Read the following proposed controlled experiments and answer the questions.
Experiment 1: Serious Sandwiches
Dr. Farquart wants to make her home-town a nicer place to live. She has created a new sauce that she predicts
will reduce the production of body gas associated with eating sandwiches from the local cafe. She recruits 100
customers with a history of gas problems. She has 50 of them (group A) eat sandwiches with the new sauce.
The other 50 (group B) eat sandwiches with sauce that looks just like the new sauce but is really only a mixture
of mayonnaise and food coloring. Both groups were told that they were eating the sauce that would reduce gas
production. Two hours after eating the sandwiches, 30 customers in group A reported having fewer gas
problems and 8 customers in group B reported having fewer gas problems.
1. Which group represents the control group?

2. What is the independent variable?

3. What is the dependent variable?

4. What should Dr. Farquart’s conclusion be?

5. Why do you think 8 people in group B reported feeling better?

Experiment 2: Slimotosis
Rafael notices that his 3 pet turtles are suffering from “Slimotosis” which occurs when the shell develops a
nasty slime and gives off a horrible odor. His friend, Ariel, tells him that rubbing seaweed on the shell is the
perfect cure, while Aaron says that drinking kelp water will be a better cure. Rafael decides to test these cures
by rubbing one turtle with seaweed for 1 week and having a second turtle drink kelp water. The third turtle is
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Chemistry A Credit 1 HS-L4L Chemistry A (2017) Page 8
not treated with either cure. After a week of treatment, the slime is gone from the turtle’s shell that drank the
kelp water.
1. What was the initial observation?

2. What is the independent variable?

3. What is the dependent variable?

4. What should Rafael’s conclusion be?