Introduction to Science

Introduction to SciencePhysical Science Chapter 11Physical Science Chapter 1The Nature of ScienceHow science takes placeThe branches of scienceScientific laws and theoriesThe Way Science WorksScience skills and scientific methodUnits of measurement and unit conversionsOrganizing DataPresenting scientific data using graphs and tablesWriting numbers in scientific notationUsing significant figuresPhysical Science Chapter 12Chapter OutlineThe knowledge and skills gained in unit will serve as a foundation for the study of science.Physical Science Chapter 13Why it mattersMyth: learning is the passive transfer of knowledgeFact: learning is dynamic and involves continuously questioning informationMyth: science is a static, faithful copy of the worldFact: science is a human construction based on the most logical interpretation of experiment and theoryPhysical Science Chapter 14Myths vs. FactsDo you understand each of the graphic organizers on page 4?Which type do you like best?Physical Science Chapter 15DiscussHow Science Takes PlaceHow do scientists explore the world?

A scientist may perform experiments to find a new aspect of the natural world, to explain a known phenomenon, to check the results of other experiments, or to test the predictions of current theories.

6Physical Science Chapter 1How Science Take Place, continuedScientists investigate.

Scientists plan experiments.

Scientists observe.

Scientists always test the results.7Physical Science Chapter 1The Branches of ScienceHow are the many types of science organized?

Most of the time, natural science is divided into biological science, physical science and Earth science.

science: the knowledge obtained by observing natural events and conditions in order to discover facts and formulate laws or principles that can be verified or tested8Physical Science Chapter 1The Branches of Science, continuedThe branches of science work together.biological science: the science of living thingsbotany, ecologyphysical science: the science of matter and energychemistry: the science of matter and its changesphysics: the science of forces and energyearth science: the science of the Earth, the atmosphere, and weathergeology, meteorology9Physical Science Chapter 1Visual Concept: Natural Science10Physical Science Chapter 1The Branches of Science, continuedScience and technology work together.

pure science: the continuing search for scientific knowledge

Advances in science and technology depend on each other.

technology: the application of science for practical purposes11Physical Science Chapter 1Scientific Laws and TheoriesWhat are scientific theories, and how are they different from scientific laws?

Theories explain why something happens, laws explain how something works.

law: a descriptive statement or equation that reliably predicts events under certain conditions

theory: a system of ideas that explains many related observations and is supported by a large body of evidence acquired through scientific investigation12Physical Science Chapter 1Scientific Laws and Theories, continuedExperimental results support laws and theories.

Scientific theories are always being questioned and examined. To be valid, a theory must:

explain observations

be repeatable

be predictable13Physical Science Chapter 1Scientific Laws and Theories, continuedMathematics can describe physical events.

qualitative statement: describes something with words

quantitative statement: describes something with mathematical equations14Physical Science Chapter 1Scientific Laws and Theories, continuedTheories and laws are always being tested.

Models can represent physical events.

model: a representation of an object or event that can be studied to understand the real object or eventScientists use conceptual, physical, and computer models to study objects and events.

We use models in our everyday lives.15Physical Science Chapter 1What are the two branches of physical science?What are three types of models used by scientists?Compare and contrast a scientific law and a scientific theory.Physical Science Chapter 116DiscussScience SkillsHow can I think and act like scientist?

Identifying problems, planning experiments, recording observations, and correctly reporting data are some of the most important science skills.

Scientists approach a problem by thinking logically.

17Physical Science Chapter 1Science Skills, continuedCritical thinking helps solve problems logically.

critical thinking: the ability and willingness to assess claims critically and to make judgments on the basis of objective and supported reasons

Scientists use scientific methods to solve problems.

scientific method: a series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions

The scientific methods are general description of scientific thinking rather than an exact path for scientists to follow.

18Physical Science Chapter 1Science Skills, continuedScientists test hypotheses.

hypothesis: a possible explanation or answer that can be tested

Scientists test a hypothesis by doing a controlled experiment.

controlled experiment: an experiment in which the variables that could affect the experiment are kept constant (controlled) except for the one that you want to measure

variable: a factor that changes in an experiment in order to test a hypothesis19Physical Science Chapter 1Science Skills, continuedExperiments test ideas.

No experiment is a failure.

The results of every experiment can be used to revise the hypothesis or plan tests of a different variable.

Peer-reviewed research: research that has been reviewed by other scientists20Physical Science Chapter 1Science Skills, continuedScientists use special tools.

There are many tools used by scientists for making observations, including

telescopes

spectroscopes

particle accelerators

21Physical Science Chapter 1Units of MeasurementHow do scientists measure things?

Scientists use standard units of measure that together form the International System of Units, or SI.

22Physical Science Chapter 1Units of Measurement, continuedSI units are used for consistency.SI has seven base units.

derived units: combinations of the base units

23Physical Science Chapter 1

SI (Le Systme Internationale dUnits)

24Physical Science Chapter 1Units of Measurement, continuedSI prefixes are for very large and very small measurements.The prefixes are multiples of ten.

SI prefixes for large measurements

25Physical Science Chapter 1Units of Measurement, continuedSI prefixes for small measurements

26Physical Science Chapter 1Units of Measurement, continuedMeasurements quantify your observations.

length: a measure of the straight-line distance between two points

mass: a measure of the amount of matter in an object

volume: a measure of the size of a body or region in three-dimensional space

weight: a measure of the gravitational force exerted on an object27Physical Science Chapter 1When might a scientist change a hypothesis?A student needs to measure the volume of a liquid. What tool could the student use?Look at Figure 1 on page 14. Answer the question in the caption.DiscussPhysical Science Chapter 128September 09Physical Science chapter 229ConversionsMethod that always works:Write conversion factors as fractions that equal 1Multiply by fractions createdRepeat until you get the units you wantSeptember 09Physical Science chapter 230ExampleUsing the conversion factor 1 inch = 2.54 cm, convert 8.5 inches to cm.Write conversion factor as fractions

September 09Physical Science chapter 231Conversion factor fractions both equal 1We can multiply by them without changing the valueTo decide which fraction to use, look at units of what is being convertedSeptember 09Physical Science chapter 232Given: 8.5 inchesWe want inches to cancel out, so it needs to be in the denominator

September 09Physical Science chapter 233ExampleUsing the conversion factor 1 m = 100 cm, convert 3.2 m to cm.Write conversion factor as fractions

September 09Physical Science chapter 234Given: 3.2 mWe want m to cancel out, so it needs to be in the denominator

September 09Physical Science chapter 235SI shortcutMeasurement in SI is based on multiples of 10.To multiply or divide by multiples of 10, you just move the decimal point.September 09Physical Science chapter 236Using the prefix tableCount the number of columns you move in the table.Move the decimal point the same number of places and in the same directionIf converting from a smaller unit to a larger one (like cm to km), move the decimal to the left. (remember to Larger; to Left)If converting from a larger unit to a smaller one (like kg to mg), move the decimal to the right.September 09Physical Science chapter 237ExampleConvert 3.2 m to cmMove two columns to the right.Move decimal point two places to the right.320 cmHow to show your work:September 09Physical Science chapter 238ExampleConvert 500 mg to kgMove six columns to the left.Move decimal point six places to the left.0.0005 kgSeptember 09Physical Science chapter 239You TryConvert 5 dm to mMove one column to the left.Move decimal point one place to the left.0.5 mSeptember 09Physical Science chapter 240You TryConvert 567 cm to mmMove one column to the right.Move decimal point one place to the right.5670 mmPresenting Scientific DataWhy is organizing data an important science skill?

Because scientists use written reports and oral presentations to share their results, organizing and presenting data are important science skills.41Physical Science Chapter 1Presenting Scientific Data, continuedLine graphs are best for continuous change.

dependent variable: values depend on what happens in the experiment

Plotted on the x-axis

independent variable: values are set before the experiment takes place

Plotted on the y-axis42Physical Science Chapter 1Line Graph

43Physical Science Chapter 1Presenting Scientific Data, continuedBar graphs compare items.

A bar graph is useful for comparing similar data for several individual items or events.

A bar graph can make clearer how large or small the differences in individual values are.44Physical Science Chapter 1Bar Graph

45Physical Science Chapter 1Presenting Scientific Data, continuedPie graphs show the parts of a whole.

A pie graph is ideal for displaying data that are parts of a whole.

Data in a pie chart is presented as a percent.Composition of a Winter Jacket

46Physical Science Chapter 1Writing Numbers in Scientific NotationHow do scientists handle very large and very small numbers?

To reduce the number of zeros in very big and very small numbers, you can express the values as simple numbers multiplied by a power of 10, a method called scientific notation.

scientific notation: a method of expressing a quantity as a number multiplied by 10 to the appropriate power47Physical Science Chapter 1Writing Numbers in Scientific Notation, continuedSome powers of 10 and their decimal equivalents are shown below.

103 = 1,000102 = 100101 = 10100 = 110-1 = 0.110-2 = 0.0110-3 = 0.00148Physical Science Chapter 1Math SkillsWriting Scientific Notation The adult human heart pumps about 18,000 L of blood each day. Write this value in scientific notation.

1. List the given and unknown values.Given: volume, V = 18,000 LUnknown: volume, V = ? 10? L49Physical Science Chapter 1Math Skills, continued2. Write the form for scientific notation.

V = ? 10? L

3. Insert the known values into the form, and solve.Find the largest power of 10 that will divide into the known value and leave one digit before the decimal point.

You get 1.8 if you divide 10,000 into 18,000 L.

18,000 L can be written as (1.8 10,000) L50Physical Science Chapter 1Math Skills, continuedThen, write 10,000 as a power of 10.

10,000 = 104

18,000 L can be written as 1.8 104 L

V = 1.8 104 L51Physical Science Chapter 1Write 0.0254 m in scientific notation.

ExamplePhysical Science Chapter 152Write 6,210 km in scientific notation.

You tryPhysical Science Chapter 153Write 2.71 x 10-9 kg in long form.Write 6.28 x 107 m in long form.

ExamplePhysical Science Chapter 154Write 6.28 x 107 m in long form.

You tryPhysical Science Chapter 155Writing Numbers in Scientific NotationUse scientific notation to make calculations.

When you use scientific notation in calculations, you follow the math rules for powers of 10.

When you multiply two values in scientific notation, you add the powers of 10.

When you divide, you subtract the powers of 10.56Physical Science Chapter 1Math SkillsUsing Scientific Notation Your county plans to buy a rectangular tract of landmeasuring 5.36 x 103 m by 1.38 x 104 m to establish anature preserve. What is the area of this tract in squaremeters?

1. List the given and unknown values.Given: length (l )= 1.38 104 mwidth (w) = 5.36 103 mUnknown: area (A) = ? m257Physical Science Chapter 1Math Skills, continued2. Write the equation for area.A = l w

3. Insert the known values into the equation, and solve.A = (1.38 104 m) (5.36 103 m)Regroup the values and units as follows.A = (1.38 5.36) (104 103) (m m)When multiplying, add the powers of 10.A = (1.38 5.35) (104+3) (m m)A = 7.3968 107 m2 A = 7.40 107 m258Physical Science Chapter 1Using Significant FiguresHow can you tell the precision of a measurement?

Scientists use significant figures to show the precision of a measured quantity.

precision: the exactness of a measurement

significant figure: a prescribed decimal place that determines the amount of rounding off to be done based on the precision of the measurement

59Physical Science Chapter 1Using Significant Figures, continuedPrecision differs from accuracy.

accuracy: a description of how close a measurement is to the true value of the quantity measured

60Physical Science Chapter 1Accuracy and Precision, Part 1

61Physical Science Chapter 1Accuracy and Precision, Part 2

62Physical Science Chapter 1Using Significant Figures, continuedRound your answers to the correct significant figures.

When you use measurements in calculations, the answer is only as precise as the least precise measurement used in the calculation.

The measurement with the fewest significant figures determines the number of significant figures that can be used in the answer.

63Physical Science Chapter 1Math SkillsSignificant Figures Calculate the volume of a room that is 3.125 m high, 4.25 m wide, and 5.75 m long. Write the answer with the correct number of significant figures.

1. List the given and unknown values.Given: length, l = 5.75 mwidth, w = 4.25 mheight, h = 3.125 mUnknown: volume, V = ? m364Physical Science Chapter 1Math Skills, continued2. Write the equation for volume.V = l w h

3. Insert the known values into the equation, and solve.V = 5.75 m 4.25 m 3.125 mV = 76.3671875 m3

The answer should have three significant figures, because the value with the smallest number of significant figures has three significant figures.V = 76.4 m365Physical Science Chapter 1Perform the following calculation and write the answer with the correct number of significant figures.

ExamplePhysical Science Chapter 166Perform the following calculation and write the answer with the correct number of significant figures.

You tryPhysical Science Chapter 167