Refraction of light (4th Grade)

Experiments to understand refraction, by 4th Grade:

1. Put a pencil into a transparent glass full of water. Observe how it seems to be bent:

2. First, draw an arrow on a paper and stick in on the wall. Then, fill a glass with some water and put it right in front of the paper. Observe how the arrow changes direction!!!

So, what does REFRACTION consist of?

Light bends and changes direction when it passes from one transparent medium to another (water, glass,...).