Teacher Page
Control vs. Constant:
A Strategy to Understand their Differences
Pre—
students use a highlighter to highlight what they
think are relevant definitions of the two terms
Mid—
students check their definitions, correct them if
necessary and then draw pictures that will help
them remember the words “control” and
“constant”; a suggestion is to have them draw pics
of labs they have done already that have constants
and controls
Post--
students will practice identifying the controls and
constants in several examples
Student Page
Control vs. Constant
Often students confuse, misunderstand or interchange two important elements of the scientific method:
controls and constants. It is easy to see two words that both start with the same “con” and both are used
in the scientific method. In order to recognize the differences, please complete the following.
Read the two definitions below and highlight any/all parts of the definitions that are relevant
(important) to science.
Dictionary.com Unabridged (v 1.1) –
con·trol kənˈtroʊl - Show Spelled
Pronunciation[kuh n-trohl] Pronunciation Key Show IPA Pronunciation verb, -trolled, -trol·ling,
noun
–verb (used with object)
1. to exercise restraint or direction over;
dominate; command.
2. to hold in check; curb: to control a horse; to
control one's emotions.
3. to test or verify (a scientific experiment) by a
parallel experiment or other standard of
comparison.
4. to eliminate or prevent the flourishing or
spread of: to control a forest fire.
5. Obsolete. to check or regulate (transactions),
originally by means of a duplicate register.
–noun
6. the act or power of controlling; regulation;
domination or command: Who's in control
here?
7. the situation of being under the regulation,
domination, or command of another: The car
is out of control.
8. check or restraint: Her anger is under
control.
9. a legal or official means of regulation or
restraint: to institute wage and price controls.
control.
16. Philately. any device printed on a postage or
revenue stamp to authenticate it as a
government issue or to identify it for
bookkeeping purposes.
17. a spiritual agency believed to assist a
medium at a séance.
18. the supervisor to whom an espionage agent
reports when in the field.
Dictionary.com Unabridged (v 1.1)
con·stant ˈkɒn stənt - Show Spelled Pronunciation[konstuh nt] Pronunciation Key - Show IPA Pronunciation
–adjective
1. not changing or varying; uniform; regular;
invariable: All conditions during the three
experiments were constant.
2. continuing without pause or letup; unceasing:
constant noise.
3. regularly recurrent; continual; persistent: He
found it impossible to work with constant
interruption.
4. faithful; unswerving in love, devotion, etc.: a
constant lover.
5. steadfast; firm in mind or purpose; resolute.
6. Obsolete. certain; confident.
–noun
10. a standard of comparison in scientific
experimentation.
7. something that does not or cannot change or
vary.
11. a person who acts as a check; controller.
8. Physics. a number expressing a property,
quantity, or relation that remains unchanged
under specified conditions.
9. Mathematics. a quantity assumed to be
unchanged throughout a given discussion.
12. a device for regulating and guiding a
machine, as a motor or airplane.
13. controls, a coordinated arrangement of such
devices.
14. prevention of the flourishing or spread of
something undesirable: rodent control.
15. Baseball. the ability of a pitcher to throw
the ball into the strike zone consistently:
The rookie pitcher has great power but no
—Synonyms 1. unchanging, immutable, permanent. 2.
perpetual, unremitting, uninterrupted. 3. incessant,
ceaseless. 4. loyal, staunch, true. See FAITHFUL. 5. steady,
unwavering, unswerving.
—Antonyms 1. changeable. 2. fitful. 3. sporadic. 4.
unreliable
Student Page
Now read the following two definitions. Do your highlighted choices seem to fit? If no, please go
back up and correct them.
The American Heritage Science Dictionary
control (kən-trōl') Pronunciation Key
A standard of comparison for checking or verifying the results of an experiment. In an experiment to test the
effectiveness of a new drug, for example, one group of subjects (the control group) receives an inactive substance
or placebo , while a comparison group receives the drug being tested
The American Heritage Science Dictionary
constant
(kŏn'stənt)
A quantity that is unknown but assumed to have a fixed value in a specified mathematical context. A theoretical or
experimental quantity, condition, or factor that does not vary in specified circumstances. Avogadro's number and
Planck's constant are examples of constants.
Next you are going to make a picture that will remind you of the word and its definition…
CONSTANT
CONTROL
Student Page
Finally, read the following and answer the questions.
Example:
An electromagnet will pick up more nails if more batteries are put in the circuit.
The number of batteries can be changed to determine its effect on the electromagnet.
Independent Variable-number of batteries in a circuit
Dependent Variable-number of nails the electromagnet picks up
Constants-type of battery, size and amount of wire, type of connection, type of circuit, size and type of
paper clips, procedure for picking up the clips
Control—number of nails picked up with 1 battery
Now, it’s your turn.
1. Apple trees that receive the most water will produce the largest apples.
The amount of water can be changed to determine its effect on the size of the apples grown.
a. Independent Variableb. Dependent Variablec. Constants-
2. Students will score better on spelling tests by increasing the number of minutes each student studies.
The amount of time can be changed to determine its effect on the spelling scores.
a. Independent Variableb. Dependent Variablec. Constants-age of student, gender of student, time of test, test giver, study method
d. Control—
3. What is the effect of the amount of salt on the height an egg floats?
a. Constantsb. Control—
4. What is the effect different liquids have on an object floating in liquid? The liquids used are corn oil, milk, soda
pop, water, orange juice, and tomato juice.
a. Constantsb.
Control—