1. Graphing

2. VARIABLES & DATA TABLES

3. w In an experiment there are 2 types of variables INDEPENDENT VARIABLES & DEPENDANT VARIABLES

4. w a VARIABLE is any factor, or thing that can change during your experiment

5. w a CONTROLED experiment only has 1 variable changing, or being tested w Sometimes a control trial or group is used to compare experimental data to

6. INDEPENDENT VARIABLE w This is the variable we can control in an experiment. w Independent variables are set up ahead of time, before you start following your procedures

7. INDEPENDENT VARIABLE w In a “T” table, or data table, this variable is on the left side. w On a graph, this variable goes on the X axis

8. INDEPENDENT VARIABLE w Examples of common Independent variables: Time-measure every 30 seconds, every day, etc. Distance-measure every 0.5 meters, every 10.0 cm Amount-add 2.0 grams each trial

9. INDEPENDENT VARIABLE w Sometimes the independent variable is called the MANIPULATED variable, because we manipulate or set it to our specifications

10. DEPENDENT VARIABLE w This is the variable we have to observe in an experiment. w Dependent variables are measured during the experiment, after you start following your procedures

11. DEPENDENT VARIABLE w In a “T” table, or data table, this variable is on the right side. w On a graph, this variable goes on the Y axis

12. DEPENDENT VARIABLE w Examples of common Dependent variables: Temperature-record the temperature Mass-find the mass of each object or substance Amount-count the resulting number of items

13. DEPENDENT VARIABLE w Sometimes the dependent variable is called the RESPONDING variable, because it responds to the procedure you are following. We can’t choose what the data will be.

14. GRAPHING NOTES

15. 7 RULES OF GRAPHING w Follow these simple rules for GREAT GRAPHS

16. RULE # 1. Always draw neat lines with a straight edge or ruler and ALWAYS use a pencil!

17. RULE # 2. w Make your graph 3/4 page or 1 full page in size. Small graphs are too difficult to read patterns or results of your experiment.

18. RULE # 3. w Label three places on your graph. 1. TITLE the graph descriptively w WHAT DOES YOUR GRAPH SHOW US? Mention variables?

19. RULE # 3. w 2.Label the x-axis (goes across the bottom of your graph) with the independent variable w 3.Label the y-axis ( the line that goes up & down on the left side of your graph) with the dependent variable w Include units! (in parentheses)

20. Independent Variable Dependent Variable Title

21. RULE # 4. w Number the x and y axis with a regular numerical sequence or pattern. Use values for lines that are easy to work with. exs: 0, 5, 10, 15... 0, 2, 4, 6,.., 0, 0.5, 1.0, 1.5, 2.0 Space out your data so it fills the entire graph. Don’t label every line!

22. RULE # 5. w Points should be small x’s or tiny dots surrounded by small circles

23. RULE # 6. w Get your ruler and place it on the grid. Can you move the ruler so that you can draw a line through all the points? If you can’t, you will have to draw a line of best fit. w If the points look as though they fall approximately on a straight line, draw what is called a “line of best fit” following the ideas set out below. The line of best fit is the line that: passes through as many points as possible and has as many points above the line as below the line.

24. RULE # 7. w If your graph shows more than one trial of data, or has more than 1 line, USE A KEY w A key can be different colored lines, lines with different textures or patterns.

25. The End Good Luck and Happy Data Collecting!