Name
Mrs. Jiménez
Date
Period
APS
Good Experiments and Designing Experiments
#1) A research pharmacist needs to determine if a new aspirin on the market called Extra Strength Knockout is
actually more effective than regular strength Knockout in terms of getting rid of headaches. 2 patients are used over
the course of several weeks. The patients are given regular strength Knockout 10 times that they have a headache,
and given Extra Strength Knockout another 10 times they have a headache. Each time, the pharmacist records how
long it takes until the patient reports that the headache has disappeared. He finds out that when the Extra Strength
Knockout was used, the patients averaged a 20% quicker relief rate than the regular strength and so concluded that
the Extra Strength Knockout is indeed more effective than Regular Strength Knockout.
Independent variable?
Dependent variable?
What was the control group? Explain why.
Think of ways that this experiment could be improved to be more trustworthy and explain below.
#2) Bob the Builder wants to build a strong house so that the Big Bad Wolf can’t blow it down. The only material
he can afford is wood. In order to determine which type of wood is the best for this, Bob obtains 20 blocks each of
birch, cherry, maple, and oak woods. He creates identically stacked piles of each type of wood block. He then
places a high powered fan in front of each stack, one stack at a time, and turns it on. Bob records how many blocks
in each pile resist being blown down. He determines that the oak had the most blocks stay in place so he will use
oak to build his house.
Independent variable?
Dependent variable?
Was there a control group? Explain.
In order for us to be sure that this is a “controlled experiment,” what else do we need to know about the procedure?
#3) Jack and Jill are tired of going up the hill to fetch a pail of water. They want to figure out which month is the
rainiest and only fetch the water during that month so as to maximize their effort. So, for 1 year the put out a bucket
at the top of the hill and they collect rainwater and measure how much rain occurs during each month. They analyze
their data and find out that November was the rainiest month. They conclude that November is the best month to go
up the hill from now on.
Independent variable?
Dependent variable?
Is there a control group? Explain.
Decide what you think is the biggest weakness in their experimental design and explain below.
#4) Mrs. Jiménez’s APS students are asked to design an experiment that will determine if heating food coloring will
cause Easter Eggs to dye a darker color. They heat green, blue, red, and orange food coloring to varying
temperatures. They leave the yellow dye at about room temperature (measured to be 30°C), heat the purple dye to
50º C, the red to 70ºC, and blue to 90ºC. They then try dying 20 eggs in each color. The blue eggs look darkly
especially compared to the room temperature yellow ones so they conclude that heating the dye does indeed cause
the Easter Eggs to dye a darker color.
Independent variable?
Dependent variable?
What is the control group? Explain why.
This experiment is NOT controlled. Explain why and how you would fix it so that we might be able to trust the
conclusion.