[Maria Gump]

NAME_________________________                                                                            PERIOD___

Worksheet-Identifying the Controls and Variables

I.          Smithers thinks that a special juice will increase the productivity of workers.  He creates two groups of 50 workers each and assigns each group the same task (in this case, they’re supposed to staple a set of papers).  Group A is given the special juice to drink while they work and Group B is not given the special juice.  After an hour, Smithers counts how many stacks of papers each group has made.  Group A made 1,587 stacks, Group B made 2,113 stacks.

1.         What is the control group?

2.         What is the independent variable?

3.         What is the dependent variable?

4.         What should Smithers conclusion be?

II.         Homer notices that his shower is covered in a strange green slime.  His friend Barney tells him that coconut juice will get rid of the green slime.  Homer decides to try this out by spraying half of the shower with coconut juice.  He sprays the other half of the shower with water.  After 3 days of treatment, there is no change in the appearance of the green slime on either side of the shower.           

5.         What is the problem?

6.         What is the hypothesis?

7.         What is the control group?

8.         What conclusion should Homer reach?

III.        Bart believes that mice exposed to a black light will become extra strong.  He decides to perform an experiment by placing 10 mice in front of a black light for 10 seconds.  He compared these 10 mice to another 10 mice that had not been exposed.  His test consisted of a heavy block of wood that blocked the mouse food.  He found that 8 out of 10 of the exposed mice were able to push the block away.  Seven out of the 10 non-exposed mice were able to push the block away.                                                                                                      

9.         What was Bart’s hypothesis?

10.       What was the control group?

11.       What was the independent variable?

12.       What is the dependent variable?

13.       What should Bart’s conclusion be?

IV.       Krusty was told that a certain itching powder was the newest best thing on the market; it even claims to cause 50% longer lasting itches.  Interested in this product, he buys the itching powder and compares it to his usual brand.  One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the experimental itching powder.  Subject A reported having itches for 30 minutes.  Subject B reported to have itches for 45 minutes.

14.       What is the dependent variable?

15.       Explain whether the data supports the advertisements claims about this product.

V.        Lisa is working on a science project.  Her task is to answer the question: “Does Rogooti (which is a commercial hair product) affect the speed of hair growth”?  Her family is willing to volunteer for the experiment.

16.       Describe how Lisa would perform this experiment.  Identify the control group, the independent variable and the dependent variable in your description.