Question

Lidia plans an experimental investigation to see how the thickness of a lens affects the point where a beam of light is focused. She plans to shine light through a lens and measure the distance to a screen that is placed where the beam focuses.

What are the controls in Lidia’s investigation?

Answer 1

since she is using thickness of the lens as the independent variable and the point of light distance as the dependent variable, then other variables, like the type/color of light, the device used to create the light, the type of screen, the location of the screen, etc.