1. Independent/Dependent Variables In order to test a hypothesis, scientists design controlled experiments.

2. Experiment In an experiment there are two types of variables Independent Variables Dependent Variables

3. Independent Variables the presence or absence of something manipulated by the person conducting the experiment

4. Dependent Variables the variable being tested that may or may not respond to the independent variable

5. EXAMPLE I hypothesize that more birds will come to my back yard if I install a bird feeder. Independent Variable the presence or absence of the bird feeder Dependent Variable the quantity of birds entering my back yard