When light hits the boundary between two different materials, it can undergo when light hits the boundary between two different materials, it can undergo both reflection and refraction. refraction. reflection?

When light hits the boundary between two different materials, it can undergo both reflection and refraction.

Reflection is the change in the direction of the wave that strikes the boundary between two materials. It involves a change in the direction of waves when they clash with an obstacle.

Refraction  involves the change in the direction of waves as they move from one medium to  another followed by a change in speed and wavelength (this second medium should have different permitivity for the light to change its initial properties.)

No because a circle or pie graph usually shows percentages you'd need a line graph

The rocks expand when there hot/warm  and contract when they are cold.