Experimental Design

What is the DEPENDENT variable (effect) in this experiment?

"Does eating breakfast improve test scores?"

• eating breakfast or not

• the grade you got on the test

• what time you get up in the morning

• how tasty the breakfast is

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. Each plant has the same amount of soil, sunlight, and listens to the same music. In this investigation, the independent variable is ...

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

Mr. Pransky wants to see how different surfaces affect how high a tennis ball can bounce. What is the independent variable?

• the different surfaces

• using the same ball

• how high they bounce

• The time of day when they are tested

Tags

NGSS.MS-PS2-2

If you were testing the time it took for objects of different sizes to reach the ground after being dropped from 30 feet in the air, which of these would be the DEPENDENT VARIABLE?

• The time it takes for each object to hit the ground.

• The size of each object.

• The type of object you use.

• The height you drop the object from

A student wants to test the hypothesis of "If salt is added to water then the boiling point of water will decrease (go down)." What is the independent variable?

• Whether salt is added or not

• Boiling Point

• Amount of water

• The time to boil

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS3-4

In any experiment, the independent variable ______________.

• remains the same to not mess up the experiment

• is purposely changed to test the hypothesis

• is known by the scientist before doing the experiment

How many variables can be tested in a controlled experiment?

• one
• two
• three
• as many as possible

Tags

NGSS.MS-PS2-2

Why do we want to test one variable at a time?

• Because it is hard to setup a data table with more
• To know what is causing the changes
• It is what has always been done
• No one really knows

Tags

NGSS.MS-PS2-2

This part of the experiment serves as a basis of comparison; the one variable being tested has been omitted. 

• experimental group
• control group
• data
• variables

A custodian notices some dirty tables and wants to know which cleaner is the best to use. He tests three different cleaners and looks at how well they clean compared to tap water. What is the control group?

• type of cleaner

• tap water

• Surface cleaned

• How well the tables were cleaned