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 Measurement

Units and Standards  Standard: an exact quantity that is used for comparison  International Bureau of Weights and Measures  Measurement Systems  English  Pounds, ounces, gallons, etc.  Metric (SI, from the French, Le Systeme Internationale d’Unites)  Meters, kilograms, Kelvins –Preferred for science because it’s based on multiples of ten –Accepted and understood throughout the world

Metric Base Units

One Step Metric Conversions  Convert between a prefix and a base unit  Conversion factors relate prefixes and base units  Example: How many centimeters are equal to 2.5 meters?  Plan: Use conversion (1 cm = 0.01m)  Math: 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:  How many kilometers are equal to meters? (1 km = 1000 m)  How many seconds are equal to microseconds? (1 µs = s)  How many millimoles are equal to 15 moles? (1 mmol = mol)  How many Kelvin are equal to 300 decaKelvin? (1 daK = 10 K)

Two Step Metric Conversions  Convert between 2 prefixes  Conversion factors relate prefixes and base units  Example: How many centimeters are equal to 2.5 kilometers?  Plan: Use conversions (1 cm = 0.01m) and (1 km = 1000 m)  Math: 1. Multiply by everything on top 2. Divide by everything on bottom 3. Diagonal units cancel 2 conversions means 2 “fence posts!” 2.5 km 1000 m 1 cm = cm 1 km 0.01 m

 Sample problems:  How many kilometers are equal to decimeters? (1 dm = 0.1 m) and (1 km = 1000 m)  How many Megaseconds are equal to microseconds? (1 µs = s) and (1 Ms = s)  How many millimoles are equal to 1.5 kilomoles? (1 kmol = 1000 mol) and (1 mmol = mol)  How many centiKelvin are equal to 300 decaKelvin? (1 daK = 10 K) and (1 cK = 0.01 K)

Derived Units  Derived units are not measured directly  They are the result of a calculation involving several measurements  Volume  Density  Units are combinations of the units used in making the measurements  Volume of a regularly-shaped object: m 3, cm 3  Volume of liquid: mL, L  Density of a solid: Density of a liquid: Density of a liquid:

Volume Determination  Volume: The amount of space an object occupies OR the amount of space available inside of an object  Regularly shaped object: V = L x W x H = __cm 3 or __m 3  Irregularly shaped object: Water Displacement  Place object in a known volume of water  Determine the difference in water levels after object is in the water  Convert to appropriate units (1 mL = 1 cm 3 )

Density Determination  Density: the expression for the amount of matter contained in a certain volume  Formula: m DV

Section 3: Communicating with Graphs

A. Types of Graphs  Line Graph  shows the relationship between 2 variables Dependent Variable 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 & Density Mass (g) Volume (cm 3 )