1. Variables and Graphing

2. What is a Variable?
Something that can be changed.

3. Independent Variable
condition of an experiment that is changed to see how it will affect the dependent variable
What is tested
What is manipulated

4. Dependent Variable
The quantity that responds to the changes in the independent variable
What is observed
What is measured
The data collected during the investigation

5. Constant
The standard in an experiment – which is NOT changed

6. Experimental Groups
Sample that has the independent variable applied to it.

7. Control groups
Sample that is treated like the other experimental groups except that the independent variable is not applied to it
Provides a comparison group

8. Fill in Notes
An independent variable is a variable whose value causes another variables value to change.
A dependent variable is a variable whose value depends on or is determined by another variable.

9. Martha Example
The independent variable is the gas because it causes a change in the price.
The dependent variable is the money because it depends on how much gas is bought.

10. Jake Example
The independent variable is the time because it causes a change in the number of miles.
The dependent variable is the miles because it depends on how long Jake runs.

11. What is a graph? Visual display of info. or data
Different kinds of graphs express different types of information

12. Line graph
Shows a relationship where the d.v. changes due to a change in the i.v.

13. Bar graph
Compares information collected by counting

14. Circle graph/pie chart
Shows the relationship of parts to a whole. (%)

15. Rules for Graphing Identify: x-axis=i.v. (horizontal line)
Y-axis =d.v. (vertical line)
Choose the SCALE
don’t fear the graph paper, fill it up!

16. 3. Pick proper increments
Choose values that are easily divided!
All graphs do not have to begin at zero (0) – how big are the numbers you are using?

17. 4. Label each axis – feet, seconds, etc..
Title the graph! The y-axis vs. x-axis
5. Create a Key! – if you are comparing data, then tell the reader what each line or color stands for