Identifying Variables

Identifying Variables

Learning ObjectivesDifferentiate between the different types of variables.Identify the different types of variables in an experiment.

HousekeepingOn a sheet of paper. Draw the Modified Frayer Model.Remember, all vocabulary words are underlined.

Modified Frayer Model

What is a variable

Variables

3 Kinds of VariablesIndependent Variable something that is changed by the scientist (Input)What is testedWhat is manipulated

3 Kinds of VariablesDependent Variable something that might be affected by the change in the independent variable (Outcome)What is observedWhat is measuredThe data collected during the investigation

3 Kinds of VariablesControlled Variable a variable that is not changedAlso called constantsAllow for a fair test

Example 1:

Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.

Identify the variables in this investigation.

What was the independent variable?Ages of the studentsDifferent ages were tested by the scientist

Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.

What was the dependent variable?The time it to put the puzzle togetherThe time was observed and measured by the scientist

Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.

What was a controlled variable?Same puzzleAll of the participants were tested with the same puzzle.It would not have been a fair test if some had an easy 30 piece puzzle and some had a harder 500 piece puzzle.

Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.

Example 2:

An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.

What are the variables in this investigation?

Independent variable:Sizes of nailsThese were changed by the scientist

An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.

Dependent variable:Number of paper clips picked upThe number of paper clips observed and counted (measured)

An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.

Controlled variables:Battery, wire, type of nailNone of these items were changedAn investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.

Example 3:

The higher the temperature of water, the faster an egg will boil.

Independent variable temperature of waterDependent variable time to cook an eggControlled variable type of eggThe higher the temperature of water, the faster an egg will boil.

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Questions?