Variables in a Scientific Experiment

Controlled Experiment

• Controlled Experiments have variables.• Variables are the things in an

experiment that are or could be changed.• There are three kinds of variables.

Independent Variable

• Also called Manipulated Variables.• This is changed by the scientist on purpose.• It is a single factor in an experiment that the

scientist chooses to change.• It is the difference between groups.• The “cause” of a change.• When something is observed or changed over a

period of time, then TIME is the independent variable.

Independent Variable Trick to Remember

IChOPIndependentChangeOnPurpose

Dependent Variable

• Also called Responding Variable.• This responds to the Independent Variable

changing.• It is the effect caused by the Independent

Variable.• What is observed.• What is measured.• The data collected.

Dependent Variable Trick to Remember

DRUMDependentResponseUMeasure

Constant Variables

• Things in an experiment that are kept the same.• They could change, but don’t.• Kept constant by the scientist.• Allow for a fair test.

Number 1

Changing your underwear every day may help you to feel more refreshed.

Number 2

Getting more dates would be likely if you start wearing deodorant.

Number 3

Brushing your teeth can reduce the chances of having bad breath.

Number 4

Having lots more friends can happen if you bring your sweaty gym clothes home for your mom to wash.

Number 5

Wearing a Speedo whileswimming may take seconds off your breaststroke.

Number 6

To make your family happy, wear odor-eaters in your shoes.

Number 7

Passing gas on your 1st date will guarantee the loss of a second date.

Number 8

Flossing your teeth with your toenail will make your sister vomit.

Copy this template into page ____ of your journals.

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