Fertilizer

Reviewing Controls & Control Groups

Controls or Controlled Variables (Constants)

Stays the SAME in an experiment

For example: same soil, same amount of water, same amount of light are constants when given to all test subjects

Multiple Choice

A group of plants receives the same amounts of sunlight BUT different amount of water at the different times each day. What is the constant or controls?

• water

• amount of sunlight

• times of the day

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

Jim loves tomatoes & beans. He believed that fertilizer will make the plants grow faster, so he treated one plant with fertilizer and the other plant did not receive fertilizer. They both received the same amounts of water & sunlight. Which one is the experimental group?

• plant receiving fertilizer

• plant not receiving fertilizer

• tomatoes

• both plants

Control Group

Does not receive the treatment or test material For example: One plant does not receive fertilizer & the other does. Not receiving the fertilizer makes this plant the control group because it gets no treatment or it not manipulated.

Multiple Choice

Michael loves lettuce & lima beans. He believes that fertilizer will make the plant grow faster, so he treated one plant with fertilizer and the other plant did not receive fertilizer. They both received the same amounts of water & sunlight? What is the control group?

• plant receiving fertilizer

• plant not receiving fertilizer

• lima beans

• both plants

Multiple Choice

Michael loves lettuce & lima beans. He believes that fertilizer will make the plant grow faster, so he treated one plant with fertilizer and the other plant did not receive fertilizer. They both received the same amounts of water & sunlight? What is the controls or controlled variables?

• fertilizer

• water & sunlight

• water only

• lima beans

Open Ended

Explain what controls/controlled variables are in your own words.

Answer

Factors that remain “constant” 

throughout an experiment

All test groups have same conditions 

except for independent variable

Ex. same amount of water, soil type, pots

sunlight, etc. Except the independent variable.

Open Ended

Explain the difference between control group & experimental group in your own words.

Answer

Control Group: Test group that does not receive the independent variable or treatment It is the normal result you are 

comparing your other test results to.

Experimental Group: Receives treatment or Independent Variable