Name: _______________________________________________________ Period: __________

Analyzing Scientific Experiments


In the experiment illustrated below, a botanist wanted to determine the effects of different colored light on plant growth. To do this, he set up two experiments. He grew one plant under blue light and one under red light and gave each plant the amount of water shown.

Study the illustrations and answer the questions that follow:

1.      At the end of the experiment, Plant 1 had grown 10 cm and Plant 2 had grown 5 cm. The botanist concluded that plants grow better under red light. Comment on this conclusion.




2.      How would you revise the experiment to make it scientifically valid? Use the spaces below to show the values of the variables in your redesigned experiment.

                                             Plant 1                                  Plant 2                                Plant 3


Light                     ____________________   ____________________  _________________

Temperature        ____________________   ____________________  _________________

Water                    ____________________   ____________________  _________________

Time                      ____________________   ____________________  _________________

Plant                      ____________________   ____________________  _________________

3.      What is the control group in this experiment? ___________________________________


4.      What are the experimental groups in this experiment? ____________________________



5.      What is the manipulated variable in this experiment? _____________________________


6.      What is the responding variable in this experiment? ______________________________



7.      What are the constants in this experiment? _____________________________________