Chapter 1: Nature of Chapter 1: Nature of ScienceScience

• What is a scientist and what What is a scientist and what does he do?does he do?– Scientists investigateScientists investigate– Scientists plan experimentsScientists plan experiments– Scientists observeScientists observe– Scientists test resultsScientists test results– SCIENTISTS ASK GOOD SCIENTISTS ASK GOOD

QUESTIONS!QUESTIONS!

Pure Science vs. Pure Science vs. TechnologyTechnology

•Pure Science is scientific Pure Science is scientific knowledge gained by knowledge gained by observation and experiment.observation and experiment.

•Technology is the application Technology is the application of pure science to meet of pure science to meet human needs.human needs.

Scientific TheoryScientific Theory

• A scientific theory is a tested, A scientific theory is a tested, explanation of a natural event. explanation of a natural event. [Theories have [Theories have notnot been proven] been proven]– A theory must explain observations A theory must explain observations

simply and clearly.simply and clearly.– Experiments that illustrate the Experiments that illustrate the

theory must be repeatable.theory must be repeatable.– You must be able to predict from You must be able to predict from

the theory.the theory.

Scientific LawScientific Law

• A scientific law is a description A scientific law is a description of a natural event. of a natural event. [Laws [Laws havehave been proven]been proven]– Newton’s law of gravityNewton’s law of gravity– Newton’s laws of motionNewton’s laws of motion– Hooke’s lawHooke’s law– Kepler’s laws of planetary motionKepler’s laws of planetary motion– Etc.Etc.

Section 1.1 Review:Section 1.1 Review:

• Explain how science and Explain how science and technology depend on each technology depend on each other.other.

• How does a scientific law differ How does a scientific law differ from a theory?from a theory?

• Pick a common phenomenon and Pick a common phenomenon and develop a theory about it, what develop a theory about it, what kind of experiment could you do kind of experiment could you do to test the theory?to test the theory?

Section 1.2 Section 1.2 The Way Science WorksThe Way Science Works

• Critical thinking is a basic skill of a Critical thinking is a basic skill of a scientist. It is applying logic and reason to scientist. It is applying logic and reason to observations and conclusions.observations and conclusions.

• The scientific method is a series of logical The scientific method is a series of logical steps to follow in order to solve a problem steps to follow in order to solve a problem or answer a question. (pg. 13 fig 1-12)or answer a question. (pg. 13 fig 1-12)

Scientific Method [5 Scientific Method [5 steps]steps]•Make an observationMake an observation

•Form an hypothesisForm an hypothesis

•Make predictionsMake predictions

•Test the hypothesisTest the hypothesis

•Draw a conclusionDraw a conclusion

Systeme International d' Unites – SISysteme International d' Unites – SIMeasurement System Measurement System

Base Units of SI System (total of 7) (total of 7)

1.1.Length – Meter, mLength – Meter, m

2.2.Mass – Kilogram, kgMass – Kilogram, kg

3.3.Time – Second, sTime – Second, s

4.4.Temperature – Kelvin, KTemperature – Kelvin, K

5.5.Electric current – ampere, AElectric current – ampere, A

6.6.Amount of substance – mole, molAmount of substance – mole, mol

7.7.Luminous intensity – candela, cdLuminous intensity – candela, cd

Systeme International d' Unites – SISysteme International d' Unites – SIMeasurement System Measurement System

Derived Units of SI System (hundreds) (hundreds)

• Force – Newton, NForce – Newton, N

• Area – Square meters, mArea – Square meters, m22

• Volume (liquid)– Liter, L.Volume (liquid)– Liter, L.

• Velocity – meters/second, m/sVelocity – meters/second, m/s

• Acceleration - meters/second/second, m/sAcceleration - meters/second/second, m/s22

• Pressure- N/mPressure- N/m22

Examples of SI Measurement Examples of SI Measurement System unitsSystem units

• Length – meter, mLength – meter, m• Force or weight – Newton, NForce or weight – Newton, N• Mass – kilogram, kgMass – kilogram, kg• Area – mArea – m22

• Volume – mVolume – m33

• Density – g/cmDensity – g/cm33

• Time – second, sTime – second, s• Temperature – degrees Celsius, Temperature – degrees Celsius, ooC C

Examples of English Examples of English Measurement System unitsMeasurement System units

• Length – feet, ftLength – feet, ft• Force or weight – pounds, lbsForce or weight – pounds, lbs• Area – square feet, ftArea – square feet, ft22

• Volume – cubic feet, ftVolume – cubic feet, ft33

• Density – pound per cubic feet, lb/ftDensity – pound per cubic feet, lb/ft33

• Time – seconds, sTime – seconds, s• Temperature – degrees Fahrenheit, Temperature – degrees Fahrenheit, ooF F • Etc.Etc.

Scientific NotationScientific Notation

In many branches of science, some numbers are In many branches of science, some numbers are very small, while others are quite large. To very small, while others are quite large. To conveniently express these numbers, scientists conveniently express these numbers, scientists use a type of shorthand called use a type of shorthand called scientific notationscientific notation to express the number as a multiplier and a power to express the number as a multiplier and a power of 10.of 10.

0.00000325 = 3.25 x 100.00000325 = 3.25 x 10-6-6

422,000,000,000,000 = 4.22 x 10422,000,000,000,000 = 4.22 x 101414

Significant FiguresSignificant Figures

• For numbers with no decimal point, start from For numbers with no decimal point, start from the “atlantic” right hand side and count all the “atlantic” right hand side and count all digits beginning with the first non-zero digit.digits beginning with the first non-zero digit.– Ex: 45000 has two sig. figs.Ex: 45000 has two sig. figs.

• For numbers with a decimal point, start from For numbers with a decimal point, start from the “pacific” left hand side and count all digits the “pacific” left hand side and count all digits beginning with the first non-zero digit.beginning with the first non-zero digit.

Scientific NotationScientific Notation

• Scientific Notation: a value written as a Scientific Notation: a value written as a simple number multiplied by a power simple number multiplied by a power of 10.of 10.– Ex: 10000 = 10Ex: 10000 = 1044 0.001 = 100.001 = 10-3-3

– Why is one positive and the other Why is one positive and the other negative?negative?

– Very large #’s are positive and very small Very large #’s are positive and very small #’s are negative.#’s are negative.

Metric PrefixesMetric PrefixesPrefixPrefix SymbolSymbol MeaningMeaning

kilo-kilo- kk 10001000

hecto-hecto- hh 100100

deka-deka- dada 1010

Base Unit-----------------------------------Base Unit-----------------------------------

deci-deci- dd 0.10.1

centi-centi- cc 0.010.01

milli-milli- mm 0.0010.001

micro-micro- mm 0.0000010.000001

nano-nano- nn 0.0000000010.000000001

Meaningful Metric PrefixesMeaningful Metric PrefixesPrefixPrefix SymbolSymbol MeaningMeaningtera-tera- TT 1000000000000 or 101000000000000 or 101212

giga-giga- GG 1000000000 or 101000000000 or 1099

mega-mega- MM 1000000 or 101000000 or 1066

kilo-kilo- kk 1000 or 101000 or 1033

milli-milli- mm 0.001 or 100.001 or 10-3-3

micro-micro- 0.000001 or 100.000001 or 10-6-6

nano-nano- nn 0.000000001 or 100.000000001 or 10-9-9

pico-pico- pp 0.000000000001 or 100.000000000001 or 10-12-12

Converting temperatureConverting temperature

• Conversion of Fahrenheit to CelsiusConversion of Fahrenheit to CelsiusooC = 5/9 [C = 5/9 [ooF - 32]F - 32]

• Conversion of Celsius to FahrenheitConversion of Celsius to FahrenheitooF = [9/5 x F = [9/5 x ooC] + 32C] + 32

Section 1.2 cont..Section 1.2 cont..

• A conversion factor is used to convert A conversion factor is used to convert between units.between units.

• Ex: How many centimeters are in 1.85 Ex: How many centimeters are in 1.85 inches?inches?

1.85 in x [2.54 cm/1 in]1.85 in x [2.54 cm/1 in]

4.70 cm4.70 cm

Ex: How many Ex: How many

Section 1.2 cont…Section 1.2 cont…• How to set up a conversion factor:How to set up a conversion factor:

• #1: Always write what you are given #1: Always write what you are given FIRST!FIRST!

• #2: Put what you are looking for on top of #2: Put what you are looking for on top of the conversion line.the conversion line.

• #3: Put what you are trying to cancel out on #3: Put what you are trying to cancel out on the bottom of the conversion line.the bottom of the conversion line.

Conversion Factor Conversion Factor ProcessProcess• Ex: Write 550 millimeters as Ex: Write 550 millimeters as

metersmeters

• #1: given: 550 millimeters#1: given: 550 millimeters

• #2: looking for meters#2: looking for meters

• #3: want to cancel millimeters#3: want to cancel millimeters

• 550 mm x 1 m/1000 mm550 mm x 1 m/1000 mm

• Calculate: 550 x 1 / 1000 = 0.55 mCalculate: 550 x 1 / 1000 = 0.55 m

Conversion PracticeConversion Practice• Convert the following:Convert the following:

– 1.6 kilograms to grams1.6 kilograms to grams

– 2500 milligrams to kilograms2500 milligrams to kilograms

– 0.4 millimeters to 0.4 millimeters to micrometersmicrometers

– 2800 millimoles to moles2800 millimoles to moles

– 6.1 amperes to milliamperes6.1 amperes to milliamperes

1600 g1600 g

.0025 Kg.0025 Kg

400 400 mm

2.8 mol2.8 mol

6100 mA6100 mA

Section 1.2 Making Section 1.2 Making MeasurementsMeasurements• There are many observations that There are many observations that

rely on quantative measurements. rely on quantative measurements. The most basic scientific The most basic scientific measurements generally answer measurements generally answer how big, how much, or how much how big, how much, or how much time.time.

• We use length, mass, time, and We use length, mass, time, and volume as quantative volume as quantative measurements in labs.measurements in labs.

• Remember: Remember: – Length = metersLength = meters– Mass = gramsMass = grams– Volume = liters or cubic centimeters Volume = liters or cubic centimeters

cmcm33

Organizing DataOrganizing Data

• There are several ways to organize lab data.There are several ways to organize lab data.

– Data Chart: Good way of keeping track Data Chart: Good way of keeping track of something over time or making several of something over time or making several readings on a topic. Usually done as raw readings on a topic. Usually done as raw data.data.

– Graphs: A good way to organize your Graphs: A good way to organize your raw data and show trends, inferences, or raw data and show trends, inferences, or results.results.

GraphsGraphs

• There are several types of There are several types of graphs.graphs.– Line graph: shows change over timeLine graph: shows change over time– Bar graph: good for comparing data Bar graph: good for comparing data

for several individual items or for several individual items or eventsevents

– Pie chart: ideal for displaying data Pie chart: ideal for displaying data that are parts of a wholethat are parts of a whole

Line GraphLine Graph• Independent variable: goes Independent variable: goes

on the x axis. That is the on the x axis. That is the bottom of the graph. Here bottom of the graph. Here the time in days is the the time in days is the independent variable. This independent variable. This variable is determined by variable is determined by the experimenter.the experimenter.

• Dependent variable: what is Dependent variable: what is changing in the experiment. changing in the experiment. This is not determined by This is not determined by the experimenter.the experimenter.

Bar GraphBar Graph

What you’re comparing goes on the x axisWhat you’re comparing goes on the x axis

Pie ChartPie Chart