Data Collecting, Organizing & Analyzing

VARIABLES & DATA TABLES

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

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

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

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

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

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

INDEPENDENT VARIABLE w Your book calls the independent variable the MANIPULATED variable, because we manipulate or set it to our specifications

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

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

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

DEPENDENT VARIABLE w Your book calls the dependent variable the RESPONDING variable, because it responds to the procedure you are following. We can’t chose what the data will be.

Pause for questions???

GRAPHING NOTES

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

RULE # 1. w 1. Always draw neat lines with a straight edge or ruler

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

RULE # 3. w Label the x-axis (goes across the bottom of your graph) w Label the y-axis ( the line that goes up & down on the left side of your graph)

RULE # 4. w Label three places on your graph. w 1. TITLE the graph descriptively w WHAT DOES YOUR GRAPH SHOW US?

RULE # 4. w 2. label the x-axis with the independent variable this is the variable you pre-set before you began collecting data, on the left side of a “T” table common independent variables can be time, or distances

RULE # 4. w 3. label the y-axis with the dependent variable this is the variable you measure when you begin collecting data, on the right side of a “T” table common dependent variables can be mass, or temperature

RULE # 5. w Number the x and y axis with a regular numerical sequence or pattern starting with 0 to space out your data so it fills the entire graph examples: 0, 5, 10, , 2, 4, 6,.., 0, 0.5, 1.0, 1.5, 2.0

RULE # 6. w Number the x and y axis on the lines of the graph, not the spaces between the lines

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.

The End Good Luck and Happy Data Collecting!