1. Graphing Data
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2. Graphing Graphs are a useful tool in science.
The visual characteristics of a graph make trends in data easy to see.
One of the most valuable uses for graphs is to "predict" data that is not measured on the graph.

3. Graphing Steps Identify the Variables Determine the range
Determine the scale
Number and label each axis
Plot the points
Draw the graph
Give your graph a title

4. Identify the Variables
Independent Variable - (the thing you changed)
Goes on the X axis (horizontal)
Should be on the left side of a data table.
Dependent Variable - (changes with the independent variable)
Goes on the Y axis (vertical)
Should be on the right side of a data table.

5. Range Subtract the lowest data value from the highest data value.
Do each variable separately.

6. Scale
Determine a scale, (the numerical value for each square), that best fits the range of each variable.
Spread the graph to use MOST of the available space.

7. Label Axis's
You need to tell everyone reading your graph what the graph means.
Be sure to include units.

8. Plotting
Plot each data value on the graph with a dot. You can put the data number by the dot, if it does not clutter your graph.

9. Drawing Draw a curve or a line that best fits the data points.
Most graphs of experimental data are not drawn as "connect-the-dots".

10. Title Your title should clearly tell what the graph is about.
If your graph has more than one set of data, provide a "key" to identify the different lines
While your high school teachers might not like it, I do like putting your name in the title of the graph.
Rachel and Max’s Sunspot Graph

11. Interpolation
Interpolate: predicting data between two measured points on the graph.

12. Extrapolation
Extrapolate: extending the graph, along the same slope, above or below measured data.

13. Operational Definition
A very clear and very precise explanation of the items being measured.
A method to ensure that anyone making the measurement will get the same answer.
Basically you are deciding how each variable is being measured.

14. How will we measure?
In the Bouncing Ball Lab we are measuring how high the ball bounces when dropped.
But where do we measure to?
The bottom. Top, or middle of the ball?
It makes a difference.

15. Our Definition
We will all measure from the floor to the bottom of the ball.
This way we will get consistent results.