Question

Casey wants to determine whether the rate at which melted glass cools affects the strength of the glass. He pours melted glass into a form and cools the glass at different rates. Then, he tests the breaking strength of each form. Which of the following is the test variable in this experiment?

A. type of glass
B. strength of the glass
C. thickness of the glass
D. cooling rate of glass

Help if you know and are sure!

Answer 1

D

"What is a variable?

A variable is used in a Fair Test. A variable is any one of the elements of the test which could be changed. They can change the outcome of an experiment.

In a fair test, only one variable is allowed to be manipulated – all others have to be kept the same,or “controlled”."