Section 1: The Methods of Science
 Identify the steps that scientists often
use to solve problems.
 Describe why scientists use variables.
 Compare and contrast science and
technology.
Science studies natural patterns.
 Science is classified into three main
categories:

 life science, Earth science, and physical
science.
 Science explains the natural world;
explanations can change over time.
 Ancient Greek philosophers thought that
everything was composed of five basic
elements:
▪ earth, air, fire, water, and aether
 Scientists investigate nature by
observation, experimentation, or
modeling.

Scientific method: organized set of
investigation procedures
1. State a problem.
2. Gather information
3. Form a hypothesis based on knowledge and
observation.
 Hypothesis: TESTABLE statement that is used
to set up an experiment!
 15 year old males are taller than 15 year old females
 The Steelers are better than the Ravens
 Dinosaurs were blue in color
 Bacteria do not need oxygen to survive
4. An experiment with variables is a common
way to test a hypothesis.
 Experiment: a test of the effect of one
variable on another using controlled
conditions.
 Variable: a quantity that can have more than
a single value.
a) An independent variable is the variable
changed in an experiment to see the effect.
b) A dependent variable is the variable that
changes as a result of the independent
variable.
c) A variable that does not change when other
variables change is a constant.
d) A control is the standard to which test
results can be compared.
5. Analyze data from an experiment or
investigation.
Plant
Amount of Water
Amount of Sun
Height after two
weeks
A
4 oz. every three days
6 hr/day
18cm
B
4 oz. every three days
0 hr/day
6cm
6. Form a conclusion based on the data.
7. Reduce bias by keeping accurate records,
using measurable data, and repeating
the experiment.
 Bias: occurs when what the scientist
expects changes how the results are
viewed.
 Model: represents an
idea, event, or object to
help people better
understand it.
 All models have limitations.
Theory: an explanation based on MANY
observations and investigations
 Scientific law: is a statement about
something in nature that always seems to
be true.

 A theory can never become a law!
Instead theories are used to explain
laws.
 Science deals with the natural world;
questions of value or emotion cannot
be answered.
 Technology: applied science helping
people
Explain why a control is needed in a valid
experiment.
 What is the dependent variable in an
experiment that shows how the volume of
gas changes with changes in temperature?
