Name:
Date:
Aim: How can we identify the relationships between variables on a graph?
1. Suzie Q wants to know how different colors of light effect the growth of plants. She believes that plants
can survive the best in white light. She buys 5 ferns of the same species, which are all approximately the
same age and height. She places one in white light, one in blue light, one in green light, one in red light
and one in the closet. All of the ferns are planted in Miracle-Grow and given 20 mL of water once a day
for 2 weeks. After the two weeks, Suzie observes the plants and measurements.
a. What measurements could Suzy make to determine how different colors of light affect the growth of
plants?
b. What is the independent variable?
c. What is the dependent variable?
d. What was the control group in this experiment?
e. List 3 variables that should be held constant in this experiment?
1)
2)
3)
2. The makers of brand A Mouthwash want to prove
that their mouthwash kills more bacteria than the
other 4 leading brands of mouthwash. They
organize 60 test subjects into 6 groups of 10 test
subjects. The data for the experiment is shown to
the right.
a) What is the Independent variable?
b) What is the Dependent variable?
c) What was the control group in this experiment?
d) List 3 variables that should be held constant in this experiment:
1)
2)
3)
3. 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. 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.
Identify the:
a. Independent Variable:
b. Dependent Variable:
c. Control Group:
d. What should Smithers' conclusion be?
e. How could this experiment be improved?
4. 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 check 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.
Identify the:
a. Independent Variable:
b. Dependent Variable:
c. Control Group:
d. What should Homer’s conclusion be?
5. Larry was told that a certain muscle cream was the newest best thing on the market and claims to
double a person’s muscle power when used as part of a muscle-building workout. Interested in this
product, he buys the special muscle cream and recruits Patrick and SpongeBob to help him with an
experiment. Larry develops a special marshmallow weight-lifting program for Patrick and SpongeBob.
He meets with them once every day for a period of 2 weeks and keeps track of their results. Before
each session Patrick’s arms and back are lathered in the muscle cream, while Sponge Bob’s arms
and back are lathered with the regular lotion.
Identify the:
a. Independent Variable:
b. Dependent Variable:
c. Control Group:
d. What should Larry’s conclusion be?