ch. 1 - the nature of science defining science problem-solving scientific method experimental...
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Ch. 1 - The Nature of Science
Defining Science
Problem-Solving
Scientific Method
Experimental Design
Section 1: The Methods of Science
A. Defining Science
Pure Science research that adds to the body of
scientific knowledge has no practical use
Applied Science (Technology) the practical application of scientific
knowledge
A. Defining Science
PURE
human genetics
polymer science
atomic theory
study of the human ear
APPLIED
DNA fingerprinting
Lycra® spandex
nuclear weapons
hearing aids
A. Defining Science
Life Science the study of living organisms
Earth Science the study of Earth and space
Physical Science the study of matter and energy chemistry & physics
B. Problem-Solving
1. Identify the problem. What do you know? What do you need to know?
2. Plan a strategy. Look for patterns. Break the problem into smaller steps. Develop a model.
B. Problem-Solving
3. Execute your plan.
4. Evaluate your results. Did you solve the problem? Is your answer reasonable?
Identify - Plan - Execute - Evaluate
C. Scientific Method
Hypothesis - testable prediction
Theory - explanation of “why” based on many observations &
experimental results
Scientific Law - prediction of “what” describes a pattern in nature
C. Scientific Method
Theories and laws are well-accepted by scientists, but...
They are revised when new information is discovered.
THEY ARE NOT SET IN STONE!
C. Scientific Method
1. Determine the problem.
2. Make a hypothesis.
3. Test your hypothesis.
4. Analyze the results.
5. Draw conclusions.
C. Scientific Method
1. Determine the problem. When the Titanic sank, what happened to
the water level on shore?
2. Make a hypothesis. The water level rose. The water level dropped. The water level stayed the same.
C. Scientific Method
3. Test your hypothesis. How could we test our hypothesis?
4. Analyze the results. What happened during our test?
5. Draw conclusions. Was our hypothesis correct? Is further testing necessary?
D. Experimental Design
Experiment - organized procedure for testing a hypothesis
Key Components: Control - standard for comparison Single variable - keep other factors
constant Repeated trials - for reliability
D. Experimental Design
Types of Variables
Independent Variable adjusted by the experimenter what you vary
Dependent Variable changes in response to the indep.
variable what you measure
D. Experimental Design
Hypothesis:
Storing popcorn in the freezer makes it pop better.
Control:
Popcorn stored at room temp.
D. Experimental Design
Single variable:
Storage temperature
Constants:
Popcorn brand
Freshness
Storage time
Popper
D. Experimental Design
Independent Variable:
Storage temperature
Dependent Variable:
Number of unpopped kernels
Section 2: Standards of Section 2: Standards of MeasurementMeasurement
Units and StandardsUnits and Standards
Standard:Standard: an exact quantity that is used for an exact quantity that is used for comparisoncomparison International Bureau of Weights and MeasuresInternational Bureau of Weights and Measures
Measurement SystemsMeasurement Systems EnglishEnglish
Pounds, ounces, gallons, etc.Pounds, ounces, gallons, etc.
MetricMetric ( (SISI, , from the Frenchfrom the French, Le Systeme Internationale , Le Systeme Internationale d’Unites)d’Unites) Meters, kilograms, KelvinsMeters, kilograms, Kelvins
– Preferred for science because it’s based on multiples Preferred for science because it’s based on multiples of tenof ten
– Accepted and understood throughout the worldAccepted and understood throughout the world
Metric Base UnitsMetric Base UnitsQUANTITY BASE
UNIT SYMBOL EXAMPLE
length 1 meter m 1 baseball bat = 1 meter
mass 1 kilogram kg 1 person = 65 kilograms
time 1 second s you read this in 1 second
electric current 1 ampere A hairdryers use 8 amps of current
temperature 1 Kelvin K Water boils at 373K
amount 1 mole mol 18 g of H2O = 1 mole of water
candela 1 candela cd Fog lights can be 1000 cd
METRIC PREFIXES
Prefix Symbol Decimal Sample Expression
Mega M 1 000 000 1 Mm = 1 000 000 m
Kilo k 1 000 1 kg = 1000 g
Hecto h 100 1 hm = 100 m
Deca da 10 1 das = 10 s
*BASE UNIT* m, s, K, mol, g **1 base unit ** *************
Deci d 0.1 1 dmol = 0.1 mol
Centi c 0.01 1 cm = 0.01 m
Milli m 0.001 1 mg = 0.001 g
Micro μ 0.000 001 1 μK = 0.000 001 K
One Step Metric ConversionsOne Step Metric Conversions Convert between a prefix and a base Convert between a prefix and a base
unitunit Conversion factors relate prefixes and Conversion factors relate prefixes and
base units base units
Example: How many centimeters are Example: How many centimeters are equal to 2.5 meters?equal to 2.5 meters?
Plan: Use conversion (1 cm = 0.01m)Plan: Use conversion (1 cm = 0.01m) Math: Math:
givenunits
wantedunits
1. Multiply by what’s on the top
2. Divide by what’s on the bottom
3. Diagonal units cancel
1 conversion means 1 “fence
post!”
2.5 m 1 cm = 250 cm 0.01 m
Sample problems:Sample problems: How many kilometers are equal to 750 000 How many kilometers are equal to 750 000
meters? meters? (1 km = 1000 m)(1 km = 1000 m)
How many seconds are equal to 350 000 000 How many seconds are equal to 350 000 000 microseconds? (1 microseconds? (1 µs = 0.000 001 s)µs = 0.000 001 s)
How many millimoles are equal to 15 moles? How many millimoles are equal to 15 moles? (1 mmol = 0.001 mol)(1 mmol = 0.001 mol)
How many Kelvin are equal to 300 decaKelvin? How many Kelvin are equal to 300 decaKelvin? (1 daK = 10 K)(1 daK = 10 K)
Two Step Metric ConversionsTwo Step Metric Conversions Convert between 2 prefixesConvert between 2 prefixes Conversion factors relate prefixes and Conversion factors relate prefixes and
base units base units
Example: How many centimeters are Example: How many centimeters are equal to 2.5 kilometers?equal to 2.5 kilometers?
Plan: Use conversions Plan: Use conversions (1 cm = 0.01m) and (1 km = (1 cm = 0.01m) and (1 km = 1000 m)1000 m)
Math: Math:
givenunits
wantedunits
1. Multiply by everything on top2. Divide by everything on bottom3. Diagonal units cancel
2 conversions means 2 “fence posts!”
2.5 km 1000 m 1 cm = 250 000 cm 1 km 0.01 m
Sample problems:Sample problems: How many kilometers are equal to 750 000 How many kilometers are equal to 750 000
decimeters? decimeters? (1 dm = 0.1 m) and (1 km = 1000 m) (1 dm = 0.1 m) and (1 km = 1000 m)
How many Megaseconds are equal to 350 000 000 How many Megaseconds are equal to 350 000 000 microseconds? microseconds? (1 (1 µs = 0.000 001 s) µs = 0.000 001 s) and (1 Ms = 1 000 000 s) and (1 Ms = 1 000 000 s)
How many millimoles are equal to 1.5 kilomoles?How many millimoles are equal to 1.5 kilomoles?(1 kmol = 1000 mol) and (1 mmol = 0.001 mol)(1 kmol = 1000 mol) and (1 mmol = 0.001 mol)
How many centiKelvin are equal to 300 decaKelvin? How many centiKelvin are equal to 300 decaKelvin? (1 daK = 10 K) and (1 cK = 0.01 K)(1 daK = 10 K) and (1 cK = 0.01 K)
Derived UnitsDerived Units Derived units are not measured directlyDerived units are not measured directly
They are the result of a calculation involving They are the result of a calculation involving several measurementsseveral measurements VolumeVolume DensityDensity
Units are combinations of the units used in making Units are combinations of the units used in making the measurementsthe measurements Volume of a regularly-shaped object: mVolume of a regularly-shaped object: m33, cm, cm33
Volume of liquid: mL, LVolume of liquid: mL, L Density of a solid:Density of a solid:
Density of a liquid: Density of a liquid: 3cm
g
mL
g
Volume DeterminationVolume Determination Volume:Volume: The amount of space an object occupies The amount of space an object occupies
OROR the amount of space available inside of an the amount of space available inside of an objectobject
Regularly shaped object:Regularly shaped object:
V = L x W x H = __cmV = L x W x H = __cm33 or __m or __m33
Irregularly shaped object: Water Irregularly shaped object: Water DisplacementDisplacement Place object in a known volume of waterPlace object in a known volume of water Determine the difference in water levels after Determine the difference in water levels after
object is in the waterobject is in the water Convert to appropriate units (Convert to appropriate units (1 mL = 1 cm1 mL = 1 cm33))
Density DeterminationDensity Determination
Density:Density: the expression for the amount of the expression for the amount of matter contained in a certain volumematter contained in a certain volume
Formula:Formula:
Volume
massDensity
3cm
gmL
g m
D V
Section 3: Communicating with Graphs
A. Types of Graphs
Line Graph
shows the relationship between 2 variablesD
epen
den
t V
aria
ble
Independent Variable
A. Types of Graphs
Bar Graph
shows information collected by counting
A. Types of Graphs
Pie Graph
shows distribution of parts within a whole quantity
B. Graphing & DensityM
ass
(g)
Volume (cm3)
Δx
Δyslope D
V
M