Control vs



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

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.

Unabridged (v 1.1) –

con·trol /kənˈtroʊl/ Pronunciation Key - Show Spelled Pronunciation[kuh[pic]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. |

|10. |a standard of comparison in scientific experimentation.|

|11. |a person who acts as a check; controller. |

|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 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. |

Unabridged (v 1.1)

con·stant [pic]  /ˈkɒn[pic]stənt/ Pronunciation Key - Show Spelled Pronunciation[kon-stuh[pic]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

|7. |something that does not or cannot change or vary. |

|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. |

—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

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 [pic][pic][pic]  (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

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 Variable-

b. Dependent Variable-

c. 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 Variable-

b. Dependent Variable-

c. 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. Constants-

b. 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. Constants-

b. Control—

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