Question

what causes the pencil to look broken in this picture?
the light slows down when it enters the water, causing the pencil to look distorted.
the light speeds up when it enters the water, causing the pencil to look straight.
the light changes temperature, causing the pencil to warm up.

Explanation:

When light travels from one medium (air) to another (water), it slows down. This change in speed causes refraction (bending of light). The refraction makes the pencil appear broken.

Answer:

The light slows down when it enters the water, causing the pencil to look distorted.