Identifying Variables, Control and Experimental Groups

Identifying Variables, Control and Experimental Groups

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Independent Variable

• Controlled by experimenter

• Can be changed or manipulated by the experimenter

• Not affected by dependent variable

How to Identify Independent Variable (Cause)

• Ask questions

• What's different in the experiment?

• What's being tested?

• What's causing the effect?

Multiple Choice

Melissa wanted to know if he could get her flowers to grow, so she planted flowers and watered them daily, then measured the plant height two weeks later. What is causing the change you want to see in the experiment?

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• independent variable

• dependent variable

• constant

• controlled variable

Mario believed that fertilizer will make the plant grow faster, so he treated one plant with fertilizer and the other plant did not receive fertilizer.

Multiple Choice

What is the independent variable?

• Mario

• the plant

• the fertilizer

Dependent Variable

• Responds to independent variable

• Is measured in an experiment or study

How to Identify the Dependent Variable (Effect)

• Ask questions

• What is responding to the cause?

• What is being measured?

Joshua believed that fertilizer will make the plant grow faster, so he treated one plant with fertilizer and the other plant did not receive fertilizer.

Multiple Choice

What is the dependent variable? Hint: What was measured?

• the fertilizer

• plant growth

• Desmontae

Constant

• Does not change

• Stays the SAME

• For example: same height, same amount of water are constants

Multiple Choice

A plant receives the same amount of sunlight and water at the same time each day. What is the constant?

• different amount of sunlight

• different plant

• same amount of sunlight, water and same time

Experimental Group

• Receives treatment or test material

• For example: One plant receives fertilizer

• Fertilizer is the test material, so this plant is the experimental group.

Multiple Choice

Howard believed that fertilizer will make the plant grow faster, so he treated one plant with fertilizer and the other plant did not receive fertilizer. What is the experimental group?

• plant receiving fertilizer

• plant not receiving fertilizer

• plant receiving water because it needs water to grow

Control Group

• Does not receive the treatment or test material

• For example: One plant does not receive fertilizer

• Not receiving the fertilizer makes this plant the control group

Multiple Choice

Angel believed that fertilizer will make the plant grow faster, so he treated one plant with fertilizer and the other plant did not receive fertilizer. What is the control group?

• plant receiving fertilizer

• plant not receiving fertilizer

• Angel believing the plant will grow faster