VariablesMs. Underberger

September 2, 2015

• A variable is what you are trying to measure. There are 4 types of variables.

1. Independent Variable

• Causes changes in other variables• The experimenter often chooses the

independent variable

2. Dependent Variable

• Is changed by the independent variable• The “effect” of the variables impacting it• Experimenter cannot control the dependent

variable

3. Control Variable

• Does not receive the independent variable• What is considered “normal”

4. Constant Variables

• What is the same for all variables and parts of the experiment

• Usually relates to materials

Example with FREDQuestion: How can we put the lifejacket back on FRED without knocking him off of the cup and using only paperclips? Hypothesis: I predict if we open the paperclips and loop them under the cup, then we can lift the cup and get the lifesaver to stretch and put on FRED. Independent Variable: Bending of the paperclips Dependent Variable: Lifting up cup & getting lifesaver on FRED Control Variable: Keeping paperclips as are and not opening or bending themConstant Variable: set-up of experiment, materials, rules

Example: FertilizerQuestion: How can I make my flowers grow taller? Hypothesis: If I put fertilizer in the soil, then the flowers with fertilizer will grow taller in 1 week than flowers without fertilizerIndependent Variable: fertilizerDependent Variable: how tall the flower growsControl Variable: plant without fertilizerConstant Variables: 1 week time frame, pot size, type of soil, type of flower, watering plant daily recording height daily