Excel and can provide aplatform for a discussion of distributions. The Rankitmethod is as follows, with each step creating data in anadjacent column.

1. Sort the data into ascending order. In Excel this is donevia a command in the Data menu, or icon on theStandard icon bar.

2. Write the cumulative frequency of the data, that is howmany data have values equal to or less than the rankedvalue. This definition means that ties get the higherrank. (data 7.1, 7.3, 7.3, 7.5 is ranked 1, 3, 3, 4) InExcel this becomes = COUNT($range) + 1 – RANK(cell, $range), where $range is the range of cellscontaining the ordered data with reference fixed toallow copying down the column (e.g. $A$1:$A$27),and cell is the cell containing the value to be ranked(e.g. A1).

3. Calculate the normalized cumulative frequency as f =cumulative frequency/n+1, where n is the number ofdata.

4. Calculate the point on the normal distributioncorresponding to the normalized cumulative frequency,z =NORMSINV(f)

5. Plot z against the data.

A straight line through f(z) = 0 indicates normality. Outliersare displaced to the left or right . Table 2 has exampleRankit calculations, and Figure 5 is the Rankit plot for allthe data. As before, team 26 distorts the plot, but byreducing the data set, data that gives a good straight lineindicating a normal distribution is easily found (Figures 6and 7).

Table 2. Rankit calculations for the 78 results of the titrationcompetition. Error = 100 × (result – assigned value)/assignedvalue. (The data is copied directly from an Excel spreadsheet andno precision of the values is implied).

Error (%) Rank z

-38.9552 1 -2.23654

-36.5672 2 -1.95458

-32.3127 3 -1.77469

-31.1845 4 -1.63875

… … …

32.55439 74 1.527719

35.65824 75 1.638748

478.0597 76 1.774688

592.1031 77 1.954577

691.8919 78 2.236538

Figure 5: Rankit plot for the 78 results of the titration competition

Figure 6: Rankit plot of the titration data without the highest 9and lowest 8 data

8

Aust. J. Ed. Chem., 2006, 66,

Figure 7: Rankit plot of the titration data with the ‘more’ and ‘less’data of the histogram of Figure 4 removed. The solid line is aTrendline generated by Excel.

As with the raw data, mention must be made of the x-axisscales of these plots. With this kind of data, an outlier testfor single outliers such as a Grubbs’ test, nowrecommended by ISO and IUPAC, or a Dixon’s Q-test,should not be used (Miller and Miller, 2000).

2.1.4 Means, medians and standard deviationsThe basic measures of a normal distribution are the mean(µ) and standard deviation (σ). Using our data we canestimate these parameters by the arithmetic average (x forN data)

and the sample standard deviation (s)

However these estimates are only valid if the data on whichthey are based are a random sample of normally distributeddata. The titration data illustrates the dangers of calculatingsample means and standard deviations before checkingfor outliers and normality. So-called ‘robust’ estimatorsare used when a data set is not perfectly normallydistributed to provide reasonable values for mean andstandard deviation. The median, which is the middle valueof data when they are arranged in order (or the average ofthe two middle values if there are an even number of data),is a robust estimator of the mean. A basis of the equivalentestimator of standard deviation is the interquartile rangeor IQR. The data is ordered and the median determined.Then the medians of each half of the data give the IQR.The IQR is thus the range of data containing the middle50% of the data. Calculation of the IQR requires sufficientdata to bin into quartiles, and so cannot be used on lessthan about one dozen data. As ± 1 standard deviationencompasses 68% of the data it is easy to show that theIQR × 0.75 is an estimate of the standard deviation. Thisis called the normalised interquartile range, or NIQR. Analternative robust estimator of the standard deviation, thenormalised median absolute deviation (NMAD), has beensupported by Miller and Miller (Miller and Miller, 2000)

Table 3: Statistics of the titration results for team member B.Assigned value = 0.1241␣ M. NIQR = interquartile range × 0.75,NMAD = median| x

i – median(x)| /0.68

statistic Data without greatest 4(unit) All data and least 4 valuesMean (M) 0.1486 0.1243 (assigned value 0.1241)

s (M) 0.1458 0.00114

median (M) 0.1244 0.1244

NIQR (M) 0.00161 0.00054

NMAD (M) 0.00169 0.00059

(1)

(2)

as a more useful robust estimate for small data sets. Themedian absolute deviation (MAD) is the median of theabsolute differences between each value and the medianof the data. Divided by 0.68 the MAD becomes thenormalised MAD (NMAD). Table 3 has the mean, median,standard deviation, NIQR and NMAD for the titration data.

Courtesy of team 26, the raw data is skewed high, as hasbeen seen, and the mean and standard deviation of theoriginal data does not give a useful estimate of the centreof the data nor the spread. The median and NIQR andNMAD for the whole data do return values that are inkeeping with the mean and standard deviation of thenormally distributed data. The message that goes with thesecalculations is that wherever possible data that can bedemonstrated to be normally distributed should beidentified and the sample mean and sample standarddeviation calculated. When this is not possible or desirable,and the data is known to have outliers or be skewed insome way, robust estimates of mean and standard deviationare to be used. An example is in interlaboratory trials whereeach result must be preserved and robust z-scores, z

i = [x

i

– median(x)]/NIQR , used (Hibbert, 2005). At this stageit is worth reminding students that all of these statisticshave the units of the measurand (here M), and that thesymbol for sample standard deviation is s, not sd, s.d.,SD, std dev, and so on.

2.2 Did the students get the right answer?If the course includes hypothesis testing then the data canbe used to answer the question, are the means of thestudents’ data significantly different from the assignedvalues? A Student-t test is used for each set of results (A,B, C).

with n – 1 degrees of freedom (1)

where ARV is the assigned reference value and x and s thesample mean and standard deviation of the normallydistributed data. The equation for the t value is written asin (1) in order to emphasize that t is just the differencebetween mean and assigned value expressed in standarddeviations of the mean. The null hypothesis, H

0, is that

the experimental data come from a population with meanµ = ARV. The t values from (1) may be compared with95% two-tailed t, generated in Excel by=TINV(0.05, n-1),or the probability associated with t calculated byP=TDIST(t, n – 1,2). This allows discussion of what is

9

Aust. J. Ed. Chem., 2006, 66,

being tested – not the probability of H0, but the probability

of the data given the truth of H0. Later a more formal

definition of P as the probability of finding a t value moreextreme than t in repeated experiments, can be giventogether with the knowledge that P is also the probabilityof making a Type I error if H

0 is rejected.

So the answer is clear, analysis of the solutions by teammembers who obtained results that were not classed asoutliers gave mean results that were consistent with comingfrom populations with the assigned values. (At this stagewe might lapse from statistical orthodoxy and suggest ‘theydid get the answer right’).

Table 4: Student-t tests on the means of the titration results

SolutionA B C

Assigned value /M 0.1147 0.1241 0.1340

mean /M 0.1146 0.1243 0.1338

s/M 0.0006 0.0011 0.0010

n 19 18 19standard deviationof the mean /M 0.00014 0.00027 0.00024t 0.7493 0.8058 0.7831

P(T>t) 0.4634 0.4315 0.4438

t0.05”,n-1

2.1009 2.1098 2.1009

A major change in our understanding of measurementresults has come with the rise of the field of ‘metrology inchemistry’. This has brought understanding ofmeasurement uncertainty as something more than a 95%confidence interval calculated from a few repeatedmeasurements. The ISO-approved method for estimatinguncertainty is given in the “Guide to the expression ofuncertainty in measurement” (ISO, 1993) and referred toby everyone as ‘the GUM’. A full GUM calculation is aserious business (as an example see (Saed Al-Deen,Hibbert et al., 2004)) but the principles of auditing whatfactors might contribute to the uncertainty of a result canbe instilled. The approach I have taken in my course is totry and predict the relative standard deviations of thestudents’ results which were, for the normally distributeddata, A: 0.0053, B: 0.0092, and C: 0.0077, i.e. between0.5 to 1 %. Also recorded with the results are the students’actual titration volumes. If the relative standard deviationsare averaged (as squared RSDs) over the top ten teams anestimate of the repeatability of a single titration as an RSDis 0.0033, or for a volume of 25 mL s

r = 0.083 mL.

Conventional wisdom has that the reproducibility(precision under conditions of changing analysts,equipment, reagents, time) is two to three times therepeatability (precision under conditions in which theexperiment is replicated by the same analyst with the sameequipment over a short period of time), and this is followedhere.

Approaches to estimating measurement uncertaintysuggest construction of a cause-and-effect diagram basedon the formulae used to calculate the result. A cause andeffect diagram, also called after its early protagonistIshikawa, or its fish-bone shape, is a way of displaying

and connecting information about a particular outcome.The amount concentration

(2)

(3)

where MNaOH

and MAcOH

are the molarities of sodiumhydroxide and acetic acid respectively and the V are thevolumes of the subscripted solutions. Most students keptthe sodium hydroxide in the burette and titrated first 25mL of the standard hydrochloric acid, and then 25 mL ofacetic acid. As the assigned molarity of the hydrochloricacid solution was 0.1068 M, the volumes of the titrationswould be around 25 mL, and the uncertainty estimationsneed only be done once for this volume.

A cause and effect diagram is evolved by considering firstequation 3 (figure 8), and then expanding M

NaOH in equation

2 (figure 9), and finally collecting all the precision termsto give the repeatability (figure 10).

Figure 8: Cause-and-effect diagram for the uncertainty of theconcentration of an acetic acid solution by titration

Figure 9: Cause-and-effect diagram for the uncertainty of theconcentration of an acetic acid solution by titration including theuncertainty of the sodium hydroxide solution.

10

Aust. J. Ed. Chem., 2006, 66,

Figure 10: Cause-and-effect diagram for the uncertainty of theconcentration of an acetic acid solution by titration with repeatabilitytreated separately.

In the GUM nomenclature, the repeatability of the resultsis a Type A uncertainty, while any estimates of other effects,such as the calibration of the pipettes, and burettes, errorsin estimating the end points and changes in temperatureare classed as Type B effects. It comes as a surprise tostudents that a 25 mL pipette might not deliver 25.00 mLeven when correctly filled to the mark. Few courses requirestudents to calibrate their glassware (as I recall doing inthe 1970s), so any calibration bias must be included in theuncertainty. The manufacturer gives the tolerance on a 25mL pipette as ± 0.03 mL, which taken as a rectangulardistribution leads to u = 0.03/√3 = 0.017 mL. Thetemperature effect can be calculated from an estimate ofthe temperature fluctuations in a laboratory. The studentsare told that the 95% confidence interval (i.e. ± 2 σ) onthe temperature in the laboratory was ± 3 °C, and thevolume coefficient of water is 0.00021 °C-1. Therefore u= 3 × 0.00021 × 25 × _ = 0.008 mL. These combine as

(4)

A similar calculation for the volume delivered by theburette has the tolerance ± 0.05 mL (u = 0.05/√3 = 0.029mL). The greatest uncertainty is in the estimation of theend point which after some discussion is agreed to be 0.1to 0.2 mL. If we take a rectangular distribution with a =0.15 mL, u = 0.15/√ 3 = 0.087 mL, and the combineduncertainty is

(5)

The relative uncertainty of the molarity of NaOH(Equation 2) is

(6)

where the uncertainty in the standard HCl is zero (we haveno information on this, and as everyone used the samesolution, any error will be as a bias in all results and not

contribute to the reproducibility.) Therefore

(7)

A similar calculation for the uncertainty of the molarity ofacetic acid is

(8)

A bright student might point out that the calibration errorof the burette should cancel between the two titrations.Although adding this component two times overestimatesthe uncertainty (Hibbert, 2003), the effect is not great andthis might be seen as an unnecessary complication. Therelative uncertainty of the molarity of the acetic acid isthus estimated to be 0.71%, which agrees well with therange of RSD% found for the teams. The process is veryinstructive for causing the students to think about sourcesof error, and it becomes clear that there are only two majorvariances, the repeatability and the end point uncertainty.Combining two repeatabilities for the two titrations andtwo end point errors gives:

(9)

which is a quick, and entirely appropriate estimate. Themoral is that if you are trying to reduce the uncertainty ofan analysis, it is only worth tackling the one or two greatestsources.

4 DiscussionAs has been shown, the data from this competition is anideal pedagogical tool for introducing nearly all theimportant concepts in statistical data analysis. (In mycourse only calibration is not touched by these data). Apartfrom being used to teach the manipulations of data usinga spreadsheet such as Excel, the results can be used as abasis for discussions about the practice of analyticalchemistry. Why were 23 of the 78 or 29% (accidentallythe same as the LGC figure) outside a reasonable estimateof the uncertainty? Why does this appear to fit in with the

to findings of NIST and the LGC? Some of the moreerrant values, as found in the wider studies are not chemicalerrors, but misplaced decimal points, or transcriptionerrors, but as I say to the students there is no help in apathologist explaining to grieving relatives that the dosagerecommended was right, except that it was ten times toomuch!

The nature of random error can be discussed. What is the‘bell shaped curve’ of figure 4 telling us? If the competitionwere held a week later, we would expect the samedistribution of results (this is the raison d’etre of statistics),

14

13

11

Aust. J. Ed. Chem., 2006, 66,

but would the same teams be best and worst? In otherwords, is the distribution one of abilities in titration, or isit a random measurement uncertainty on the day? If it isthe latter, should all the teams who are within the expectedmeasurement uncertainty receive a prize, as the team thathappens to have the best score on the day could findthemselves less well placed another time?

With a reproducibility of less than 0.5 %, even in the handsof relatively unskilled chemists, a titration is still one ofthe most accurate analytical methods. The results aretraceable to the international system of units (SI) ifappropriately traceable standard solutions are used.Someone might ask how we know the assigned values arecorrect? This is a good question, as they are determinedby repeat titrations by the organisers of the competition,who might be expected to provide accurate results, butthey do not go to much greater lengths than the competitorsand do not provide uncertainty statements. As the judges’answer is final, this is a good example of assigned valuesrather than demonstrably traceable results. However, thegood agreement between the consensus means and theassigned values suggest they are not too far out.

5 ConclusionsHigh School titration and analysis competitions have beengood ambassadors for chemistry and their usefulness canbe extended to university courses. Data from the 1997RACI competition round held at the University of NewSouth Wales has provided a complete environment forteaching modern data analysis. Students who have beenexposed to this approach since 2000, have shown a greatermotivation in wanting to understand what the data andtheir interpretation means. The impact of the approach isaugmented when coupled with a practical course for which

uncertainties have to be estimated, and towards the end ofthe session, results are analysed in a similar manner. Finallythe importance of quality analytical measurements isstressed, hopefully giving students a proper attitude to theirwork when they join the workforce.

AcknowledgmentsThe author gratefully thanks Dr Peter Chia, who organizedthe RACI competition at UNSW in 1997, for allowinghim to use and publish the data.

ReferencesHibbert, D. (2005), Interlaboratory Studies, Encyclopedia of AnalyticalScience, eds. P. J. Worsfold, A. Townshend and C. F. Poole, Oxford,Elsevier 7: 449-57.

Hibbert, D. B. (2003), The measurement uncertainty of ratios whichshare uncertainty components in numerator and denominator,Accreditation and Quality Assurance, 8: 195-199.

ISO (1993), Guide to the Expression of Uncertainty in Measurement,Geneva, Switzerland, ISO.

ISO (1999), ISO 17025 General requirements for the competence oftesting laboratories, Geneva, Switzerland, ISO.

ISO (2005), International vocabulary of basic and general terms inmetrology, Geneva, Switzerland, ISO.

King, B. (1995), Quality in the Analytical Laboratory, Quality Assuranceand TQM for Analytical Laboratories, ed. M. Parkany, Cambridge, TheRoyal Society of Chemistry: 8 - 18.

May, W. (2001), E-Health and Technology: Empowering Consumers ina Simpler, More Cost Effective Health Care System, NIST, Gaithersberg,http://www.nist.gov/testimony/2001/wmehealt.htm.

Miller, J. N. and J. C. Miller (2005), Statistics and Chemometrics forAnalytical Chemistry, 5th edition, Pearson Education Ltd., Harlow.

RSC (2005), Schools Analytical Competition, Royal Society ofChemistry, Cambridge, http://www.rsc.org/lap/rsccom/dab/adcomps.htm.

Saed Al-Deen, T., D. B. Hibbert, et al. (2004), An uncertainty budget forthe determination of the purity of glyphosate by quantitative nuclearmagnetic resonance (QNMR) spectroscopy, Accreditation and QualityAssurance, 9 (1-2): 55 - 63.

19thInternational Conferenceon Chemical Education

August 12 - 17 2006Seoul, KOREA

Theme: Chemistry and Chemical Education for Humanity

http://www.19icce.org/19thICCE/19ICCEindex.html

12

Aust. J. Ed. Chem., 2006, 66,

Children’s alternative conceptions of physical and chemical changeobtained from historical sources compared with those found in otherrecent studies

Bill Palmer

Faculty of EHS, Charles Darwin University, Darwin, Australia, bill.palmer@cdu.edu.au

AbstractThis paper extends the author’s previous studies on student alternative conceptions as found in the written work recordedin students’ experimental chemistry manuals from the United States of America between 1890 and 1950. The methodologyand some of the theoretical problems of this type of research will be discussed. The purpose of this study is to show thatalternative conceptions held by students and recorded in their own writing can be investigated historically from studentmanuals.

The practical manual during the period 1890 to1950: an introductionFrom the literature there appear to be no previous studiesthat examine student alternative conceptions historically.However, the literature does support the claim that thereis some geographical and cross-cultural consistency instudent alternative conceptions (Wandersee, Mintzes, &Novak, 1994, pp. 185-186).

This study attempts to find common alternativeconceptions (referred to as misconceptions in some studies)about physical and chemical change in students’ ownwritten work as recorded in their experimental chemistrymanuals in the United States of America between 1890and 1950 and compares the results with the results reportedin more recent studies. The study thus trials a methodologyfor showing that alternative conceptions held by studentscan be investigated historically using student manuals.There are obvious methodological problems. For example,a number of different texts using different experimentsare used in this study. The question here is whether thematerials provided for student learning were sufficientlysimilar in all cases for there to have been a commonlearning experience. This may be an issue, but a numberof well-regarded studies, such as international studies havenot thought it to be an essential prerequisite. A furtherproblem lies in assessing whether each piece of workrepresents the original thought of each individual studentand was not, for example, merely copied from theblackboard. This cannot be proven, but the idiosyncraticnature of the writing often provides a high degree ofprobability that the student work analysed was original.

An earlier study (Palmer, 2003) gives considerable detailabout the practical laboratory manual (Stevens, 1895)which had been completed by a student called CarrieSouthard, a junior at Columbus North High School,Columbus, Ohio, during 1896. Careful reading of her workindicated that it would be possible to say something abouther ideas on physical and chemical change. The two factorsthat allowed that conclusion were the very open-endedorganisation of the practical laboratory manual and the

exceptionally thorough way in which the manual wascompleted by the student. This is an example of goodteaching and good learning from 1896. The amount ofwork done by the student is itself surprising. The student(Carrie Southard) completed one hundred and thirty oneexperiments in one year, starting in September 1896, andfinishing in April 1897. (The last few experiments are notdated or numbered.) The style is certainly that of a studentwriting and not of a teacher’s dictated notes. Nonetheless,one cannot be certain that the notes are entirely her ownthoughts as the teacher may have given some advice thatwas copied down. What is noticeable is that the variety ofexperiments performed improved her facility withscientific language and also with scientific concepts. Theconcept of chemical change is continually reinforcedthroughout the year, though there is little or no use of theconcept of physical change.

Methodology: analysing other students’ workOther student work was obtained so that conclusions couldbe drawn more widely. Over a period of two yearslaboratory manuals were purchased from book dealersusing a site (Bookfinders, 2004), which claims 15,000book dealers with 15 million books, and also by biddingfor books in Ebay auctions (Ebay, 2004). This has certainlybeen a learning experience. Any writing by students inbooks is seen as a grave disadvantage by dealers who lookfor books in a pristine state. The book dealers’ web-pagesneeded thorough searching at regular intervals, followedup with e-mails asking for further information. Ebay hasdelivered quite good results, but in general out of the fivehundred antiquarian chemistry books offered a week, onlyone or two suitable manuals are likely to be available.

The books most likely to contain student’s work are calledchemistry ‘laboratory manuals’, though other terms suchas ‘laboratory exercises’ are sometimes used. In general,these contain details of the experiment to be attempted onthe left hand page of the manual and a blank right handpage on which the student can enter experimental results.These books are generally not very imaginative, but theydeveloped over time.

13

Aust. J. Ed. Chem., 2006, 66,

A history of practical manualsThe earliest practical manuals were probably alchemicalrecipe books. Later there are texts from the early 19thcentury (Henry, 1817) that emphasise the practical natureof chemistry, but they also contain much theory. After the1860s there is a greater variety of books emphasisingpractical chemistry, some for special groups such asmedical students (Odling, 1869) or agricultural students(Coleman & Addyman, 1893) and some for thosebeginning chemistry (Appleton, 1878; Ripper, 1885;Stockhardt & Heaton, 1887). It is perhaps from this lattergroup that chemistry laboratory manuals developed.

French (1886) appears to be a transitional example,consisting of many experiments in the traditional threecolumn format (experiment, observation, conclusion) withthe first column printed and the subsequent columns beingcompleted by the student. The problem with this type ofpractical manual (at least in this case) is that there seemsto be no theoretical input.

Well known American authors such as Williams, Dennisand Clark, Remsen, McPherson and Henderson, Newelland Brownlee, Fuller, Hancock, Sohon, and Whitsitproduced successful school chemistry texts. Hessler andSmith (1902, ii, preface) date school chemistry laboratoriesin the USA from the 1880s with a consequent increase inschool textbooks and laboratory manuals following soonafter. Hessler and Smith (1902) may be in error, as thereare earlier manuals such as those by Hinrichs (1870; 1871).Initially by popular demand and then as a matter of course,chemistry laboratory manuals were produced toaccompany the new textbooks. Hessler and Smith (1902)detail the common laboratory manual faults which theirmanual is claimed to avoid. They did this by producinglaboratory exercises (a miniature manual) at the back oftheir textbook and sold the whole as a single book. Theyalso provided a handbook for teachers. However their ideasdid not achieve general favour, though a few authorscontinued this practice (Rosenholtz, 1932).

Generally teachers or schools chose the textbook thatstudents would use. Teachers found that they could usethe adopted textbook in theory lessons and itsaccompanying laboratory manual in practical lessons. Bythe numbers of these old books still available, they musthave achieved great popularity in the USA, but strangelythey never seem to have been very popular in the UnitedKingdom or elsewhere. All the actual examples ofchemistry laboratory manuals containing student writingseen by the author are from the USA. The usage generallyinvolved students completing the blank pages or blankspaces in pencil. In some schools these pencilled answerswere erased at the end of the year and the books used again.In the United Kingdom, the general practice was to havebooks which contained theory and practical work together,or alternatively separate practical books, but in either casestudents used to write up their experiments in blank notebooks. Such student note books do not appear to have beensaved, though some limited information can be foundonline (The Science Teacher Festival in 2001). The UnitedKingdom also had a tendency to have more chemistry

practical books that were associated with qualitativeanalysis.

The great majority of textbooks of this period contain asection on physical and chemical change, so the majorityof accompanying laboratory manuals contain anexperiment on physical and chemical change or anexperiment on mixtures and compounds. This will be anessential feature for the manuals to be analysed. Manualsshould also have considerable student practical workwritten up. Analysis will be limited to manuals printedprior to 1950.

From the manuals actually obtained, the most commonand thus the most popular, seems to have been Brownlee,Fuller, Hancock, Sohon and Whitsit (1921a; 1921b) thoughthey had slightly different manuals for their differentbooks. The other very popular manual was McPhersonand Henderson (1921). Both these books lasted, withrevisions, from the 1900s to the 1930s and Brownlee,Fuller, Hancock, Sohon and Whitsit was certainly still inprint in 1956. In this small sample Dennis and Clark (1902)also seems to have been a popular early manual. Othermanuals were also used but varied in popularity over theperiod. Some authors, such as Williams (1896a; 1896b),produced two different manuals, one for general chemistryand one for inorganic chemistry.

The research on alternative conceptions on physicaland chemical change.What does current alternative conceptions literature sayabout student understanding of physical and chemicalchanges? A number of studies have been carried out onphysical and chemical changes over the past twenty years.Each has identified common alternative conceptions, butthe alternative conceptions identified vary dependant onthe study. Some typical results from a variety of studiesare provided below..

STUDY 1 Anderson & Renstrom (1982). In thisexperiment steel wool was burned whilst on a balance.The researchers asked 593 pupils to describe what theyhad seen. The answers were a mixture of observations andexplanations. Anderson and Renstrom (1982) divided theseanswers into five categories which are: no explanation;expressions indicating that the steel wool became lighter;explanations of a physical nature; explanations of achemical nature; other. This is a limited set of criteria, butis comparatively simple.

STUDY 2 Schollum (1982) notes the following alternativeconceptions about chemical change in his study (inAnderson, 1984).

a. The conglomerate conception. All the substances thatreact collect together like needles to a magnet.

b. The conception of ‘favourable circumstances or (Bearin a Cave)’. The products of chemical reactions havebeen there all the time, though hidden, but whenconditions are right they appear.

c. Magic: Anything can happen in chemistry.

STUDY 3 Briggs & Holding (1986 in Griffiths, 1994)noted that the students’ ideas were often difficult to assess

14

Aust. J. Ed. Chem., 2006, 66,

as they had not been asked specifically to provide theirreasoning. However, the following unacceptable ideaswere noted:

a. Mass is not conserved in a chemical reaction.b. Melting is evidence of a chemical change.c. Expansion of a substance on heating is evidence of a

chemical change.d. Change of colour is evidence of a chemical change.e. Change in the form a substance is evidence of a

chemical change.f. When elements combine to form a particular

compound, they may do so in different proportions.

STUDY 4 Hesse & Anderson (1992) Three alternativeconceptions were inferred from the discussion in a paper(in Griffiths, 1994.)

a. Conservation of matter applies to solids and liquids,but may be ignored for gaseous reactants and products.

b. It is not necessary to compare the combined mass ofall reactants with that of all products when consideringconservation of matter.

c. The characteristics which represent a change asphysical are also appropriate when consideringchemical change.

STUDY 5 Anderson (1991) and Pfundt (1981) in separatepapers came to the following conclusions about commonalternative conceptions on physical and chemical change(in Driver et al, 1994, p. 86).a. No conception other than ‘it just happens like that:

matter just disappears: when petrol is used as a fuel ‘itjust vanishes’;

b. Product materials, though unseen, must somehow becontained in the starting materials (for example, somethink that the water which results from the distillationof wood must already have existed as such in wood);

c. The product material is just a modified form of thestarting material: ‘as the alcohol burns it turns intoalcohol vapour’;

d. The starting material undergoes transmutation to theproduct material: ‘the steel wool that burnt has turnedinto carbon’;

e. Starting materials interact and form a different product:‘oxygen reacts with copper and forms copper oxide’.

STUDY 6 Griffiths (1994) examined a number of theearlier papers and put together the conclusions that theyhad reached. The resultant is the following list of eighteenalternative conceptions relating to physical and chemicalchange.

a. Changes involving natural phenomena are physical,while changes involving artificial phenomena arechemical.

b. When matter changes in appearance a chemical changeis involved.

c. When one substance is added to another any observedchange is chemical, whereas if only one substance isinvolved any observed change is physical.

d. Changes which can be reversed are physical changes,whereas changes which cannot be reversed arechemical changes.

e. Conservation of matter applies to solids and liquids,but may be ignored for gaseous reactants and products.

f. It is not necessary to compare the combined mass ofall reactants with that of all products when consideringconservation of matter.

g. The characteristics which represent a change asphysical are also appropriate when consideringchemical change.

h. Mass is not conserved in a chemical reaction.

i. Melting is evidence of a chemical change.

j. Expansion of a substance on heating is evidence of achemical change.

k. Change in the form of a substance is evidence of achemical change.

l. Change of colour is evidence of a chemical change.

m. When elements combine to form a particularcompound they may do so in different proportions.

n. Matter may be destroyed in a chemical reaction.

o. Substances can change their properties, and still retaintheir identity.

p. Boiling and dissolving are chemical changes.

q. Reaction products are hidden in a substance, andemerge when conditions are right.

r. Reactions can occur by magic …anything can happenonce chemicals set each other off.

A preliminary analysis of some chemical laboratorymanuals.Appendix 1 lists the thirty-nine chemical laboratorymanuals that were available. In order to analyse studentlearning, the student needs to have written somethingrelevant in the manual under the section on physical andchemical change or on the section on mixtures andcompounds. Although manuals vary, one or other of thesesections or both need to be present. Twenty-four of thethirty-nine manuals were excluded, some because theycontained no student comments, and others becausestudents had not commented in the section on physicaland chemical change or in the section on mixtures andcompounds.

Of the thirty-nine manuals observed, only fifteen couldbe analysed in terms of student learning. The manuals ornotes (see Appendix 1) that could be examined weremanuals numbers 5, 8, 9, 10, 11, 12 16, 18, 22, 23, 26, 27,29, 32 and 34.

Initially the simplest method for categorising the fifteenmanuals was chosen. The vast majority of the content ofthese manuals is student observation with only smallamounts of explanation. It is possible that some of theobservations which the students have made are incorrect,but this does not amount to a alternative conception. It isin the explanatory part of the results that alternativeconceptions may be found. The four initial categories are:

15

Aust. J. Ed. Chem., 2006, 66,

no explanation; explanations of a physical nature;explanations of a chemical nature; other. These categoriesare for experiments about physical and chemical changeseparately to those for mixtures and compounds. Ananalysis of student alternative conceptions about physicaland chemical change may be found in Appendix 2Aconsidered where possible under the four categories statedabove. The table of student alternative conceptions aboutmixtures and compounds may be found in Appendix 2B.

The results of the search for student alternative conceptionsare very limited for a variety of reasons. Firstly, the authorsof manuals often only ask students to carry out experimentsand make observations. Secondly, where they do askstudents questions that demand explanations, the studentsoften omit those explanations. In either case, since it isonly explanations that offer fertile ground for findingstudent alternative conceptions, it is unlikely that manymanuals will contain evidence of student alternativeconceptions. Lastly, of the thirty-nine manuals containingstudent writing of some sort, only two appeared to havebeen marked by teachers. It might be thought that studentsmay take less care in completing their work if teachers donot check it thoroughly. Appendix 2A and 2B list the detailsof the fifteen manuals available under the four categories.Only numbers 8, 9, 10, 11 & 34 yielded alternativeconceptions. Student Number 8 was Carrie Southard,whose work was discussed earlier.

Alta Lemmon: Student Number 9Student Number 9 was Alta Lemmon from Carthage,Indiana. She carried out experiments on Section 4(Williams, 1896a) taken from the manual, Laboratorymanual of general chemistry, entitled ‘The molecular state’which involved dissolving sugar in water, filtering thesolution and tasting the filtrate. The experiments areperformed and no explanation is required. In Section 5(Williams, 1896a), part of the filtrate has been kept fromSection 4 and sulphuric acid is added. A black colour wasobserved, though several observations requested in the textwere omitted. The text asks if the phenomenon was aphysical and chemical change. Alta correctly states it tobe a chemical change, but is in error when she says that‘The sulphuric acid destroyed the atoms of sugar’.

Is this just a careless statement or does it really indicatefundamental misunderstandings about the nature ofchemical change? One might believe it was justcarelessness, but in Section 6 (Williams, 1896a) in thetraditional experiment heating copper and sulphur, Altawrites:

…and found both the brimstone and Cu turningsturned to CuS. This shows that an atom of Sunited with an atom of Cu to form an atom ofCuS. (Alta Lemmon)

It would seem that this hard working student (shecompletes most of the manual) has problems inunderstanding the differences between atoms andmolecules and this gives doubts as to whether her conceptsof physical and chemical change or mixtures andcompounds are clear either. However at the end of

experiment one hundred she is writing in a fuller and moreconfident style.

Eric Austin: Student Number 10Student 10 is Eric Austin who used another of the manualsby Williams called Laboratory manual of inorganicchemistry (Williams, 1896b). Eric completed a highproportion of this manual. In this case, Section 9 is entitled‘The physical division of matter’ which also involveddissolving sugar in water, filtering the solution and tastingthe filtrate. Eric’s observations are confused. He considersthat the sugar water has changed to water on filtering thesolution, which he calls a chemical change rather than aphysical change. Section 10 is entitled ‘The chemicaldivision of matter’ and is the dehydration of sugar, whichEric correctly concludes is a chemical change, though thereasoning is faulty. He said (spelling corrected):

After you put the sugar into an e.d. [evaporatingdish] and heating them it all dissolves and leavesC

12H

22O

11 -black-it has no odour-it is a chemical

change-because it all dissolves but the charcoal.The acid makes it warm.

Eric appears to have had his own alternative conceptionsof physical and chemical change which are difficult tocategorise.

Ralph C Zindel: Student Number 11In the traditional experiment with iron and sulphur relatingto mixtures and compounds, Ralph Zindel (Dennis &Clarke, 1902, p. 13) writes:

When the mixture is heated the substances [ironand sulphur] unite and form a metal. A chemical[change] takes place… (Ralph Zindel)

Presumably Ralph Zindel has just made a careless error inusing the word ‘metal’, because he describes the newsubstance as a compound in the next sentence.

Anna L Ficerchia: Number 34The final possible student alternative conception wasnumber 34 (Anna L Ficerchia) but this student has madean error of observation when adding dilute hydrochloricacid to the new substance formed by heating iron andsulphur. She observed that the gas produced was odourlessand concluded that the gas was hydrogen, whereas theexpected result would have been that the gas was the foul-smelling hydrogen sulphide. It would seem that in thiscase the student did not have an alternative conceptionoriginally, but may well have been led to one as a result ofincorrect observation.

Summarising the results of analysing the manualsThe results of the observations of manuals for studentsnumbers 8, 9, 10, 11 & 34 were compared with thecollection of modern alternative conceptions as reportedby Griffiths (1994), (see study 6). There is insufficientevidence to classify students 8, 11 & 34 as having somespecific alternative conception. However student 9 failsto distinguish correctly between atoms and molecules ontwo occasions and this is a commonly identified problemin the literature (Alamina, 1992, p. 201). Student 10

16

Aust. J. Ed. Chem., 2006, 66,

appears to believe that sugar dissolving in water is achemical change, which is a common alternativeconception (see criterion 16 in Griffiths, 1994).

Overall the method was extremely interesting to trial andit has yielded limited though promising results. Perhapsonly ten per cent of manuals will produce any significantresults, but it is clear that there are alternative conceptionsin student work from the past identical with studentalternative conceptions of today. This previously untriedmethod could, in the future, be used with greater numbersof manuals to investigate historical alternative conceptionsrelated to physical and chemical change more thoroughly.It also opens the way for investigation of any other topiccommonly found in student manuals.

ReferencesPlease note that the full references to the following laboratory manualsreferred to in the study can be found in Appendix 1: Appleton, 1878;Coleman & Addyman, 1893; French, 1886; Henry, 1817; Hessler &Smith, 1902; Odling, 1869; Ripper, 1885; Rosenholtz, 1932; Stockhardt& Heaton, 1887.

Alamina, J. I. (1992). Secondary school pupil’s understanding of chemicalchange with particular reference to burning and precipitation, PhDDoctoral thesis. Leeds: The University of Leeds, School of Education.

Anderson, B. & Renstrom, L. (1982). Oxidation of steel wool: EKNAReport No 7. Molndal, Sweden: Gotenburg University.

Anderson, B. (1984). Chemical reactions: EKNA Report No 12. Molndal,Sweeden: Gotenburg University.

Anderson, B. (1991). Pupils’ conceptions of matter and its transformations(age 12 -16), Studies in Science Education, 18, 53-85.

Bookfinders (Accessed 20/2/05)at URL http://www.bookfinder.com/

Briggs, H. & Holding, B. (1986). Aspects of Secondary Students’Understanding of elementary Ideas in Chemistry. Leeds: University ofLeeds. (in Griffiths, A. K. 1994.)

Brownlee, R. B., Fuller, R. W., Hancock, W. J., Sohon, M. D. & Whitsit,J. (1921a). Laboratory exercises to accompany ‘First principles ofchemistry’ New York: Allyn & Bacon.

Brownlee, R. B., Fuller, R. W., Hancock, W. J., Sohon, M. D. & Whitsit,J. (1921b). Laboratory exercises to accompany ‘Elementary principlesof chemistry’ (Ring bound sheets) New York: Allyn & Bacon.

Dennis, L. M. & Clark, F. W. (1902). Laboratory manual to accompanyClark and Dennis’s elementary chemistry (Student Ralph C. Zindel).New York, Cincinnati, Chicago: American Book Company.

Ebay (Accessed 2/1/04) at URL http://www.ebay.com/

Griffiths, A. K. (1994). A critical analysis and synthesis of research onstudents’ chemistry misconceptions in Hans-Jurgen Schmidt (editor),Problem solving and misconceptions in chemistry and physics (1994International seminar). Dortmund, Germany: ICASE.

Hesse, J. I. & Anderson, C. W. (1992). Students’ conceptions of chemicalchange. Journal of Research in Science Teaching, 29 (3), 27-299 (inGriffiths, 1994).

Hinrichs, G. (1870). The elements of physics demonstrated by the student’sown experiments with a plate and a journal of experiments. Davenport,Iowa: Griggs, Watson, & Day.

Hinrichs, G. (1871). The elements of chemistry & mineralogy,demonstrated by the student’s own experiments with a plate and a journalof experiments. Davenport, Iowa: Griggs, Watson, & Day.

Palmer, W. P. (2003). A study of teaching and learning about theparadoxical concept of physical and chemical change. UnpublishedDoctoral Thesis, Science and Mathematics Education Centre, CurtinUniversity of Technology, Perth, Australia. Now online at http://adt.curtin.edu.au/theses/available/adt-WCU20040112.095648/

Pfundt, H. (1981). Pre-instructional conceptions about substances andtransformations of substances in Jung, W., Pfundt, H. and von Rhoneck,C. (editors) Proceedings on the international workshop on problemsconcerning students’ representation of physics and chemistry knowledge,14-16 September, Pedagogische Hochschule, Ludwigsburg, pp 320-341.(in Driver, Squires, A., Rushworth, P. and Wood-Robinson, V., 1994,p.86).

Schollum, B. (1982). Chemical change, New Zealand Science Teacher,33, 5-9.

The Science Teacher Festival in 2001 (Accessed 20 February 2005)

http://www.shu.ac.uk/schools/ed/stf/pupilswork/framesets/photosof.

Stevens, F. L. (1895). The Columbus chemistry note book, (ColumbusNorth High School, copyright by F.L. Stevens).

Wandersee, J. H., Mintzes, J. J. & Novak, J. D (1994) Research on

alternative conceptions in science (Chapter 5) pp. 177-210. Handbookof research on science teaching and learning (edited by Dorothy L.Gabel). New York & Toronto: Macmillan.

Williams, R. P. (1896a). Laboratory manual of general chemistry. Boston:Ginn & Company, Publishers.

Williams, R. P. (1896b). Laboratory manual of inorganic chemistry.Boston: Ginn & Company, Publishers.

Appendix 1Practical Laboratory manuals collected, displayed in chronological order, including the names of students who owned them

Chemistry

1 1817 Henry, W. The elements of experimental chemistry to which are added notes by John Redman Coxe (Fourth Americanfrom the seventh London edition). Philadelphia: James Webster.

2 1869 Odling, W. A course of practical chemistry, arranged for the use of medical student (fourth edition). London: Longmans,Green and Co.

3 1878 Appleton, J. H. The Young Chemist: a book of laboratory work for beginners. Philadelphia.4 1885 Ripper, W. Practical chemistry with notes and questions on theoretical chemistry adapted to the revised syllabus of the

Science and Art Department for the elementary stage of inorganic chemistry. London: Wm. Ibister, Limited.5 1886 French, N. Experiment blanks for a short course in elementary chemistry (Student: Anon 1).Boston: M. T. Rodgers &

Co.(photocopy).6 1887 (1E 1871) Stockhardt, J. A. & Heaton, C. W. Experimental chemistry: A handbook for the study of the science by simple

experiments. London: George Bell & Sons.7 1893 Coleman. J. B. & Addyman, F. T. Practical agricultural chemistry for elementary students. London: Longmans, Green &

Co.8 1896 Stevens, F. L. The Columbus chemistry note book, (Columbus North High School, copyright by F.L. Stevens, 1895).(Student:

Carrie Southard, Junior at Columbus North High School, Columbus, Ohio in 1896).9 1896a Williams, R. P. Laboratory manual of general chemistry (Student Alta Lemmon). Boston: Ginn & Company, Publishers.10 1896b Williams, R. P. Laboratory manual of inorganic chemistry (Student Eric Austin). Boston: Ginn & Company, Publishers.11 1902 Dennis, L. M. & Clark, F. W. Laboratory manual to accompany Clark and Dennis’s elementary chemistry (Student Ralph

C. Zindel). New York, Cincinnati, Chicago: American Book Company.

17

Aust. J. Ed. Chem., 2006, 66,

12 1902 Dennis, L. M. & Clark, F. W. Laboratory manual to accompany Clark and Dennis’s elementary chemistry (Student A. B.Nilliv). New York, Cincinnati, Chicago: American Book Company.

13 1902 Hessler, J. C. & Smith, A. L. Essentials of chemistry (with laboratory manual). Boston: Benj. H. Sanborn & Co.14 1903 Tilden, W. A. Practical chemistry: the principles of qualitative analysis. London: Longmans, Green & Co.15 1905 Remsen, I. A laboratory manual containing directions for a course of experiments in general chemistry, systematically

arranged to accompany the author’s “Elements of chemistry” (Student: Alex W . Spears). New York: Henry Holt & Co.16 1910 Roe, J. N. Practical chemistry (Student: Anon 1). Valparaiso: M. E. Bogarte Book Co.17 1912 Blanchard, J. M. Household chemistry for girls: a laboratory guide. New York: Allyn and Bacon.18 1913-1914 Junior chemistry (Notes by student: Lillian Abra Rhodes)19 1915 McPherson, W & Henderson, W. E. Laboratory manual arranged to accompany “A Course In General Chemistry” (First

edition). New York: Ginn and Company.20 1916 Morgan, W. C. & Lyman, J. A. A laboratory manual in chemistry. New York: The MacMillan Company.21 1916 Newell , L. C. Laboratory manual of inorganic chemistry for colleges. Boston, Mass: D.C. Heath & Co.22 1917 Brownlee, R. B., Fuller, R. W., Hancock, W. J., Sohon, M. D. & Whitsit, J. Laboratory exercises to accompany “First

Principles of Chemistry” (Student: Mary Kagled) New York: Allyn & Bacon.23 1917 Brownlee, R. B., Fuller, R. W., Hancock, W. J., Sohon, M. D. & Whitsit, J. Laboratory exercises to accompany “First

Principles of Chemistry” (Student: Ronald Elden Williamson) New York: Allyn & Bacon.24 1918 Hale, W. J. A laboratory manual of general chemistry. New York: The MacMillan Company.25 1920?? (n.d.) Rudman, R. E. A manual of home science. Auckland, New Zealand: Whitcombe & Tombs Limited.26 1921 Brownlee, R. B., Fuller, R. W., Hancock, W. J., Sohon, M. D. & Whitsit, J. Laboratory exercises to accompany ‘First

principles of chemistry’ (Student: Virginia Nutman) New York: Allyn & Bacon.27 1921 Brownlee, R. B., Fuller, R. W., Hancock, W. J., Sohon, M. D. & Whitsit, J. Laboratory exercises to accompany ‘Elementary

principles of chemistry’ (Student: C. C. Wilson) (Ring bound sheets) New York: Allyn & Bacon.28 1921 Jones, Mary, E. A laboratory study of household chemistry. New York: Allyn and Bacon.29 1921 McPherson, W. & Henderson, W. E. Laboratory manual arranged to accompany the second edition of “A course in

general chemistry” (Student: E. S. George). Boston, Mass: Ginn & Co.30 1922 Holmes, H. N. Laboratory manual of general chemistry (Student: J. C. Watkins). New York: The Macmillan Company.31 1928 Brinkley, S. R., & Kelsey E. B. Laboratory manual: arranged to accompany “Principles of general chemistry’. New

York: The Macmillan Company.32 1928 Walton, J. H. & Krauskopf, F. C. A laboratory manual of general chemistry (Student: Anthony Hellman). Menasha,

Wisconsin: Collegiate Press, George Banta Publishing.33 1929 Kendall, J. A laboratory outline of Smith’s college chemistry (Revised edition) (Student: John F. Higginson). New York:

The Century Co.34 1932 Rosenholtz, J. L. Applied chemistry for nurses with laboratory experiments (Student: Anna L Ficerchia). Philadelphia

and London: W. B. Saunders Company.35 1934 Bennett, H. Practical everyday chemistry. New York: The Chemical Publishing Co. of New York.36 1935 Bigelow, H. E. & Morehouse, F. G. Dominion chemistry manual to accompany Dominion High School chemistry. Toronto:

The Macmillan Company of Canada Limited.37 1932 Richardson, K. B. & Scarlett. A. S. A laboratory manual of general chemistry (larger edition, revised) (Student: Sara

Twiggs). New York: Henry Holt & Co.38 1936 Black, N. H. New laboratory experiments in practical chemistry to accompany Black and Conant’s “New Practical

Chemistry” (Student: Francis Brown). New York: The Macmillan Company.39 1942 Davidheiser, L. Y.(Editor) Lionel Chem-lab manual of experiments. New York: The Lionel Corporation.

APPENDIX 2A Table of alternative conceptions: physical and chemical changes

Manual Student name Observation Explanation physical Explanation chemical Othernumber 5 Anon 1 None - - -

8 Carrie Southard Correct Correct applies defn Correct applies defn -

9 Alta Lemmon Correct Does not apply defn Correct applies defn; Errors -

10 Eric Austin Correct Applied defn incorrectly Applied defn incorrectly

11 Ralph C. Zindel Correct Correct applies defn Correct applies defn but error 4 expts here.1 is dubious

12 A. B. Nilliv Correct Correct applies defn Correct applies defn 4 expts here.1 is dubious

16 Anon 2 Correct Correct applies defn Correct applies defn 2 expts here.

18 Lillian Abra Rhodes Correct Correct applies defn Correct applies defn 3 expts here.

22 Mary Kagled Correct NA Correct applies defn

23 Ronald Elden Williamson Correct NA Correct applies defn

26 Virginia Nutman Mainly correct Omitted Omitted

27 C. C. Wilson Correct NA Correct applies defn

29 E. S. George None - -

32 Anthony Hellman None - -

34 Anna L Ficerchia Expt 3 Correct Does not apply defn Does not apply defn& incorrect obs.

to continue on page 23

18

Aust. J. Ed. Chem., 2006, 66,

Incorporating Graduate Attributes into a Chemistry Major

Trevor C. Brown* and Alan M. Wylie

Chemistry, School of Biological, Biomedical and Molecular Sciences, University of New England, Armidale, NSW,Australia, Trevor.Brown@une.edu.au

AbstractEmployers expect more from university graduates than the subject knowledge and technical skills of a particular discipline.At the University of New England communication, social responsibility, information literacy and problem solving havebeen incorporated into the Bachelor of Science, Chemistry major. Defining these attributes specifically for Chemistrystudents entering an increasingly competitive market place, plus assigning and mapping levels of attainment for theattributes for all units that contribute to the major have achieved this. Any deficiencies in the Chemistry major have beenaddressed and the attributes publicized in both unit and course materials.

IntroductionSince 1998 the Australian Government has requireduniversities to present statements of graduate attributes aspart of their profile submissions. This requirement resultedfrom reports that indicated employers require graduatesthat have well-developed generic skills in addition todiscipline specific content (AC Neilson, 2000; ACDS,2001; Tarrant et al., 2002; RACI, 2005). Employers oftendistinguish the most employable graduates by their genericskills. In 1998 the University of New England introduceda policy called Attributes of a UNE Graduate (UNE, 1998),which articulated the extra skills that students are gainingfrom their courses and recommended seven genericattributes – communication skills, global perspective,information literacy, lifelong learning, problem solving,social responsibility and teamwork.

Subsequent graduate attribute studies (Chapman, 2004)undertaken at UNE indicated that attributes such ascommunication skills and information literacy were notwell developed. Also at a unit level, coordinators took avariety of approaches to the development of the attributesand systematic planning across courses did not occur. Amore meaningful method of incorporating attributes wouldbe across a major, and this has been done for the Chemistrymajor at UNE. Systematic investigation of graduateattributes in all units taught and assessed in a major willhighlight attributes that are either lacking or duplicated.By then documenting and promoting the attributes studentscan develop a portfolio detailing their achievements inthese areas. Hence a Bachelor of Science graduatemajoring in Chemistry at UNE can present to prospectiveemployers a list of the acquired attributes, which meet theneeds of those employers.

In 2004 UNE funded this project to enhance the learningexperience for Chemistry students through explicitteaching, guidance and assessment in relation to graduateattributes, and to assist a more systematic incorporationof the attributes into units. The aims of this project wereto:

• Ensure that the embedding of graduate attributes issystematically planned across the Chemistry major.

• Determine Chemistry specific definitions of attributesthrough discussion amongst unit coordinators.

• Develop descriptors of levels of attainment for eachattribute across all years.

• Identify or develop appropriate teaching andassessment strategies to achieve intended outcomes forattributes.

• Revise teaching and promotional material to includeclearly expressed outcomes, rationale, assessmentcriteria, guidelines etc. for attributes.

Seven UNE Chemistry unit coordinators took part in theproject, while an educational developer (AMW) managed,planned and provided support.

ProcessThe project followed closely the process recommendedby the Australian University Quality Agency (AUQA,2005), with minor modifications to suit the time frame ofthe project. The steps in the process were

a. Prioritise and select key UNE graduate attributes forthe discipline. This required research and discussioninto the attributes required by prospective employers.

b. Define each attribute’s characteristics in terms of thediscipline.

c. Map each characteristic across the Chemistry major.d. Define three levels of attainment for each attribute

based on Bloom’s Taxonomy (Bloom & Krathwohl,1956).

e. Allocate levels of attainment for each attribute acrossthe major.

f. Write descriptors for each unit detailing the learningoutcomes, as well as teaching, learning and assessmentmethodologies.

g. Write publicity material describing the attributes thatwill be obtained during the major.

While unit coordinators are ultimately responsible forincorporating the attributes into their respective unit(s)each step in the process was discussed by all team membersat regular workshops. Each step is critical for the successfulimplementation of the graduate attributes, but the definingand determination of the key attributes in terms of theChemistry discipline and what the employer bodies requirewas a significant influence on the progress and outcomesof the project. This placed a focus on what students wouldneed to graduate with, rather than what was required toacquire the discipline content and skills.

19

Aust. J. Ed. Chem., 2006, 66,

Chemistry-specific transferable skills have been proposedby the Quality Assurance Agency for Higher Education inthe United Kingdom (QAA, 2000). These were also usedas a basis for discussions when deciding on the keyattributes for UNE Chemistry.

The units offered by the discipline of Chemistry at UNEand which contribute to the major consist of two first-year, four second year and six third-year units. A major inthis paper refers to the completion of the followingChemistry units:

CHEM110 General Chemistry ICHEM120 General Chemistry IICHEM201 Physical ChemistryCHEM202 Inorganic ChemistryCHEM203 Environmental and Analytical ChemistryCHEM204 Biological and Organic ChemistryCHEM301 Symmetry and SpectroscopyCHEM302 Organic Structure and ReactivityCHEM303 Biological ChemistryCHEM304 Computational ChemistryCHEM305 Control of Chemical ReactionsCHEM306 Nanomaterials

Key graduate attributes for UNE ChemistryAt the first workshop four of UNE’s seven generic graduateattributes were chosen for incorporation into the Chemistrymajor. Communication, social responsibility, informationliteracy and problem solving were considered to be vitalskills for a Chemistry graduate. Teamwork is also animportant attribute, as indicated by job advertisements anddiscussions with employers, and will be addressed in thefuture, but the chosen four attributes were given the highestpriority and given the time constraints of the project onlythese four were discussed and incorporated in detail.

• Communication – oral, written, graphical andnumerical. Graduates should have skills in presentingscientific material and arguments clearly and correctly,in writing and orally to a range of audiences. Theyshould have the ability to use mathematical techniquesto interpret data from laboratory observations andmeasurements in terms of their significance and theunderlying theory.

• Social responsibility – occupational health and safety,laboratory behaviour, professional ethics,environmental ethics. Graduates should have skills inthe safe handling of chemical materials and the abilityto conduct risk assessments concerning the use ofchemical substances and laboratory procedures. Theyshould be aware of the impact that chemicals andchemical processes can have on the environment andmaintain the highest professional standards in theworkplace.

• Information literacy – library and internet searching,interpreting information, referencing. Graduates shouldhave information retrieval skills in relation to primaryand secondary information sources, includingcomputational skills to access chemical informationand data.

• Problem solving – mathematical, case studies and

chemical. Graduates should be able to apply chemicalknowledge and understanding to the solution ofqualitative and quantitative problems of a familiar andunfamiliar nature. They should also be able torecognize and analyze novel problems and planstrategies for their solution. While techniques to helporganize the problem solving process can be taught,insight, which is the ultimate key to real problemsolving, cannot be taught (Johnstone, 2001).Proficiency in problem solving is usually directlyrelated to expertise in a particular field and sotransferring problem solving skills to other fields,unless very close, can be very poor.

Mapping Levels of AttainmentLevels of attainment for each graduate attribute are listedin Table 1. The three levels were partially based on thecognitive domain from Bloom’s Taxonomy (Bloom &Krathwohl, 1956). In this domain there are six majorcategories (knowledge, comprehension, application,analysis, synthesis and evaluation) starting from thesimplest to the most complex. The three attainment levelscan be approximately associated with the following Level1: knowledge and comprehension; Level 2 - applicationand analysis; Level 3 – synthesis and evaluation. Whilethis represents simplified adoptions of the cognitivedomains due regard was also given to progression throughthe ‘concrete-to-abstract’ dimensions of Bloom’sTaxonomy.

Table 1. Listing of levels of attainment for each of the graduateattributes. Communication levels are further divided into Oral,Written and Graphical and Numerical skills.

Level and description

Communication skills

1. Oral: To describe, discuss and predict the results ofexperiments in the laboratory and to contribute to discussionsin tutorials and workshops.

2. Oral: Students should be competent in giving a short oralpresentation using appropriate structure and technologies totheir peers.

3. Oral: Students should be competent in giving a short oralpresentation using appropriate structure and technologies toa group of experts.

1. Written: Be able to collect and collate information, describethe information and establish simple arguments in writtenform.

2. Written: Be able to utilize well-reasoned arguments,presenting a balanced perspective in their writing supportedby citation and relevant literature.

3. Written: Be able to formulate well-constructed argumentsand to illustrate these in an appropriate manner and in logicalsequence with a variety of writing styles and formats.

1. Graphical and Numerical: Be able to produce clear andaccurate simple graphs, and to use simple algebraictechniques.

2. Graphical and Numerical: Be able to produce clear andaccurate complex graphs, and to use basic calculus, geometryand trigonometry.

3. Graphical and Numerical: Be able to produce clear andaccurate complex graphs using computer software, and touse more advanced mathematical techniques.

20

Aust. J. Ed. Chem., 2006, 66,

Social responsibility skills

1. To recognize the ethical dimensions to many of the issuesassociated with professional practice and that these issues haveto be considered in decision making.

2. To differentiate and evaluate the ethical dimensions to issuesassociated with professional practice.

3. Accept responsibility for outcomes and to apply the learningto workplace situations.

Information literacy skills1. Apply the basic skills required to acquire, organize and present

information.

2. Interpret and assess the information for a range of applications.

3. Initiate research ideas and advanced level of informationliteracy that can be applied to new contexts and situations.

Problem solving skills

1. Show evidence of an understanding of the principles ofproblem solving for a known problem in a narrow disciplinearea.

2. Show evidence of the ability to solve problems for anunknown problem in a narrow discipline area.

3. Apply the process of problem solving in a multidisciplinarycontext, but with a dominant cause of the problem

Communication levels have been allocated for each of thesubdivisions, oral, written and graphical and numericalattributes. For social responsibility, information literacyand problem solving skills only one set of levels werechosen for each generic attribute.

Table 2 shows levels of attainment for all Chemistry unitsoffered for the major. In most cases the teaching, practiceand assessment of these attributes were alreadyincorporated into the major. The mapping, however,highlighted several weaknesses in the course, which havenow been rectified. For many years the only oralcommunication skills practiced or assessed was in theHonours year, and this was at Level 3. Seminars have nowbeen introduced in second-year (CHEM 203) and third-year units (CHEM 306). These will be assessed by thestudent’s peers in CHEM 203 and by the lecturer in CHEM306.

Another weakness was the absence of risk assessmentsundertaken by students in some of the second and thirdyear units. This has now been addressed, as has uniformityin report writing, referencing and graphical analysis.Another important outcome was that, by focusing oninformation literacy, it was obvious that a high qualitysearchable chemical database was essential for Chemistry.This added to the argument and UNE now has access toSciFinder Scholar.

Core first year units in mathematics, biology and physicswere also included in the mapping and were found to alsoprovide excellent introductions to most of the attributes.Mathematics and physics units taught, practiced andassessed numerical, graphical and problem solving skills,while first year biology units provided introductorytraining in oral communication, report writing and librarysearching.

Unit DescriptorsFor each unit, coordinators then wrote specific descriptorsof the graduate attributes in terms of learning outcomes,teaching and learning strategies/activities and assessmenttype. These could then be readily incorporated into UnitOutlines or other unit material that is distributed tostudents. The following details the learning outcomes,while Table 3 provides information on teaching andassessment, which has been included in the Unit Outlinefor the core second-year unit CHEM 201, PhysicalChemistry.

“CHEM 201 provides you with the opportunity to developyour graduate attributes in communication skills, socialresponsibility, problem solving and information literacy.In many cases they build on the skills taught in first-yearchemistry, physics and mathematics.

Graduate attribute learning outcomes

On successfully completing this unit you should be ableto:

• Solve mathematical problems using algebra andelementary calculus.

• Solve moderately challenging problems inthermodynamics, quantum mechanics and chemicalkinetics.

• Identify and describe simple chemical mechanismsfrom kinetic analyses.

• Describe, discuss and predict results of experimentsin the laboratory.

• Follow and take note of descriptions and instructionsduring lectures and lab classes.

• Demonstrate good report writing and report structure.

• Demonstrate a high level of graphical and numericalskills.

• Find information from the library or internet,particularly to supplement the writing of lab reports.

• Locate alternate explanations of difficult concepts fromlibrary and internet resources.

• Provide full referencing details for laboratory reports.

• Demonstrate awareness of chemical hazards.

• Undertake responsible use of chemicals and laboratoryequipment.

• Demonstrate responsible behaviour in the lab.

• Apply ethical and professional conduct in areas oforiginal work and accurate presentation of results.

• Recognize scope of environmental issues associatedwith energy.”

Chemistry Major Publicity MaterialThe following is the material that the working groupdeveloped, and which will be used for publicity purposeson the Chemistry web site and in other course materials.

“UNE has designed its chemistry major to deliver well-rounded chemistry graduates who have all the requiredknowledge and skills to perform at the highest level ofchemistry practice. At UNE we believe that our chemistrygraduates should not only master chemical concepts,

21

Aust. J. Ed. Chem., 2006, 66,

Tab

le 2

. M

appi

ng o

f lev

els

of a

ttain

men

t acr

oss

all u

nits

offe

red

by U

NE

Che

mis

try

for

the

maj

or.

The

sym

bols

T, P

and

A r

efer

to ta

ught

, pra

ctic

ed a

nd a

sses

sed.

The

key

to le

vels

of a

ttain

men

t (1,

2,3)

isgi

ven

in T

able

1.

Firs

t, se

cond

and

third

yea

r un

its a

re id

entif

ied

in th

e na

me

by 1

00, 2

00 o

r 30

0, r

espe

ctiv

ely.

Com

mun

icat

ion

Ora

l1

11

11

11

11

11

12

22

11

11

11

11

11

11

11

11

11

22

1

Wri

tten

11

11

11

22

22

22

22

22

22

33

33

33

33

33

33

33

33

33

Gra

ph &

Num

eric

al1

11

11

12

22

22

22

22

22

23

33

33

32

22

33

33

33

33

3

Soci

al r

espo

nsib

ility

OH

&S

11

11

22

22

22

22

23

33

22

23

33

33

31

11

22

22

22

Lab

beh

avio

ur3

13

13

23

23

23

23

33

33

33

33

3

Prof

essi

onal

eth

ics

31

31

32

32

32

32

33

33

33

33

33

33

Env

iron

men

tal e

thic

s1

11

11

11

12

22

22

22

22

22

22

Info

rmat

ion

Lite

racy

Lib

rary

/Int

erne

t1

11

12

22

11

22

21

11

13

33

22

23

33

Inte

rpre

t inf

o.1

11

11

12

22

22

22

22

22

22

22

22

22

22

22

22

22

22

2

Ref

eren

cing

11

11

11

11

11

11

11

11

11

11

11

11

11

1

Pro

blem

Sol

ving

Mat

hem

atic

al1

11

11

12

22

22

22

22

11

12

22

22

21

11

22

22

22

22

2

Cas

e st

udie

s2

22

22

22

22

11

1

Che

mic

al1

11

11

12

22

22

22

22

22

23

33

33

33

33

33

33

33

33

3

CH

EM

110

CH

EM

120

CH

EM

201

CH

EM

202

CH

EM

203

CH

EM

204

CH

EM

301

CH

EM

302

CH

EM

303

CH

EM

304

*C

HE

M 3

05C

HE

M 3

06

TP

AT

PA

TP

AT

PA

TP

AT

PA

TP

AT

PA

TP

AT

PA

TP

AT

PA

22

Aust. J. Ed. Chem., 2006, 66,

Teaching & Practice Assessment & Feedback

Communication

Oral & Listening Lecturers and demonstrators initiate discussions during lab Qualitative general performanceclasses. Expected listening skills are briefly reviewed at the mark from lab classes. Nofirst lecture. direct assessment

Written Recommended structure of reports and example reports are Three full lab reports arepresented prior to the first laboratory class. Methods for submitted and are fullyerror analyses and citing the literature are also discussed. assessed.

Graphical & Required mathematical knowledge is described in lectures All written forms of assessmentNumerical and in the Unit Outline, but graphical skills are generally test numerical skills, while

assumed knowledge. graphical skills are mostly testedin laboratory reports

Social Responsibility

OH&S General group discussion prior to the first laboratory class Qualitative general performanceand ongoing information to individual students throughout mark from lab classes.all subsequent laboratory classes. Information also providedin lab manual.

Lab behaviour Policies provided in laboratory manual and reviewed prior Qualitative general performanceto first laboratory class. mark from lab classes.

Professional ethics Policies provided in unit outlines and highlighted at first No specific graded assessmentlecture.

Environmental Discussed briefly in some lectures Noneethics

Information literacy

Library/Internet Alternative library texts are listed in Unit Outline and No direct assessment.reviewed at the first lecture.

Interpret. info. Encouraged No direct assessmentReferencing Methods for citing the literature are described prior to the Assessed in three required lab

first lab class. reports.

Problem solving

Mathematical Key mathematical concepts are reviewed in lectures and The four assignments and mostlisted in the Unit Outline. Chemical and physical concepts, of the final exam includerequired for problem solving, are taught in lectures and mathematical problems.detailed in the textbook. Questions requiring mathematicalproblem-solving skills form the basis of assignments,tutorial-exercises and the exam.

Chemical Kinetic concepts build on those taught, practiced and Part of one assignment and partassessed in first year chemistry. New concepts are taught in of the final exam includelectures and detailed in the textbook. Questions requiring chemical-mechanisticchemical-mechanistic problem-solving skills are included in problems.one assignment, tutorial-exercises and the exam.

theory and practice, but they should also emerge with theproficiencies that enable them to work effectively asprofessional chemists. In order to do so they acquire arange of graduate attributes, which the major is designedto provide. The chemistry major focuses on four inparticular that are viewed as critical to successfulprosecution of the discipline of chemistry.

• In Science in general and particularly in chemistry,communication of ideas and results is paramount, sowe teach, practice and assess both written and oralpresentation skills.

Table 3. Unit descriptor for the four generic graduate attributes in the second-year chemistry unit, CHEM 201

• Chemical knowledge and judgement is founded uponinformation - new, old and improved chemicalconcepts, data and ideas. Information literacy or theskills in gathering and critically analysing chemicalinformation is therefore an essential skill for anychemist. For this reason we teach, practice and assessinformation literacy skills.

• Social responsibility is vital in the professionalexecution of chemistry. Issues such as occupationalhealth and safety, professional ethics, responsiblelaboratory behaviour and environmental ethicsregularly arise in the chemistry work place. For this

23

Aust. J. Ed. Chem., 2006, 66,

Acknowledgements

The authors thank Dr Chris Fellows, Assoc. Prof. KiyoFujimori, Assoc. Prof. Stephen Glover, Prof. Max Gunter,Dr Rowan Hollingworth and Dr Peter Lye, who were theChemistry unit coordinators and Mrs Lynne Chapman forher initiative and encouragement. Thank you to ProfessorDerek Nonhebel from the University of Strathclyde forhis expert guidance and advice and for reviewing theoutcomes of this project. A 2004 UNE TeachingDevelopment Grant funded the project.

ReferencesACDS (2001), Why do a Science Degree? Australian Council of Deansof Science, Occasional Paper No.2, http://www.acds.edu.au.ACNielsen (2000), Employer Satisfaction with Graduate Skills, ResearchReport, EIP, ACNielsen Research Services, http://www.dest.gov.au/archive/highered/eippubs/eip99-7/execsum99_7.htmAQUA (2005), Graduate Attribute Mapping in Undergraduate Programs,Good Practice: Database, http://www.auqa.edu.au/gp/search/detail.php?gp_id=1102.Bloom, B.S. & Krathwohl D.R. (1956), Taxonomy of EducationalObjectives, The Classification of Educational Goals. Handbook I:Cognitive Domains, New York, Longmans, Green.Chapman, L. (2004), Graduate Attributes Resource Guide: IntegratingGraduate Attributes into Undergraduate Curricula, University of NewEngland, Armidale, NSW.Johnstone, A.H. (2001). Can problem solving be taught? UniversityChemical Education, 5, 69-73.QAA (2000), General Guidelines for the Academic Review of BachelorsHonours Degree Programmes in Chemistry, Quality Assurance Agencyfor Higher Education, Gloucester, UK, http://www.qaa.ac.uk/crntwork/benchmark/chemistry.html.RACI (2005), Future of Chemistry Study: Supply and Demand ofChemists, The Royal Australian Chemical Institute, Interim Report, http://www.raci.org.au/future/futureofchemistry.html.Tarrant, M., Balzary, S., Byme, P., Curtin, B., Judd, M., Robinson, C.and Calver, R. (2002), Employability Skills for the Future, AustralianChamber of Commerce and Industry and the Business Council ofAustralia, Department of Education and Training, www.dest.gov.au/ty/publications/employability-skills/final-report.pdfUNE (1998), Attributes of a UNE Graduate, Office of the Secretariat,University of New England, http://www.une.edu.au/offsect/une_grad_attributes.htm

reason the chemistry major is designed to developrecognition of these issues and skills in socialresponsibility.

• Chemistry is about problem solving – problems ofboth a qualitative and quantitative nature. Much of whata chemist does involves the challenge of solving somekind of problem. Throughout the chemistry major weprovide a thorough grounding in many aspects ofproblem solving, including ways of recognising andaddressing a wide range of chemical problems.

In undertaking a UNE chemistry major you will graduateas a recognised and trained practitioner of the discipline;we will provide you with the knowledge, skills andattitudes that are particularly sought by employers. TheUNE chemistry major is fully accredited by the RoyalAustralian Chemical Institute.”

ConclusionA major outcome of this project is that by focusing on keygraduate attributes the student learning experience in theChemistry major is enhanced. The essential subjectmaterial will continue to be covered, but communication,social responsibility, information literacy and problemsolving are now systematically and effectively developedthroughout the course and are advertised as such to ourstudents.

The project highlighted some weaknesses, but mostattributes were already incorporated into the major.Attributes were previously not promoted or documentedand so students were unable to demonstrate to employerstheir achievements in these areas. The success or otherwiseof students attaining and developing the required attributeswill be difficult to quantify, but will be evaluated duringthe three-yearly review of the Bachelor of Science.

APPENDIX 2B Table of alternative conceptions: mixtures and compounds.

Manual Student name Observation Explanation mixture Explanation compound Othernumber 5 Anon 1 Correct Correct Applies defn Correct applies defn -

8 Carrie Southard Correct Correct applies defn Alternative conception apparent -

9 Alta Lemmon Correct Not asked to explain. error chemical change -

11 Ralph C. Zindel Correct Question really on chemical change

12 A. B. Nilliv Correct Question really on chemical change

16 Anon 2 p.15 Correct No conclusion No conclusion

18 Lillian Abra Rhodes Correct Correct Applies defn Correct applies defn

32 Anthony Hellman Correct Correct Applies defn Correct applies defn

34 Anna L Ficerchia Mainly Correct Correct Applies defn Very muddled Alternativeconception apparent

Continuation from page 17:

Children’s alternative conceptions of physical and chemical change obtained fromhistorical sources compared with those found in other recent studies

24

Aust. J. Ed. Chem., 2006, 66,

Alternative Demonstrations of Slow Processes. III:A Demonstration and Video Clip Showing Effusion in Liquids

Vladimir M. Petrusevski, Marina Monkovic and Metodija Najdoski

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Sts. Cyril and Methodius University, Arhimedova 5,PO Box 162, 1000 Skopje, Republic of Macedonia. E-mail: vladop@iunona.pmf.ukim.edu.mk

AbstractEffusion in liquids is much slower compared to that occurring in gases. It can be easily demonstrated using standardequipment based on a porous cup (full of colored glycerol), and immersed in a beaker with water. Water slowly entersthe cup (despite its lower density, compared to that of glycerol). The effusion process can be monitored qualitativelythrough the change of the level of glycerol in the glass tube connected to the porous cup. A 44 s video clip containing270 photographs (taken in a 90 minute period) has also been prepared, as a time saving demonstration of effusion inliquids and one more demonstration concerning relatively slow processes.

Key words: transport phenomena, effusion; liquids; glycerol; water; video clip

Introduction

Effusion is often defined as a process of leaking of a fluidthrough a narrow pinhole [1–3] or, alternatively, as a(hindered) diffusion through a porous wall [4]. The laterprocess is sometimes referred to as a transfusion, althoughthere is no principal difference between the two, since theprocess of transfusion can always be considered as multipleeffusion (each pore of the porous wall being equivalent toa single narrow pinhole).

It is well known from physical chemistry textbooks [1]that the rate of effusion in a given gas is:

where N is the number of molecules, t is the time, p is thepressure of the gas, A

o is the area of the hole through which

the effusion process takes place, NA is the Avogadro’s

constant, R is the universal gas constant, T is thethermodynamic temperature, and M is the molar mass ofthe gas. The above equation is derived from the kinetictheory of gases.

Knowing that for an ideal gas pV = nRT, it is easy to provethe following relation for the rate of effusion:

Thus it is obvious that the rate of effusion is higher thehigher the temperature and the lower the mass of the gasmolecules. If the rates of effusion of two different gasesare compared, providing the temperature is the same, oneeasily comes to:

where r denotes the rate of effusion, and indices 1 and 2refer to the first and second gas, respectively. Eq. 3 actuallygives the well-known Graham’s law of effusion.

˘ ´

Demonstrations of effusion in gaseous state are numerous[4–7], albeit sometimes erroneously identified as diffusion[6,7]. The most striking of all of these is the hydrogenfountain [4–5], due to the fact that hydrogen is the lightestof all gases, so the rate of effusion (cf. Eq. 2) is the highestpossible one (providing one demonstrates effusion ofdifferent gases against air as a standard). To the best ofour knowledge, no demonstration of effusion in liquidshas been offered so far. Having this in mind, we decidedto develop such an experiment that will result in ademonstration, which is:

• effective• fast enough• cheap• safe• free of waste that contains environmental pollutants

Our attempts appeared to be successful and in agreementwith all above requirements, as will be elaborated shortly.

Figure 1:Effusion in liquids – a schematic view: lighter molecules (water)move faster through the porous wall than the heavier ones(glycerol).

(1)

(2)

(3)

25

Aust. J. Ed. Chem., 2006, 66,

ExperimentalEquipment and chemicals. The demonstration could beperformed using simple and inexpensive equipment andchemicals, like:• a porous cup (≈ 100 mL; one made of burned clay

works fine)• a beaker (≈ 400 mL)

• a glass bottle (≈ 200 mL)

• graduated glass tube (≈ 30 cm in length)• 1-hole rubber stopper, to fit both the porous cup and

the glass tube• glycerol (cca 100 mL)• deionized or distilled water• methylene blue (cca 100 mg)All equipment is presented in Fig. 2.

1 hour the level is much higher then it was in the beginning(cf. Figs. 3␣ a–d).

Figure 2. Equipment used for demonstration of effusion in liquids:porous cup (a); beaker (b); bottle filled with colored glycerol (c);graduated glass tube (d); one hole rubber stopper (e).

Preparation for the demonstration. The methylene blue(50–100␣ mg) is first dissolved in cca 100 mL of glycerol,in a glass bottle. In order to obtain homogenous solutionit may be necessary to shake the bottle several times duringabout half an hour.

It is necessary to fill the porous cup with water, few hoursbefore the demonstration (or, better, overnight). If a drycup is used, some time will be wasted waiting for theliquids to fill the pores, during which process the systemmay show odd behavior (like the level of colored glycerolin the glass tube decreasing with time in the beginning ofthe demonstration, instead of increasing). An independentcheck proved that basically the same results are obtainedif the porous cup is first soaked in glycerol.

The demonstration. The porous cup (previously filledwith water, or kept under water) is filled to the top withthe colored glycerol. After that the cup is stoppered withthe rubber stopper (the graduated glass passes through thehole). The cup is stoppered tightly enough, to sustain avisible level of the colored glycerol in the tube. The beakeris filled with water by two thirds of its volume, and isplaced on a suitable base in front of white screen.

The demonstration starts when the assembled equipmentis placed in the beaker with water. In few minutes itbecomes obvious that the level of the colored liquid in thetube increases. This means that, despite of its lower density,water enters the cup through the porous wall. After about

Figure 3: Effusion in liquids: experimental setup (a); glycerol isadded to the porous cup (b); water is added to the beaker – startof demonstration (c); and end of demonstration (d). The initiallevel of glycerol is marked on the white styrofoam block next tothe beaker (cf. Figs. 3 c–d) and serves as a point of reference.The porous cup has seemingly expanded in the latter two figures,as a consequence of the change of the optical properties of themedium (the refraction index of water is ≈ 1.33, and that of air isvery close to 1).

At first sight the demonstration is similar to osmosis.However, there is a very important difference: osmosis isthe movement of solvent particles from high solventconcentration to low solvent concentration through a semi-permeable membrane, which only allows the solventmolecules to move through. For example, if we usedglycerol/water solution in contact with pure water, usingsemi-permeable membrane, the water molecules wouldmove into the glycerol/water solution. However, when weuse porous membrane, both water and glycerol moleculesare now able to transfer and in this case the movement ofthe water molecules into the glycerol/water solution (orthe pure glycerol, as in this case) is due to effusion. Thewater molecules are lighter than glycerol molecules andthus the rate of effusion of water molecules is faster thanfor glycerol molecules, assuming liquids obey Graham’slaw.

The porous walls of the used cup are transparent in bothdirections. After a longer period of time (about 5–6 hours),one could see that the water in the beaker has light bluecolor. This is due to the glycerol molecules (and themethylene blue dye) that traveled by effusion in thereversed direction. The process is from the very beginning(unlike osmosis) a 2-way process, albeit the rate of thereversed process is slower as it should be. Even morearguments that the demonstrated process is indeed ademonstration of effusion are given in the subheadingNotes.

The process is much slower than is effusion in gases [4–7]. However, it is still possible to demonstrate it in a lessonperiod. For those that prefer to organize their lecture usingclassical demonstrations (i.e. experiments that last onlyfew minutes), we offer a video clip of the process,

26

Aust. J. Ed. Chem., 2006, 66,

employing the so-called fast-motion technique [8,9].Snapshots were taken in 90 minutes period, during whichthe level of colored glycerol increases by more than 10cm. The photos were linked to make a short movie (cf.Movie 1).

The demonstration is appropriate for both 1st year studentswithin the general chemistry course, and for 2nd or 3rd yearstudents within advanced physical chemistry courses. Noparticular background knowledge is required for the former(it is enough to understand the basics of diffusion, effusionand osmosis). The latter are expected to be familiar withthe kinetic theory of gases, the properties and differencesin behavior of both gasses and liquids. The purpose of thedemonstration is to complement existing demonstrationson gas effusion, and to make a clear-cut distinction betweeneffusion in liquids and osmosis. After this demo isperformed, the importance of the existence ofsemipermeable membrane becomes obvious.

Safety tips and disposalThe glycerol, as any other alcohol, is somewhat toxic. Ifswallowed, by accident, call for physician immediately.If spilled just wash it with water. The waste may freely bedisposed in the sink and flushed with water. Whenperforming the demo, safety goggles should be worn (asalways, when performing chemical demonstrations). Somecare is also needed when inserting the glass tube into therubber stopper (the tube may crack and hurt the instructor).

NotesWe checked that the demonstration might also beperformed with different pairs of liquids, like ethanol–amyl alcohol or ethanol–carbon tetrachloride pairs.However, it is both slower (due to lower molar mass ratios,in the case of ethanol–amyl alcohol pair [10], and probablydue to much higher density of CCl

4 in the case of C

2H

5OH–

CCl4 pair [11]), and it is environmentally unacceptable

(particularly with CCl4 or other halogen derivatives of

hydrocarbons).

One could have doubts whether the process described isdue to effusion, and not due to osmotic pressure gradientperhaps? However, the osmotic pressure is a colligativeproperty. Therefore, if one fills the cup with solution ofwater in glycerol, against pure glycerol in the beaker, theglycerol should enter the cup. Actually, in reality theopposite happens! It is always the liquid with lowermolecular mass that moves faster through the porous walls,so it is not due to osmosis.

In case of doubt whether perhaps viscosity differencesmight be at the origin of the phenomenon (thus expectingthat the liquid with higher viscosity should run slower),one may argue that in the ethanol–CCl

4 pair it is ethanol

that moves faster through the porous wall, despite itssomewhat higher viscosity. Obviously, the role of themolecular mass is in all studied cases the dominant factor.

In line with what was said above, any pair of completelymiscible solvents could in principle be used. However,for best results it is important that the ratio of molar massesof the two liquids should be as high as possible (cf. Eq. 3)

[12]. From our experience, the pair water–glycerol is closeto the ideal pair for this demonstration.

One may object that the ratio of the molar masses formonomers of water and glycerol does not give a correctestimate of the actual mass ratios, for oligomers are presentin both water and glycerol. One would expect that thisratio might be used at least semiquantitatively, as a firstguess value for the principal factor that governs the rateof effusion. Actually, some time ago a publication appearedthat supports very strongly the notion of effusion in liquids,despite the very strong intermolecular interactions andmolecular velocity distributions that deviate significantlyfrom Maxwellian [13].

ConclusionThe offered demonstration may be performed easily. Ituses some simple and cheap chemicals, and very commonequipment. The effusion process becomes obvious afterfew minutes. Providing a large porous vessel is used (witha volume of at least 1 and preferably 2 L), it is possible towitness the transfer of liquid (water) in real time (up toone minute, a time period that might be compared withthe duration of the offered video clip). This is both educa-tional and a novel demonstration, since no similarexperiment was found in the literature after a thoroughsearch.

The offered video clip (employing the fast motiontechnique) may be used as time saving alternative. Thestudents liked the demonstration (they seem to like alldemos based on video clips that ‘accelerate’ the otherwiseslow processes [8,9]).

In our next contribution attention will be paid to fewdemonstrations of diffusion processes (some new and somewell known), in both gases and liquids, as well as topreparation of suitable video clips.

Supporting materialFigures 2 & 3 are photographs taken with FUJIFILMFinePIX4700 digital camera. The movie (LiqEffus.mpg)is a collection of photographs that were taken byToUcamXS (Phillips) digital camera, which was coupledto and software controlled by a PC. The movieLiqEffus.mpg was a result of linking 270 snapshots (eachof 640×480 resolution) and is playable with the WindowsMedia Player. When playing the file, it is recommendedto view it with the ‘full screen‘ option. The added musicis, of course, optional (one can always switch off thespeakers).

Movie. A 44 seconds movie (LiqEffus.mpg) showing thechange of the level of colored glycerol in the glass tube,due to effusion of water.

References1. Atkins, P., de Paula, J. Physical Chemistry, Seventh Edition; Oxford

University Press: Oxford, 1994; pp 824–825.2. Moore, W. J. Physical Chemistry, Fifth Edition; Longman Group

Ltd.: London, 1974; pp 124–126.3. Daniels, F; Alberty, R. A. Physical Chemistry, Fourth Edition

(Russian translation); Mir: Moscow, 1978; pp 270–271.

to continue on page 30

27

Aust. J. Ed. Chem., 2006, 66,

Chemistry Vocabulary: Part 2, Structure Related Terms.1

Nittala S. Sarma

School of Chemistry, Andhra University, Visakhapatnam-530 003, India; Email: nittalas@lycos.com

1 Dedicated to Nittala Kameswari, my late mother for initiating and nourishing my involvement in vocabulary.

Many technical terms of chemistry derive from commonGreek and Latin root words that are much fewer in number.Knowledge of these root words can help in understandingwhat exactly the terms stand for. In continuation of theearlier discussion on chemistry terms at macro/processlevel,1 I concentrate in this article, on the terms associatedwith chemistry at the micro/structure level. It would beappropriate to begin with the basic building blocks of allchemicals (matter). The now common word atom (Greek:a=without, tomos=to slice) coined by Dalton, meansunsliceable. The knowledge of the etymology of atom ishelpful to comprehend terms like tomography, microtome,hysterectomy etc.2 The term molecule is from moles thatmeans mass in Latin.

Coordination Compounds:A ligand (Greek: ligare=to bind; see part 1) is an atom/molecule/radical/ion, which forms a complex with a centralatom. The suffix and (that signifies the specific purposeand nothing else) of ligand is present in coronand, cavitand,cryptand, podand, spherand etc. They rhyme with errand(O.N. arr=messenger). A coronand (Latin: coranus=crown) is a monocyclic ligand assembly that contains threeor more binding sites, e.g., the O atoms of crown ether;the resulting adduct is called as coronate. Cavitands arecompounds having a cavity large enough to host/accommodate other molecules. The products are inclusioncompounds. A cryptand (Greek: kryptos=hidden) like acoronand, is also a molecule with three or more bindingsites held together by covalent bonds, and having a cavity;but in which another molecular entity can hide by bondingwith the binding sites. The terms podand and spherandare used for certain specific ligand assemblies.3

In mathematics, similar rhyming terms are operand,multiplicand, radicand, summand etc. An operand is aquantity upon which a mathematical operation isperformed. A multiplicand is a number to be multipliedby another. A radicand is the quantity under a radical sign.A summand is a part of a sum. In psychology, analysand,is a person undergoing psychoanalysis.

Hapticity (Greek: haptein= to fasten) is the number ofligand atoms simultaneously bound to a metal cluster.Chela is the latinised form of chele in Greek. It is theprehensile claw of an arthropod (animal). Chelate is acoordination compound in which a central metallic ion isattached to an organic molecule at two or more positions(see later for cheletropic). In Latin, clathrare is to furnishwith a lattice. Clathrate is a molecular compound havingone component enclosed in the cavities of anothercomponent. Clathrochelates have both the features of

chelate and clathrate, e.g., the cage complex formed fromdimethylglyoxime, BF3 and Co (III). They are also calledcryptates, since the metal (Co) is hidden at the center ofthe cage. Agostos in Greek is to clasp/to draw towards/tohold oneself. Agostic designates structures in which a Hatom is bonded to a C (or Si) atom as well as (anunsaturated) metal centre.

Catena, in Latin, means chain. Catenation (of carbon) isinvolved in most organic and some inorganic compounds.In naming the inorganic and co-ordination polymers, asper the IUPAC nomenclature, the constitutional repeatingunit (CRU) is first selected and suitably prefixed. Forexample, the polymer [Sn(CH3)2]n is named as catena-poly[dimethyl tin].4

Similar and Different:(i) Similar (iso/homo): Isotopes (topos=place) occupythe same place (position) in the periodic table; that of theelement. Isobars (baros=heavy) have the same numberof the mass contributing neutrons and protons together.Isotones are nuclei of different elements but with the samenumber of neutrons. Isodiapheres (Greek: pherein=tocarry) are nuclides having the same difference betweentotals of neutrons and protons. Isologues are compoundswith similar molecular structure but containing differentatoms of the same valency. Isotopomer (Greek: meros=part) is the contraction of isotopic isomer. Isotopomershave the same number of each isotopic atom but differingin their positions. Isotopomers can be either constitutionalisomers or isotopic stereoisomers. The suffix mer occursin various other terms, e.g., elastomer (Greek: elastikos=todrive), rotamer, etc. This affix, in co-ordinationnomenclature, means meridional (mer-isomer), as opposedto facial (fac-isomer), two geometrical descriptors, apartfrom cis and trans. Isotopologue is a molecular entitythat differs only in isotopic composition, e.g., H

2O, HOD,

D2O. Isozyme, or isoenzyme is one of a group of related

enzymes catalysing the same reaction but having differentchemical, physical, and biochemical properties.

Isohydric solutions have the same pH value (H+ ionconcentration). Isoelectric point is the pH at which theviscosity and conductivity are at their minimum. Anisodisperse substance is dispersible in solutions havingthe same pH. Isovalent resonance is the form of resonancein which all resonating structures contain the same numberof bonds. Isosteric (Greek: stereos=solid) molecules havesimilar size and shape.

In crystallography, isometric system is the cubic system.Isodimorphous substances exist in two isomorphous

28

Aust. J. Ed. Chem., 2006, 66,

crystalline forms. Isodesmic structure (Greek: desmos=achain; desme=bundle) is crystal structure with equal latticebonding in all directions, and no distinct internal groups.

Isocycles have the same element in the ring structure.Isopolyanions are polymeric anions in which no extraelements are present. Isopoly anions are very stablecomplexes, e.g., heptamolydate (Mo

7O

24)6- (also called as

the paramolybdate).

A prefix of similar meaning is homo (Greek:homos=similar), e.g., homocycles, homovalent resonance,homopolar bond, etc. The homopolar bond is morecommonly known as covalent bond. A homoazeotrope(Greek: zeiin=to boil; see zeolites below) has only oneliquid phase distilling without change of composition.Homopolymers contain a single monomer as the repeatingunit, e.g., polythene (ethylene is the monomer) and naturalrubber (isoprene is the monomer). Homochiral is whenthe optical isomers are enantiomerically (in old literature,enantiomers were referred as antipodes) pure(enantiopure). Complexes with only one type of ligandare called homoleptic (Greek: leptos=slender).Superposable ligands are called homomorphic.Homotopic groups (or atoms) of a molecule are thoserelated by an n-fold (n=2,3, etc.) rotation axis, e.g., Clatom in CHCl

3 (3-fold) and COOH group in chiral tartaric

acid (2-fold).

(ii) Different (hetero): The opposite of iso/homo is hetero(Greek: heteros=other), e.g., heterocycles, heterovalentresonance, etc. Heterovalent resonance is when thevarious resonating structures contain different number ofbonds. Heteropolar bond is an ionic bond and is knownby other names also, e.g., electrovalent bond, polar bond,and electrostatic bond. A heteroazeotrope has two ormore liquid phases distilling without change of meancomposition. The opposite of this is heterozeotrope withliquid constituents of limited miscibility. Heteropolymerscontain monomers of different structures and heterolepticcomplexes have different ligands.

Homocatenation is when only one element/structuralmoiety is involved, and heterocatenation is when differentelements (as in pyrophosphate) are involved. Heteropolyanions, with appropriate elements embedded in the cagestructure e.g., (PMo

12O

40)3- are more stable than

isopolyanions.

Shapes of molecules:(i) General Shape: Morphe is shape in Greek, giving riseto terms, e.g., amorphous, isomorphic, idiomorphic(Greek: idios=own, distinct) and polymorphic shapestaken by solid substances. Allotriomorphic (Greek:allotrio=alien) means non-crystalline in outward form (butcrystalline in internal structure). In a mesomorphic(Greek: mesos=middle) substance, atoms/molecules areoriented in parallel planes of a layered structure. Suchsubstances, e.g., a detergent, are associated with smecticphase (Latin: smectus=cleansing; Greek=soapy).

The orderly close packed hexagonal arrangement ofmicelles in concentrated surfactant solutions as arrays of

long cylinders is called a lyotropic mesomorph(mesos=middle). A morphotropic transition is an abruptchange in the structure of a solid solution that occurs whenthe composition is gradually varied. A monotropictransition refers to a single morphotype that occurs in theirreversible transition from a metastable polymorphic formto the stable polymorph, e.g., transition of aragonite tocalcite (CaCO

3). In polymorhic transition, a reversible

transition occurs at a certain temperature and pressure(the inversion point) of a solid crystalline phase to anotherphase of the same chemical composition but with adifferent crystal structure. Polymorphic transition issynonymous with enantiotropic transition.

(ii) Angles and Faces: The torsion angle (also calleddihedral angle) between bonds of two groups (A and D inthe A-B-C-D system) can be variable. Its designation isdone depending on the range to which the torsion anglebelongs– synperiplanar (sp, 0o to 30o), synclinal (sc, 30o

to 90o and –30o to 90o), anticlinal (ac, 90o to 150o and –90o

to –150o) and antiperiplanar (ap, ±150o to 180o).

Gonia is angle, and hedra is seat (face/base) in Latin.Agonist and antagonist are angle – related terms.4 Trigonal(bipyramidal), hexagonal and octagonal shapes of crystalgeometry are common. A delta (_) hedron is a polygonwith all faces that are equilateral (later=side) triangles.The common morphologies of crystals are tetrahedral(n=4) and octahedral (6), and trigonal bipyramid (5). Afew eicosahedral (20 faces, n=12) molecules are known.They include some of the boranes andbuckminsterfullerene. The latter name is fromBuckminster Fuller, an American architect known for hisdesigns of hemispherical domes consisting of pentagonaland hexagonal faces. Enneahedron (ennea=nine) is a solidfigure with nine faces.

The organo metallic cage compounds are of differentgeometries depending on the number of frameworkelectrons involved – closo (2n+2), nido (2n+4), arachno(2n+6) or hypho (2n+8). In Greek, closo means closed,arachno means spider’s web and hypho means net. InLatin, nido means nest, giving an indication of themorphology of the structures.

Three Degrees of correctness:(i) Most correct (ortho): In Greek, orthos means straight,upright and correct. It denotes the most common form,compared to para which means beside and meta whichmeans after or beyond. A justification of these prefixes inorganic (aromatic) nomenclature is given earlier.2

Orthohydrogen molecule has the more stable parallel spincombination (triplet state) of the two H atoms; it is theright (or more abundant) form.

In the reaction of oxides and anhydrides with waterforming oxyacids, the extent of hydration can be variable.When the hydration is complete, the corresponding acidis called orthoacid., e.g., orthophosphoric acid H

3PO

4, by

hydration of P2O

5. Ortho is often implied; cf., arsenite

(H2AsO

3-), bisulphite (HSO

3-), borate (H

2BO

3-), silicate

(H3SiO

4-), and vanadate (H

2VO

4-), which are all orthoacid

conjugates.

29

Aust. J. Ed. Chem., 2006, 66,

(ii) Also correct (para): Parahydrogen molecule has theless stable antiparllel spin combination (singlet state) ofthe two H atoms; it constitutes only ~25% STP conditions,but an increasing fraction at low temperatures.

(iii) Least correct (meta): The acids formed byincomplete hydration are called meta acids, e.g.,metaphosphoric acid (HPO

3), as opposed to

orthophosphoric acid (H3PO

4). The meta acids

corresponding to the above ortho acid conjugates aremetaarsenite (AsO

2-), metabisulphite (also called

pyrosulphite, S2O

52-), metaborate (BO

2-), metasilicate

(HSiO3-), and metavanadate (VO

3-). The periodate (IO

4-)

is referred only as metaperiodate.

The oxide of tungsten WO3, is the parent of (ortho) tungstic

acid H2WO

4, and isopoly acids (see above for iso), the

conjugates of which are metatungstate (H2W

12O

406-),

paratungstate A (W7O

246-), and paratungstate B

(H2W

12O

4210-). Their designation follows the fact that for

a uniform association of 3 molecules of H2O, 3, 9, 7, and

6 molecules of WO3 are required for the four tungstates

respectively.

False (pseudo):Pseudo means false in Greek. Organic nitrates, e.g., benzylnitrate are pseudo acids, which react with HNO

2 to give

nitrolic acid, if primary, and pseudonitrolic acid, ifsecondary. This prefix pseudo also occurs in a variety ofother contexts, e.g., pseudoaxial, pseudoequatorial, pseudo(zero, first, second, etc.) order reactions, pseudopericyclic(transformation), pseudocopolymer, pseudooligomer,pseudoreversible (indicator), and pseudoureas (isoureas;now obsolescent).

In cyclopentane ring, puckering occurs due to the strainwhich, however, rotates among the 5 carbons in such away that at any given time, no particular C is out-of-plane.This effect is called pseudorotation. A special case ofpseudorotation is Berry pseudo rotation. In the trigonalbipyramid (TBP) molecule like that of PF

5, two F atoms

should behave differently from the 3 others. However,they behave identically (in the 19F NMR) due to a fastscrambling resulting in a new TBP structure (via a squareplanar transition state). Because the two TBP structuresare related to each other by simple rotation, the process iscalled pseudorotation. As this was first suggested by Berry,it is also called as Berry pseudorotation.

Negation:A (or an) is a prefix used for opposite meanings, e.g.,amorphous (morphe=shape), anharmonic (Greek: harmos=a joint fitting), asymptotic (Greek: a+sym=together+ptotos=apt to fall), aneroid (Greek: neros=wet+eidos=form), etc. Agranular carbon is a monogranular ormonolithic carbon material with homogeneousmicrostructure. Aglycon (or, aglycone) is the non-sugarcompound remaining after replacement of the glycosylgroup from a glycoside by a H atom. Agonist, in Englishmeans attack/threat. In (bio)chemistry, it stands for asubstance that can bind to cell receptors and produce itsown response. The opposite of agonist is antagonist.

Antagonist is a substance that reverses or reduces the effectinduced by an agonist.

Good to be:Eu is a Greek prefix, meaning good. Its combination withtaxis (=behaviour/arrangement) gives eutectic. Eutecticrelates to a mixture of two or more substances having aminimum melting point. Such a mixture behaves in somerespects like a pure compound. Because of the sharpmelting point, the eutectic mixture was originally thoughtto be a single compound. An eucolloid (Greek: kolla=glue,eidos=form) has a large particle diameter, more than 250nm. An eutectic mixture, in aqueous solution, is calledcryohydrate, and the eutectic point as the cryohydric point(see the previous article for cryo1). In an euatmoticreaction, a single vapour phase produced during anisothermal, reversible reaction between two (or more) solidphases. An euhedral (hedra=base) crystal has well definedfaces (it is also called as idiomorphic crystal; idios=own,distinct in Greek), formed due to the free room availableduring crystallisation. Its opposite is allotriomorphic (seebefore) crystal.

Common Biological Terms for Chemists:Cytoplasm (Greek: plassein=to mould, plastos=moulded,c.f., plasma, chloroplast) is the protoplasm of a cell, apartfrom that of the nucleus. Erythrocytes (Greek: erythros=red) are red blood corpuscles, leucocytes (Greek: leukos=white) are white corpuscles of the blood or lymph. Genoccurs as suffix (Greek: gennaine=to generate) inandrogen, and estrogen. Moneres in Greek is single. Ahormone (Greek: horme=impulse) is an internal secretionwhich on reaching some part of a plant/animal bodyexercises a physiological action, while pheromone (Greek:pherein=to bear) is a chemical substance secreted by ananimal which influences the behaviour of others of itsspecies, e.g., queen bee substance. It can be termed as anectohormone. In chemical ecology (Greek: oikos=house,logos=discourse), allomone (Greek: allos=other) has asimilar genealogy.

Soma in Greek is body, e.g., chromsome (Greek: chroma=colour). Trophe (Greek: trophos=food) is nourishment,e.g., autotroph, auxotroph, heterotroph, mesotroph(mesos=middle), polytroph, oligotrophic (oligos=few) andeutrophic (eu=well). Voro in Latin is to devour, e.g.,herbivore, insectivore, omnivore (Latin: omnis=all). Anenzyme (Greek: zyme=leaven; zymos=fermentation) is asubstance that helps fermentation. A zymogen is aproenzyme. Isozymes are electrophoretically distinctforms of an enzyme with identical function.

Some Left-outs:Zeolites are any of a large group of aluminosilicates ofNa, K, Ca, and Ba, containing very loosely held water.The word is derived from the Greek root zeiin which meansto boil and lithos, a stone, and is an allusion to the factthat many zeolites intumesce (i.e., swell up) under the blowpipe. A zwitter ion (German: zwitter=a hybrid) is an ioncarrying both a positive and a negative charge, e.g., aminoacid. Viscose (Latin: viscosus=sticky) is the viscoussodium salt of cellulose xanthate.

30

Aust. J. Ed. Chem., 2006, 66,

Conclusion:Historically, most chemistry terms are derived fromClassical Greek and Latin word roots. The trend stillcontinues as newer concepts are being developed and givennames. There are about a dozen most frequently usedaffixes – ortho, tropo, mer, meta, iso, para, hetero, syn,homo, topo, dia and pseudo. For a starter, the knowledgeof the etymology of chemistry terms can potentiallyremove their often intimidating appearance and helpunderstand the concepts represented by them succinctly.And this can be a basis for further development. As oneprogresses, it may appear in few cases that due to theadvancement in science the original concepts got refinedthough, they still retain the original terms coined for them,and that the etymology approach may be misleading. Nottaking the etymology approach so far that it is an addedburden; on the other hand, a means to take positively onthe heavily loaded chemistry curriculum is expected to beone step in replacing sobriety with a pleasurable learningexperience.

Literature Cited1. Sarma, N. S., Aust. J. Edu. Chem, 2005, 65, 32.2. Sarma, N. S., J. Chem. Edu., Madison (USA), 2004, 81, 1437.3. McNaught, A.D., and Wilkinson, A., Compendium of Chemical

Terminology, The Gold Book, 2nd ed, IUPAC & Blackwell Science,1997.

4. Leigh, G.J., Favre, H.A., and Metanomski, W.V., Principles ofChemical Nomenclature, A Guide to IUPAC Recommendations,Blackwell Science, 1998.

Continuation from page 26:Alternative Demonstrations of Slow Processes. III:A Demonstration and Video Clip Showing Effusion in Liquids

4. Summerlin, L. R.; Borgford, C. L; Ealy, B. J. ChemicalDemonstrations: A sourcebook for Teachers; American ChemicalSociety: Washington DC, 1987; Vol. 2, pp 28–29.

5. Shakhashiri, B. Z. Chemical Demonstrations: A Handbook forTeachers of Chemistry; The Wisconsin University Press:Madison, WI, 1985, Vol. 2, pp 55–58.

6. Fowles, G. F. Lecture Experiments in Chemistry; Bell & SonsLtd: London, 1959; pp 18–19.

7. Verhovskii, V. N. Techniques and Methods of PerformingChemistry Experiments in a College; Zavod za izdavanjeudzbenika SR Srbije: Beograd, 1965: Vol. 2, pp 149–154(translation from Russian into Serbian).

8. Najdoski, M.; Aleksovska, R.; Petrusevski, V. M. The Chem.Educator, 2001, 6, 319–320.

9. Petrusevski, V. M; Monkovic, M; Najdoski, M. The Chem.Educator, 2004, 9, 39–41.

10. Of course, if the molar masses are exactly the same, one wouldexpect, to a first approximation, equal rates of effusion for bothliquids and hence no changes of the liquid column in the glasstube.

11. The importance of the relative densities of the liquid pair willbe explained briefly: one deals with a porous cup. Apart fromthe tendency that lighter molecules move faster (due to effusionor hindered diffusion), also the liquid with higher density willhave (opposite) tendency to run through the pores and equalizeits level in both parts (the porous cup and the beaker) of thesystem, as a consequence of gravity, i.e. the hydrostatic pressure.

12. It should be noted that Eq. 3 holds strictly for ideal gases. It isexpected to be an excellent approximation for real gases as well,but only an approximation for liquids, due to significantintermolecular interactions.

13. Mohazzabi, P.; Cumaranatunge, L. Can. J. Phys/Rev. Can. Phys.2003, 81, 1121–1129.

˘

´

˘

˘

31

Aust. J. Ed. Chem., 2006, 66,

EXCELLENT RESOURCES FOR SENIOR SECONDARYSCIENCE COURSES AVAILABLE WITHIN AUSTRALIA

The Chemical Education Group of the RACI (SA Branch) has exclusive distributionarrangements within Australia for a number of high quality science magazines,predominantly in Chemistry. The magazines are available on a subscription basis.A few selected books and CD ROMs are also available for purchase.

All of the materials are suitable for teacher and student use.The resources available are:

MagazinesChemMatters Published 4 times per year by the American Chemical Society

Chemistry Review Published 4 times per year for the Chemistry Dept, University of York (UK)

CHEM 13 NEWS Published 9 times per year by the Chemistry Department, University of Waterloo (Canada)

Physics Review Published 4 times per year for the Physics, Electronics and Education Departments,University of York (UK)

Biological Sciences Published 4 times per year for the School of Biological Sciences,Review University of Manchester (UK)

CDROMsChemMatters CD ROM (version 2. 0) contains all issues of the magazine from Feb ’83 to Apr ’98

Journal of Chemical Education CD ROM 2000 contains all J Chem Ed issues from 1997 to 2000

BooksBen Selinger Chemistry in the Marketplace (5th Ed.)

Ben Selinger Why the Watermelon won’t Ripen in your Armpit

By ordering/subscribing through the Chem Ed Group of RACI (SA) rather than through the overseaspublishers of the magazines the hassle and expense of bank drafts in foreign currencies is avoided. Ourmagazine prices are cheaper than direct subscription prices from the publishers.

For prices, catalogues and order forms or further information please contactBob Morton, Publications Coordinator:

Mail: PO Box 749, Blackwood, SA, 5051

Email: rjmorton@adelaide.on. net

Phone: 08 8278 5916

The Royal Australian Chemical Institute (S.A. Branch)Chemical Education GroupPO Box 749Blackwood SA 5051

Ph: (08) 8278 5916Email: rjmorton@adelaide.on.net

A.B.N. 33 087 493 176

32

Aust. J. Ed. Chem., 2006, 66,

Contents

Page

* Teaching modern data analysis with the Royal Australian Chemical Institute’s 5titration competitionBrynn Hibbert

* Children’s alternative conceptions of physical and chemical change obtained 12from historical sources compared with those found in other recent studiesBill Palmer

* Incorporating graduate attributes into a chemistry major 18Trevor C. Brown and Alan M. Wylie

* Alternative demonstrations of slow processes. III: 24A demonstration and video clip showing effusion in liquidsVladimir M. Petrusevski, Marina Monkovic and Metodija Najdoski

* Chemistry Vocabulary: Part 2, Structure Related Terms 27Nittala S. Sarma

* Refereed papers

Cover photographs:"Images from the first year practicum, Utrecht University, the Netherlands."

˘ ´