Name: ______________________________
VARIABLES PRACTICE SHEET
Date: ____________________ Per: _______
COLOR-CODE THESE VARIABLES IN EACH EXPERIMENT:
 MANIPULATED VARIABLE
 RESPONDING VARIABLE
 CONTROLLED VARIABLES
SCENARIO 1 – COMPOST AND BEAN PLANTS
John’s lab group designed an experiment using composted grass to see how it affected the growth
of bean plants (when grass is composted, it decomposes – breaks down – and then it releases
nutrients into the soil where plants can use it).
So, John’s lab group decided to use different ages of composted grass as a fertilizer on bean
plants. The lab group hypothesized that older grass compost would produce taller bean plants.
Three flats of bean plants (25 plants per flat) were grown for 5 days. The plants were fertilized as
follows:
Flat A: 450 g of 3-month-old compost
Flat B: 450 g of 6-month-old compost
Flat C: 0 g of compost
The plants received the same amount of sunlight and water each day. At the end of 30 days the
group recorded the height of the plants (in cm).
SCENARIO 2 – PERFUMES AND BEE’S BEHAVIORS
JoAnna read that Ester X (a scent) in perfumes would agitate bees.
JoAnna decided to determine if Ester X was present in four different perfumes by observing the
behavior of bees. She placed a saucer containing 10 mL of the first perfume 3 meters from the
hive.
She recorded the time required for the bees to come out of their hive and then she made
observations on their behavior. Next, she removed the first saucer and waited 30 minutes to let
the fragrance of the first perfume blow away.
Joanna tested the second, third and fourth perfumes in the same way, waiting for 30 minutes inbetween each saucer. All experiments were conducted on the same day when the weather
conditions were similar (air temperature and wind).
SCENARIO 3 – FOSSILS AND CLIFF DEPTH
Susan observed that different kinds and amounts of fossils were present in a cliff behind her
house. She wondered if there were different types of fossils near the bottom compared to
the top of the cliff.
She marked the bank at five positions: 5,10,15,20, and 25 meters from the surface. She
removed 1 bucket of soil from each of the positions and determined the kind and number
of fossils in each sample.
SCENARIO 4 – COLORS OF FOOD
Gloria wanted to find out if the color of a food would affect whether kindergarten children would select it
for lunch.
She put food coloring into 4 bowls of mashed potatoes. The mashed potatoes were cooked in the same
batch and she put the same amount of potatoes into each identical bowl. The colors were red, green,
yellow, and blue.
Each child chose a scoop of potatoes of the color of their choice. Gloria did this experiment using 100
students. She recorded the number of students that chose each color.
SCENARIO 5 – PLANTS AND SPACE
Sandy heard that plants compete for space. She decided to test whether the number of seeds changed how
plants grew. She bought a mixture of flower seeds and some potting soil.
Into each of 5 plastic cups she put the same amount of soil. In the first cup she planted 2 seeds, in the second
cup she 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 had the most mass per plant.
SCENARIO 6 – SOIL AND WATER
Five planting pots were filled with 500 g each of “Pete’s Potting Soil”. Ten seeds were planted in each pot.
Each pot was given different amounts of distilled water each day for 40 days – the amounts are given below.
Pot1: 50 mL
Pot 4: 200 mL
Pot 2: 100 mL
Pot 5: 250 mL
Pot 3: 150 mL
The height of each plant was measured at the end of the experiment and compared to see which amount of
water grew the tallest plants.
SCENARIO 7 – HOUSE INSULATION
Ellie became interested in insulation for houses while her parent’s new house was being built. She
decided to design an experiment to test which insulation transferred the least heat.
For her experiment, Ellie filled each of 5 jars half-full with water. Then she sealed each jar with a
plastic lid. Next she wrapped each jar with a different kind of insulation (wool blanket, plastic
wrap, newspaper, aluminum foil, and foam sheets)
She put the jars outside in the direct sunlight for 1 hour. Then she measured the temperature of the water in each jar.