Experimental Design Scenarios
For the scenarios below, IDENTIFY THE FOLLOWING where it is appropriate:
A. Ten seeds were planted in each of 5 pots that were found around the house. Each contained
300mg of potting soil. The pots were given the following amounts of water for 40 days: a.)
50mL b.) 100mL c.) 150mL d.) 200mL and e.) 250mL. Pot #3 received the recommended
or amount of water. Plant height was measured at the end of the experiment.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
B. Ms. Southworth’s 10th grade classes decided to perform an experiment to test the durability of zip top bags using
goldfish and oscar fish. They placed five goldfish in five
different brands of zip top bags and placed them into large
aquarium swarming with ten hungry oscars. The same
type of and amount of water was used in each bag and they
were left for five hours.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
C. Justin observed that different kinds and amounts of fossils were present in a cliff behind his house. He wondered why
changes in fossil content occurred from the top to the bottom
of the bank. He marked the bank at five positions:
5, 10, 15, 20, and 25 meters from the surface. He removed one
bucket of soil from each of the positions and determined the
kind and number of fossils at each sample.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
D. Kristen noticed that when she pours Coke into a glass there is always 2-3 inches of fizz at the top. When she is thirsty
she wants it to go down quickly. She thought of ways to reduce the foam once it is in the glass.
She could:
a.) simply wait,
b.) she could blow on it,
c.) put ice in it, or
d.) put her finger in it.
She got four clean glasses and a new 2 liter bottle of Coke. She poured 6 oz of Coke into
each glass, then proceeded to use one method on each glass of Coke. She timed the amount
of time it took for the fizz to go down in seconds by using a stopwatch.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
E. After studying about recycling, members of John’s biology class investigated the effect of various recycled products on
plant growth. John’s lab group compared the effect of different aged grass compost on bean
plants. Because decomposition is necessary for release of nutrients,
the group hypothesized that older grass compost would produce
taller bean plants. Three flats of bean plants (25 plants/flat) were
grown for 5 days. The plants were then fertilized as follows:
a.) Flat A: 450 g of 3 month old compost,
b.) Flat B: 450 g of 6 month old compost, and
c.) Flat C: 0 g compost.
The plants received the same amount of sunlight and water each day. At the end of the 30 days the group recorded
the height of the plants (cm).
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
F. In chemistry class, Allen determined the effectiveness of various metals in releasing hydrogen gas from hydrochloric
acid. Several weeks later, Allen read that a utilities company was burying lead next to iron pipes to prevent rusting.
He hypothesized that less rusting would occur with more active metals.
He placed the following into separate beakers of water:
a.) 1 iron nail,
b.) 1 iron nail wrapped with an aluminum strip,
c.) 1 iron nail wrapped with a magnesium strip,
d.) 1 iron nail wrapped with a lead strip.
He used the same amount of water, equal amounts or masses of the metals, and the same type of iron nails. At the
end of 5 days, he rated the amount of rusting as small, moderate, or large. He also recorded the color of the water.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
G. JoAnna read that certain perfume esters would agitate bees. Because perfume formulas are
secret, she decided to determine if the unknown ester X was present in four different perfumes
by observing the bees’ behavior. She placed a saucer containing 10mL of the first perfume
3m from the hive. She recorded the time required for the bees to
emerge and made observations on their behavior. After 30-minute
recovery periods, she tested the second, third, and fourth perfumes.
All experiments were conducted on the same day when the weather conditions were similar,
e.g. air, temperature and wind.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
H. Jackie read that Aloe vera promoted healing of burned tissue. She decided to investigate the effect of varying amounts
of Aloe vera on the regeneration of planaria. She bisected the planaria to get
10 parts (5 heads and 5 tails) for each experimental group. Jackie applied
concentrations of 0%, 10 %, 20%,
and 30% Aloe vera to the
groups. Fifteen-ml of Aloe
vera solutions were applied.
All of the planaria were
maintained in a growth
chamber with identical food,
temperature, and humidity. On the 15th day, she
observed the regeneration of the planaria parts
and classified their development as full, partial, or none.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
I. Sandy heard that plants compete for space. She decided to test this idea. She bought a
mixture of flower seeds and some potting soil. Into each 5 plastic cups she put the
same amount of soil. In the first cup she planted 2 seeds, in the second cup the planted
4 seeds, in the third cup 8 seeds, and in the fourth cup she planted 16 seeds. In the last
cup she planted 32 seeds. After 25 days, she determined which set of plants looked best.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **
J. Eunice became interested in insulation while her parent’s new house was being built
in a new neighborhood. She decided to determine which insulation would transfer
the least heat. Eunice filled each of 5 jars half-full with water. She
sealed each jar with a plastic lid. Then she wrapped each jar with a
different kind of insulation. She put the jars outside in the direct
sunlight. Later, she measured the temperature of the water in each jar.
Title: **
Hypothesis: **
IV: **
Levels of IV: **
DV: **
# of trials: **
2 constants: **
Control: **
Type of Data: **
2 Improvements: **