Parts of an Experiment

The one factor that a scientist changes during an experiment.

• Controlled Variable

• Dependent Variable

• Independent Variable

The variable that is measured.

• Controlled Variable

• Dependent Variable

• Independent Variable

In a controlled experiment, how many independent variables can be tested at a time?

• one

• none

• two or more

• how ever many makes sense.

Why is it important to have only one independent variable and to control the other variables when performing science experiments?

• So you can tell which factor is causing the change in the experiment.

• It does not matter, you can have as many independent variables as you want.

Ben makes five paper helicopters with different wing lengths. He drops them the same way from a height of two meters for five trials each. He records the amount of time it takes for each helicopter to fall to the ground.

What is the independent variable?

• Dropping the same way

• Wing Length

• Amount of time it takes the helicopter to hit the floor

• Dropping from the same height

Ben makes five paper helicopters with different wing lengths. He drops them the same way from a height of two meters for five trials each. He records the amount of time it takes for each helicopter to fall to the ground.

What is the dependent variable?

• Dropping the same way

• Wing Length

• Amount of time it takes the helicopter to hit the floor

• Dropping from the same height

Ben makes five paper helicopters with different wing lengths. He drops them the same way from a height of two meters for five trials each. He records the amount of time it takes for each helicopter to fall to the ground.

What are two controlled variables? (Select 2 answers)

• Dropping the same way

• Wing Length

• Amount of time it takes the helicopter to hit the floor

• Dropping from the same height

An experiment is performed on plants to see how different liquids affect plant growth. Each plant in the experiment is given a different liquid; water, apple juice, or milk.  In this investigation, the independent variable is ...

• The type of plant
• The amount of sunlight
• The type of music
• The type of liquid

Mrs. Ahlers set up an experiment to see how the mass of a ball affects the distance it rolls off a ramp. What is the dependent variable?

• Distance traveled by the ball
• Height of the ramp
• Mass of the ball
• Where the experiment took place.

Cindy wanted to find out how the amount of sunlight affects the growth of plants. She placed two tomato plants in 10 inch pots with potting soil and watered them ¼ cup each day. One plant was placed under a cardboard box and one was placed in the sunlight. She measured the growth of the plant each week for three weeks.

What are two controlled variables? (Select 2)

• Using the same type of plant

• Each plant was placed in a 10 inch pot

• The growth of the plant

• One plant is in the sunlight and the other is under a box

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