Experimental Design (Controlled Experiment)

What do you think this investigator is testing?

• How different amounts of sunlight will impact the growth of each plant

• How different amounts of water will impact the growth of each plant. 

• How different species of plant react to different amounts of water. 

What is the independent variable in this experiment?  

• the amount of water the plants receive

• the amount of soil the plants were planted in

• the type of plant that was planted in each pot

What do we call the variables that are kept the same, or controlled, during an experiment? 

• independent variables

• dependent variables

• constant variables 

  *can also be called controlled variables*

What is the dependent variable in this experiment? 

• the growth of the plants

• the amount of water the plants received

• the amount of time the plants grew

How many independent variables can there be an a controlled experiment? 

• many

• 1

• 2

How many dependent variables can there be in a controlled experiment? 

• many

• 1

• 2

How many constants (controlled variables) can there be in a controlled experiment

• many

• 1

• 2