Question

A scientist pours grape juice on three identical white shirts. He then uses three different cleaning products on the shirts and measures how clean they get. What is the independent variable in this experiment?

Answer 1

The independent variable would be the cleaning products. 

The independent variable is the variable that you can manipulate. The change in the independent variable is not affected by other variables. So in this case, the independent variable would be the cleaning product because you will be changing it.