Transcript Controlled Experiment Quiz

A Biology student wants to know if putting aspirin in the soil
will make a rose plant grow more quickly. She buys two rose
plants and places 1 tablet of aspirin in the soil of each plant.
Plant A
Plant B
Each day, she gives the plants the same amount of fresh
water (0.5 liter). The plants receive the same amount of
sunlight each day (12 hours).
0.5 liter
0.5 liter
12 hours
12 hours
1 tablet
Plant A
Plant B
1 tablet
1. Identify this experiment as controlled or uncontrolled,
and explain your answer. Use the term “M.V.” in your
answer.
At the advice of her Biology teacher, the student re-designs
the experiment. She puts aspirin in the soil of plant A only.
She gives both plants the same amount of sunlight each day
(12 hours). Plant B receives 0.5 liter of water daily, while
plant A receives 1 liter of water daily to help dissolve the
aspirin.
0.5 liter
1 liter
12 hours
12 hours
1 tablet
Plant A
Plant B
2. Identify this experiment as controlled or uncontrolled,
and explain your answer. Use the term “M.V.”
12 hours
12 hours
1 liter
0.5 liter
1 tablet
Plant A
Plant B
3. In the re-designed experiment, plant A grew TWICE as fast
as plant B. Based on the data, the student concludes that
her hypothesis was supported; aspirin does seem to help
roses grow faster. Explain to the student why she is getting
false results. Use the term M.V. in your answer.
Plant A
Plant B
4. Re-design the student’s experiment to make it controlled.
(2-3 sentences; brief description of how you would do it).
Plant A
Plant B
5. What is the RV in your experiment? Explain why it is the
RV.
Plant A
Plant B
6. What is the MV in your experiment? Explain why it is the
MV.
Plant A
Plant B
7. List three variables that must be controlled in this
experiment.
In the L-Dopa experiment, Dr. Sayer first administers 200 mg
of the drug in orange juice; he then administers 1500 mg of
the drug in milk.
8. Identify Dr. Sayer’s experiment as controlled or
uncontrolled, and explain why.