1. Motion and Variables
Exploring Motion

2. Forces Pushes and pulls are forces. Forces make things move.
When something moves we say it is in motion.
A force can be used to change motion and speed.

3. Gravity Gravity is a pulling force between two objects.
Gravity draws objects toward each other.
The bigger the objects, the stronger the gravitational force.

4. Controlled Experiments
Galileo Galilei was among the first modern scientists to perform controlled experiments
In a controlled experiment the scientist must pay close attention to the variables.

5. Variables
There are three kinds of variables in a controlled experiment.
3 Types of Variables:
Independent
Dependent
Controlled

6. Independent Variable
The independent variable is the variable you change.
Example:
The length of string on a pendulum.

7. Dependent Variable
The dependent variable is the what you find out by doing the investigation.
Example:
The number of swings a pendulum makes in 15 seconds.

8. Controlled Variables
The controlled variables are what must stay the same during the investigation.
Example:
The mass of the bob, release position, and length of time a pendulum swings.