1. GRAPHING We use a graph to compare two measurements (variables) in an experiment. The independent variable is the one we control. The dependent variable is the one we want to measure.

2. What do we include on a graph? T A I L S T itle A xis I ncrement L abel S cale

3. TITLE: The graph must have a title that explains what is being compared to what. AXIS: The independent variable (usually the first column of the data table) goes on the X axis. The dependent variable (the second column of the data table) goes on the Y axis. NOTE: Time always goes on the X axis. ALWAYS!!!!!!!!!

4. Increments: The X and Y axis are number lines. You have to decide what numbers to put on each line. Label: You need to identify what the X axis and Y axis stand for. Your label must contain units of measure. It’s not enough to say “distance” and “time.” The labels must say “cm” and “seconds” (it’s ok to abbreviate though).

5. Which number line is the X axis and which one is the Y axis? The X axis is always horizontal, the Y axis is always vertical. Or……. The X stands on his own two feet. The Y reaches for the sky.

6. Scale: The graph should take up about ¾ of the graph paper. Distance (cm) Time (sec) Distance in cm over time Looks kind of silly, don’t you think?

7. For Example: Time (sec)Distance (cm) 522 1026 1531 2034 2540 3044

8. HOW DO WE NUMBER THE Y AXIS? Distance (cm) Time (sec) Distance in cm over time

9. Distance (cm) Time (sec) Y axis X axis 22 26 31 34 40 44 NO NO NO!!!!!!! Distance in cm over time

10. Distance (cm) Time (sec) 50 1.Put your highest value for the Y axis on top. Tip: Sometimes it helps to round this value to the nearest 10. Distance in cm over time

11. Distance (cm) Time (sec) 50 25 2.Now, find ½ of the largest number. Put that value ½ of the way up the Y axis. Distance in cm over time

12. Distance (cm) Time (sec) 50 25 5 10 15 20 30 35 40 45 3.By now, you may be able to fill in the rest of the numbers on the Y axis. Distance in cm over time

13. MAKING THE GRAPH Each data point is an ordered pair. For each, you count to the right for the seconds and you count up for the cm. Let’s do the first one.

14. Distance (cm) Time (sec) 50 25 5 10 15 20 30 35 40 45 (5 sec, 22 cm) Distance in cm over time

15. If you do the same thing with the other points, your graph will look like this:

16. Distance (cm) Time (sec) 50 25 5 10 15 20 30 35 40 45 Distance in cm over time

17. Use a “best fitting line” on your graph. This means, use a ruler to draw a line that is approximately in the middle of all the points. DO NOT CONNECT THE DOTS!!!! EVER!!!!!!

18. Distance (cm) Time (sec) 50 25 5 10 15 20 30 35 40 45 Distance in cm over time