k4.3 4.0a Practical Experiences Sound

8/13/2019 k4.3 4.0a Practical Experiences Sound

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Download K4.3_4.0a Giving practical experiences in light and sound

Giving Practical experiences light and sound

Most practical work can e experienced ! trainees in school "and will e entirel!

done this wa! on school#ased training courses$. %ri&ar! and secondar! teachers will

all have their 'avourite experi&ents to do with light and sound( so this download has

a 'ew o' the &ore unusual ones( or ones that it is etter 'or trainees to practice awa!'ro& school 'or the 'irst ti&e.

Light

)he paragraph nu&ers re'er to the paragraphs in this unit. *o&e are le't lank.

2.1 Light as a form of energy.

"lank$

2.2. Seeing+

The light box

, shoeox with a see#in hole and windows that can e successivel! opened will help

to show that light needs to shine on o-ects "in the ox$ in order 'or us to e ale to

see the&.

)his can e adapted to &ake a a&era /scura. *earch the we 'or in'or&ation aout

these structures eg http+www.c.co.ukhistor!societ!_cultureartver&eer_ca&era_01.sht&l

amera !bscura "giant pin#hole camera$

%ut !our head into the open end o' the ox2 and cover it with the lack cloth. Makesure it is totall! dark and allow !our e!es to ad-ust. ook at the white sheet o' paper

"the screen$. %oint the pinhole at a window and ask !our partner to hold a nu&er o'

'ingers up to see i' !ou "the person inside$ can see how &an!. )r! holding up other

o-ects( and tr! &oving the& slowl!.

e&e&er that the onl! wa! light could get onto the screen was in through the pin

hole. 5otice that the i&age is the wrong wa! up. )r! increasing the si6e o' the pin#

hole. 7hat happens to i$ the rightness o' the picture and ii$ its sharpness8

)his docu&ent can e 'reel! copied and a&ended i' used 'or educational purposes. 9t &ust not e used 'or co&&ercial gain. )he

author"s$ and we source &ust e acknowledged whether used as it stands or whether adapted in an! wa!.

:Giving practical experiences in light; ,uthored ! Keith oss( 00?@. %age :1; o' :A;
http://www.bbc.co.uk/history/society_culture/art/vermeer_camera_01.shtmlhttp://www.bbc.co.uk/history/society_culture/art/vermeer_camera_01.shtml


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2, large cardoard ox( painted lack inside( with a white ,3 sheet o' paper on one

inside wall opposite a hole the si6e o' a ?p piece on the other. /ne end is open to

allow !our head to e inserted. over the hole with lack paper with di''erent si6ed

holes in the&( starting with one 4&& in dia&eter.

The eye

*tudents should all have a chance to exa&ine a &odel o' the e!e( and even dissect a

ulls e!e.

2.% Shado&s and reflection

Bor K*4 getting pupils to &odel wave 'ronts can e a use'ul experience. 9n these

activities hal' the class should e watching. )he students will line up as a &ilitar!

sCuad( in 3s( ut in open 'or&at and &arch in even step at an angle towards a wall.

)he 'ront row o' 3 students is a wave 'ront( and the colu&ns are the ra!s. achstudent re'lects o'' the wall at an angle eCual to their inco&ing angle( and !ou should

get the new wave 'ront advancing ack o'' the wall. )his can e adapted 'or showing

re'raction "see >.A elow$.

2.' andle#light

9t is worth having a lackened out roo& with a candle urning. *witch on the lights

and students are da66led. ,'terwards when their e!es ad-ust( the candle looks &uch

di&&er.

2.( Sources of light

Diwali lights can &ake an interesting investigation.


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2.) *efraction and dispersion the *ainbo&

)his is where the wave 'ront exercise can reall! ring results. Get the sCuad to

&arch at an angle 'ro& the pla!ground onto grass. ,s each student reaches the grass

the! &ust take steps that are hal' as long as e'ore( ut keep the 'reCuenc! o' the steps

the sa&e. )he e''ect is to slow down the wave 'ront. )he trick is that the direction o'&ove&ent &ust alwa!s e at right angles to the wave 'ront( so the light ends+

)he &ovie can e viewed at+

http+regentsprep.orgegentsph!sicsph!s04cre'ractnde'ault.ht&

9t is etter to have a longer wave 'ront( rather than -ust two as in this ani&ation.

2.+ olour

,n activit! that tests students ideas aout pig&ents in general and the pig&ent(

chloroph!ll in green plants is a nice 'usion o' a traditional ph!sics with a traditional

iological experi&ent suitale 'or K*4.

xtract chloroph!ll 'ro& grass using alcohol( and pour the extract etween two

&icroscope slides glued together on three sides with a glue gun to &ake a narrow

container.

)his eco&es !our 'ilter 'or light 'ro& a ra! ox.

)he ai& is to 'ind out wh! a 'ilter &akes the light green E does it Fd!e the white light

green( or does it Fstop all other colours except green8

9t is hard to tell ! si&pl! placing the 'ilter in 'ront o' the la&p( ut i' !ou use a

pris& to get a spectru& then put the 'ilter in 'ront "either e'ore or a'ter the pris&$

!ou will 'ind that the pig&ent asors the red and lue light and onl! lets the green

through.



http://regentsprep.org/Regents/physics/phys04/crefractn/default.htmhttp://regentsprep.org/Regents/physics/phys04/crefractn/default.htm


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)his shows that+

"%h!sics$ pig&ents asor so&e colours 'ro& white light( onl! letting the others pass.

"Hiolog!$ chloroph!ll asors red and lue light. 7e think o' plants eing associated

withgreenlight( ut the! are using the blueand redparts o' the suns spectru& to

drive photos!nthesis.

Light

)he paragraph nu&ers re'er to the paragraphs in download 3.1 on sound. *o&e are

le't lank. 7e have used the sa&e paragraph headings as in light( aove( to show the

si&ilarities and contrasts.

%.1 Sound as a form of energy

Getting students to look at the power rating "in watts$ o' speakers will help the&

realise how little energ! is needed to &ade ver! loud noises.%.2 ,earing sound

, good trick is to tell the students to do so&ething "such as putting up their hands(

or stand up$ using a language that &ost will not understand. )hen see& surprised the!

didnt do as the! were told. *ounds not onl! have to reach the ear( ut the rain has

then to &ake sense o' the& using previous &e&ories.

%.% Sound shado&s and reflections "echoes$

Iou can get a good &easure o' the speed o' sound ! standing 1?0 &etres 'ro& a 'lat

uilding "eg in the school grounds$ and &ake a clap with two pieces o' wood. Iouwill hear an echo( ut ti&ing it is ver! inaccurate. 9' !ou clap again so that !ou set up

a regular clapJ echoJ clapJ echo !ou can now ti&e 30 clap#echoes and thus work

out the speed o' sound.

%.' Sound intensity and logarithmic scales

7ork on logarith&ic scales will e necessar! 'or all ut the ver! &athe&aticall!

&inded student.

%.( Sources of Sound

)he di''erence in loudness o' tapping a ruler held in the teeth "sound goes via !our-awone$ and in the lips "sound goes via the air$ is a si&ple ut dra&atic illustration

o' the wa! sound travels+ si&ilarl! tapping a pencil on the ench with !our ear either

resting on the ench or -ust aove it. 7e hear our own voices &ostl! through our

ones and inner ear( so whispering whist cupping !our hands to &ake a path 'ro&

!our &outh round to !our ear allows !ou to hear !our voice as other hear !ou.





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%.) *efraction- dispersion and the oppler effect.

)hese static pictures can e &ade o' separate /L)s and &oved to show the e''ect o'

the source o' sound travelling eventuall! at supersonic speeds. )here are several

ani&ations availale on the we. )he! can e de&onstrated on a large ripple tank too.

Stationary/oving slo&er than the

&aves

/oving faster than the

&aves

nor&al Doppler e''ect How wave or sonic oo&

+$ Sound and /usic musical 0colour

, neat de&onstration o' har&onics can e per'or&ed with a long length o' ruer

tuing. /ne student hold one end and !ou then rotate !our end gentl! to get hal' a

wave "as in "doh$ in the diagra&$. H! rotating twice as 'ast !ou can get the octave

. H! practising( and having the tuing tight enough !ou can get all the har&onics up

to . "rotation is easier than wiggling up and down E note that we are representing

sound waves here( and aove with the water analog!( as transverse waves( and theuse o' a slink! to show longitudinal waves "co&pression and rare'action$ will e

necessar!$

5ow get a length o' hosepipe "3#? &etres$ and 'it a plastic 'unnel to one end( and t

rass pla!ers &outhpiece to the other. ,sk a rass pla!er to show the sa&e e''ect !

getting the air in the hosepipe to virate. 5or&all! !ou will start at around 4 or ? hal'

waves( so !ou can easil! get G H and . ,'ter that !ou will hear the

nor&al notes o' the scale as the horn pla!s ( D etc.

)he whole thing can now e repeated using an oscilloscope and signal generator. %la!

the note 'ro& 100 hert6( then >00 to show the octave. 5ow pla! 300 and 400hert6 tohear the do&inant and the next octave. Binall! ?00(. A00.( N00( and 00 to get the

roken cord up to the next octave.



:Giving practical experiences in light; ,uthored ! Keith oss( 00?@. %age :?; o' :A;


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%. Sound &ords

Getting student teachers to look 'or the origin o' the words the! want their pupils to

use is an i&portant activit!. 9t helps children see that the word has &eaning and is not

-ust a rand net 'oreign word to learn.

)he scienti'ic sound#related words that we use co&e 'ro& the atin audireto hear

"audience( audit( aural( audio( audition etc$( 'ro& the atin sonareto sound "sonar(

sonata( sonic( sonnet( consonant "sounding with$ etc$ and the Greekphone a sound

"gra&ophone( telephone( phone&e( phonetic$.



:Giving practical experiences in light; ,uthored ! Keith oss( 00?@. %age :A; o' :A;

k4.3 4.0a Practical Experiences Sound

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