Chapter 1The Nature of Science

Sec. 1: Methods of Science

Science—a method for studying the natural world.

3 Major categories of Science1. Life science—living things2. Earth science—Earth and space3. Physical science—matter and energy

The Scientific Method Scientific Method—an organized

set of investigative procedures.

6 steps of the scientific method1. State the problem—observe an event

in nature and ask “why?”2. Gather information—learn about the

background of the problem3. Form a hypothesis—make a

prediction that explains the observation

More Scientific Method

6 Steps of the scientific method continued

4. Test the hypothesis—conduct experiments to prove (or disprove) the hypothesis

5. Analyze data—record and organize observations

6. Draw conclusions—decide whether the hypothesis was supported (if not, go back)

The Scientific Method

ExperimentingExperiment—tests the effect of one

thing on another using controlled conditions.An experiment needs at least 2 variables.

Variable—a quantity that can have more than one value.Independent variable—the variable you

change in the experiment. Dependent variable—changes because

another variable changes.

Example: identify the variables

You set up an experiment to determine which of 3 fertilizers helps plants grow the most.

In this experiment:What is the independent variable?

type of fertilizerWhat is the dependent variable?

amount of growth

Experimenting (continued)A good experiment should include

constants and a control.

Constant—a factor that does not change when other variables change.

Control—the standard by which test results can be compared.

Example: identify constants and control

Fertilizer ExperimentYou set up 4 trials using the same

soil, water, sunlight, and type of plant. Three of the plants receive a different type of fertilizer. The 4th is not fertilized.

What are the constants? Soil, water, sunlight, & type of plant

What is the control? The 4th, unfertilized plant

Scientific Theories and Laws

Theory—an explanation of things based on many observations and experimentsNOT A GUESSA theory can be disproved by further

experimentation.Scientific law—a statement about

what happens in nature that seems to be true all the time.Example: gravity

Limitations of ScienceScience is a way of explaining the

world.Science cannot explain or solve

everything.Science cannot answer questions

about emotions or values.

Temperature Conversions

Temperatures Fahrenheit Celsius Kelvin

Fahrenheit (F) F˚ (F-32) x 5/9 (F-32) x 5/9+273.15

Celsius (C or o) (C x 9/5) + 32 C˚ C+ 273.15

Kelvin (K) (K-273.15)x 9/5+32 K-273.15 K

Converting to:

Converting from