NAME_____________________________________
CLASS_____________________________________
Constants, Variables & Controls
Practice Problems
Name:
Hour:
Date:
INSTRUCTIONS: You will be completing this assignment over the course of two
days:
Day #1: Read each experimental summary. Identify the constants,
independent variables and controls for each experiment and fill in the appropriate
boxes.

CONSTANTS: aspect of an experiment the scientist keeps the SAME;
there is usually a list of many constants in any given experiment

INDEPENDENT VARIABLE: aspect of an experiment the scientist
CHANGES; also called the “manipulated variable”; scientific
experiments should only have ONE independent variable

CONTROL: aspect of an experiment used as a COMPARISON TOOL;
contains all of the constants but not the independent variable; usually
considered the “normal” or “original” that is used to prove change
actually happened during an experiment
Day #2: Read each experimental summary again. Identify the dependent
variable for each experiment and fill in the appropriate box. Then, create a bar
graph for each experiment using the given observations and data.

INDEPENDENT VARIABLE: aspect of an experiment the scientist
CHANGES; also called the “manipulated variable”; scientific
experiments should only have ONE independent variable

DEPENDENT VARIABLE: aspect of an experiment that CHANGES as
a result of the experiment itself; also called the “responding variable”;
this change is usually observed and measured by the scientist at the end
of the experiment; ask yourself what is different at the end of the
experiment that changed since the beginning

GRAPHING: The INDEPENDENT variable is placed on the “X AXIS”
(bottom). The DEPENDENT variable is placed on the “Y AXIS” (side).
Both sides of the graph must be labeled with the correct titles.
NAME_____________________________________
CLASS_____________________________________
Experimental Summary #1:
Observations and Data:
Marissa wanted to find out if ice cubes made with
orange juice would freeze faster than regular ice
cubes. One day after school, she set up an
experiment in her kitchen to test her hypothesis. She
took out two identical ice cube trays and filled one
with 2 cups of orange juice and the other with 2 cups
of plain water. She cleared a spot in the freezer and
put both trays side-by-side on one of the shelves. She
opened the freezer and took the trays out every five
minutes to see if they had frozen yet.
It took the orange juice ice cube tray 195 minutes
to freeze. The regular water ice cube trays froze in
150 minutes.
Scientific Question:
Graph:
Independent Variable:
Controls:
Dependent Variable:
Experimental Summary #2:
Observations and Data:
Farmer Dan was trying to increase the milk
production in his cows. He read that a multiple
vitamin for cows would make them produce more
milk. He wanted to test the claim of the vitamin
company. He used a total of ten of his cows in the
experiment. Five of the cows were given the vitamin
every day for a week, while the other five cows were
not given the vitamin. All ten cows received the
same amount and type of water and food each day.
They were all milked at the same time each day and
lived in the same barn.
The five cows that were given the vitamin were
milked and gave the following amounts of milk for
the week (in Liters): 11, 13, 10, 13, 14. The five
cows that were not given the vitamin were milked
and gave the following amounts of milk for the
week (in Liters): 15, 18, 20, 14, 18.
Scientific Question:
Graph:
Independent Variable:
Controls:
Dependent Variable:
NAME_____________________________________
CLASS_____________________________________
Experimental Summary #3:
Observations and Data:
A worker at the garden shop told Mrs. Greenthumb
that using Miracle Grow fertilizer on her daisies
would make them grow taller. To test this advice,
she took eight of her daisy plants that were all the
same height and transplanted them into eight identical
pots with the same amount and type of soil. They all
receive the same amount of water every other day and
were exposed to equal amounts of sunlight each day.
Four of the plants were given a treatment of fertilizer
once a week, while the other four were not. She
measured the plants once a week for two months to
check for increased growth.
The four daisy plants not given Miracle Grow
fertilizer grew to the following heights (in
centimeters): 30, 24, 28, 24. The four daisy plants
given Miracle Grow fertilizer grew to the
following heights (in centimeters): 23, 31, 29, 23.
Scientific Question:
Graph:
Independent Variable:
Controls:
Dependent Variable:
Experimental Summary #4:
Observations and Data:
Joey was watching his mom cook spaghetti for dinner
and noticed her adding salt to a pot of water she had
on the stove. He asked her why, and she told him
that adding salt to water would make it boil faster.
He didn’t believe her, so they decided to test the idea
by doing an experiment. They put two of the same
type of pots on the stove and filled each with one liter
of water from the sink. They added 2 milligrams of
salt to one of the pots of water. They turned on the
stove burners to high at the same time and observed
the water in the pots until they boiled.
The salt water counted 6 minutes to boil. The
regular water counted 9 minutes to boil.
Scientific Questions :
Graph:
Independent Variable:
Control:
Dependent Variable:
NAME_____________________________________
CLASS_____________________________________
Scientific Method Quiz (7th)
Experimental Summary
You are at Meijer and notice the different types
of soccer balls and want to know which one to
purchase. You decide to test which type of
soccer ball you can kick the farthest. You test a
size 3, size 4 and a size 5 ball. You measure the
distance the ball stays in the air for each of the
trials.
Initial Observation:
Data Chart
Ball
Size
Trial Trial Trial
Ave.
1
2
3
(ft)
(ft)
(ft)
(ft)
3
30
32
35
32.5
4
41
44
48
45
5
28
36
37
34.5
Scientific Question: (correct format)
Hypothesis: (correct format)
Graph:
Independent Variable:
Control Variables: (three) 3 :
Dependent Variable:
What is a Conclusion that we can state about which ball you should by and why?