1. Sample Experiments

2. Three redwood trees kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. Height of the tree is measured once a week.
What is the control group?
What is the experimental group?
What is the independent variable?
What is the dependent variable?

3. Spontaneous Generation
Francisco Redi put meat into 2 jars. One jar was left open, one had a screen over the top. He left them to sit on the counter top. The jar with no lid had maggots growing on the meat, the jar with the screen did not.
What is the control group?
What is the experimental group?
What is the independent variable?
What is the dependent variable?
Life comes from NONLIVING things

4. Spontaneous Generation
Louis Pasteur had a flask of broth that he boiled and left sitting for a year. Nothing happened to the broth. After a year he broke the neck of the flask and left it to sit on the countertop. After one week bacteria started to grow in the broth. What is the control group? What is the experimental group? What is the independent variable? What is the dependent variable?

5. Pea plants are given different amounts of water over a 3 week period
Pea plants are given different amounts of water over a 3 week period. 1st plants gets 400 ml of water, 2nd receives 200 ml of water, 3rd receives 100 ml of water and the 4th receives no extra water, only what it gets naturally. The height of the plants are recorded daily.
What is the control group?
What is the experimental group?
What is the independent variable?
What is the dependent variable?

6. One tank of goldfish is fed the normal amount (once daily)
One tank of goldfish is fed the normal amount (once daily). A 2nd tank is fed twice daily and a 3rd is fed 4 times daily during a 6 week study. The fish’s body fat is recorded daily.
What is the control group?
What is the experimental group?
What is the independent variable?
What is the dependent variable?

7. You are determining if increased ultraviolet radiation from the decrease in the ozone layer is killing off frog tadpoles. Group 1 is in a five gallon glass aquarium (glass filters out UV radiation). Group 2 is covered with an acrylic plexiglass, (does not filter out the U.V. radiation. You then place the groups outside for a period of a month.
Results Group Group 2
Number of tadpoles
started with
Number finished
What is the independent and dependant variable?
Which is the control group, and which is the experimental group?