Factor that changes during the experiment is called the?

A variable is the factor that changes in a controlled experiment.

Explanation:

There are usually three variable in an experiment: the constant, the independent variable, and the dependent variable.

Take this experiment for example: Seeing if different amounts of light impact the growth of a plant.

CONSTANT: the plant

INDEPENDENT VARIABLE: the amount of sunlight

DEPENDENT VARIABLE: the growth of the plant (this depends on the sunlight the plant is receiving.)

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.