80 i need a step by step simple experiment to show that light travels in straight lines until at a point were it enters a new medium.

Materials: laser pointer/ flashlight with a paper with a small slit, glass prism

step 1.) turn on the laser pointer point it up to the ceiling.

step 2.) point to prism, explain how the light refracts in the prism. and how it changes.

(I hope this helps!)

C: plants and animals