Identifying Variables - Notes

Identifying Variables

​Independent, dependent & control

Independent Variables

An independent variable is the
factor in an experiment that the
scientist is purposely changing so that they can learn something.

Example:

Brad wants to know if some colors of cars fade faster than other colors.

Example:

Brad wants to know if some colors of cars fade faster than other colors.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

Multiple Choice

What is the INDEPENDENT variable?

(factor changed ON PURPOSE)

• Car Type

• Car Color

• Car Age

• Time in Sun

Example:

Brad wants to know if some colors of cars fade faster than other colors.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

​Independent Variable = Color of Car

Example:

Brad wants to know if crickets chirp at different speeds at different temperatures.

Example:

Brad wants to know if crickets chirp at different speeds at different temperatures.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

Multiple Choice

What is the INDEPENDENT variable?

(factor changed on purpose)

• Type of Cricket

• Temperature

• Speed of Chirps

• Type of Animal

Example:

Brad wants to know if crickets chirp at different speeds at different temperatures.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

​Independent Variable = Temperature

Example:

Brad wants to know if crickets chirp at different speeds at different temperatures.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

​Independent Variable =

Example:

Brad wants to know if different acids produce different amount of gas when combined with baking soda.

Example:

Brad wants to know if different acids produce different amount of gas when combined with baking soda.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

Multiple Choice

What is the INDEPENDENT variable?

• Amount of gas

• Amount of Baking Soda

• Amount of Acid

• Type of Acid

Example:

Brad wants to know if different acids produce different amount of gas when combined with baking soda.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

​Independent Variable = Type of Acid

Example:

Brad wants to know if different colored lights will make a difference in how wide a person's pupil will open.

Example:

Brad wants to know if different colored lights will make a difference in how wide a person's pupil will open.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

Multiple Choice

What is the INDEPENDENT variable?

• Pupil Width

• Color of Light

• Color of Eye

• Time Light is On

Example:

Brad wants to know if different colored lights will make a difference in how wide a person's pupil will open.

What Brad changes on purpose is the INDEPENDENT VARIABLE.

​Independent Variable = Color of Light

Dependent Variables

The dependent variable is the factor in an
experiment that the scientist is measuring so that they can see if their hypothesis was correct or not.

Every time the scientist runs a trial, they will need to record their observations. What they are recording on their Data table is the Dependent variable.

The dependent variable is the factor in an
experiment that the scientist is measuring so that they can see if their hypothesis was correct or not.

Example:

Brad wants to know if some colors of cars fade faster than other colors.

Example:

Brad wants to know if some colors of cars fade faster than other colors.

What Brad measures & records on the data table is the DEPENDENT VARIABLE.

Multiple Choice

What is the DEPENDENT variable?

• Amount of Fading

• Type of Car

• Which color is used

• Age of Car

Example:

Brad wants to know if some colors of cars fade faster than other colors.

What Brad measures & records on the data table is the DEPENDENT VARIABLE.

​Dependent Variable = Amount of Fading

Example:

Brad wants to know if crickets chirp at different speeds at different temperatures.

Example:

Brad wants to know if crickets chirp at different speeds at different temperatures.

What Brad measures & records on the data table is the DEPENDENT VARIABLE.

Multiple Choice

What is the DEPENDENT variable?

• Temperature

• Chirping Speed

• Change in Temperature

• Amount of time in Temperature

Example:

Brad wants to know if crickets chirp at different speeds at different temperatures.

What Brad measures & records on the data table is the DEPENDENT VARIABLE.

​Dependent Variable = Chirp Speed

Example:

Brad wants to know if different acids produce different amounts of gas when combined with baking soda.

Example:

Brad wants to know if different acids produce different amounts of gas when combined with baking soda.

What Brad measures & records on the data table is the DEPENDENT VARIABLE.

Multiple Choice

What is the DEPENDENT variable?

• Amount of Gas

• Amount of Baking Soda

• Type of acid

• Amount of acid

Example:

Brad wants to know if different acids produce different amounts of gas when combined with baking soda.

What Brad measures & records on the data table is the DEPENDENT VARIABLE.

​Dependent Variable = Amount of Gas

Example:

Brad wants to know if different colored lights will make a difference in how wide a person's pupil will open

Example:

Brad wants to know if different colored lights will make a difference in how wide a person's pupil will open

What Brad measures & records on the data table is the DEPENDENT VARIABLE.

Multiple Choice

What is the DEPENDENT Variable?

• Width of Pupil

• Color of Eye

• Color of Light

• Time light is shining

Example:

Brad wants to know if different colored lights will make a difference in how wide a person's pupil will open

What Brad measures & records on the data table is the DEPENDENT VARIABLE.

​Dependent Variable = Width of Pupil

Control Variables

A control variable is a factor in an experiment that should remain constant
or the same for the entire experiment.

A control variable is a factor in an experiment that should remain constant
or the same for the entire experiment.

If the factor did change, it could negatively affect the outcome of the experiment.

Example:

Brad want to know if some colors of cars fade faster than other colors.

Example:

Brad want to know if some colors of cars fade faster than other colors.

For the experiment, he is going to purposefully change the colors of the car.

Example:

Brad wants to know if some colors of cars fade faster than other colors.

For the experiment, he is going to purposefully change the colors of the car.


He should NOT change anything else.

Example:

Brad want to know if some colors of cars fade faster than other colors.

For the experiment, he is going to purposefully change the colors of the car.


He should NOT change anything else.


What variables should he keep the SAME?

Open Ended

List TWO control variables

Example:

Brad want to know if some colors of cars fade faster than other colors.

For the experiment, he is going to purposefully change the colors of the car.


He should NOT change anything else.


What variables should he keep the SAME?

age of car time of year car model
time in sun brand of paint age of paint

Example:

Brad want to know if crickets will chirp at different speeds at different temperatures.

Example:

Brad want to know if crickets will chirp at different speeds at different temperatures.

For the experiment, he is going to purposefully change the temperature of the cage.


He should NOT change anything else.

Example:

Brad want to know if crickets will chirp at different speeds at different temperatures.

For the experiment, he is going to purposefully change the temperature of the cage.


He should NOT change anything else.


What variables should he keep the SAME?

Open Ended

List TWO control variables

Example:

Brad want to know if crickets will chirp at different speeds at different temperatures.

For the experiment, he is going to purposefully change the temperature of the cage


He should NOT change anything else.


What variables should he keep the SAME?

size cage time of day time in temperature
sex of cricket cricket age type of cricket

Example:

Brad wants to know if different acids produce different amounts of gas when combined with baking soda.

Example:

Brad wants to know if different acids produce different amounts of gas when combined with baking soda.

For the experiment, he is going to purposefully change the type of acid used.


He should NOT change anything else.

Example:

Brad wants to know if different acids produce different amounts of gas when combined with baking soda.

For the experiment, he is going to purposefully change the type of acid used.


He should NOT change anything else.


What variables should he keep the SAME?

Open Ended

List TWO control variables

Example:

Brad wants to know if different acids produce different amounts of gas when combined with baking soda.

For the experiment, he is going to purposefully change the type of acid used.


He should NOT change anything else.


What variables should he keep the SAME?

amount of acid amount of baking soda
container size time combined

Example:

Brad wants to know if different light colors will make a difference in how wide a person's pupils will open.

Example:

Brad wants to know if different light colors will make a difference in how wide a person's pupils will open.

For the experiment, he is going to purposefully change the color of the light.


He should NOT change anything else.

Example:

Brad wants to know if different light colors will make a difference in how wide a person's pupils will open.

For the experiment, he is going to purposefully change the color of the light.


He should NOT change anything else.


What variables should he keep the SAME?

Open Ended

List TWO control variables

Example:

Brad wants to know if different light colors will make a difference in how wide a person's pupils will open.

For the experiment, he is going to purposefully change the color of the light.


He should NOT change anything else.


What variables should he keep the SAME?

light brightness wait time before light
time in light eye (left/right)
person light brand and age