Question

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

Explanation:

When light travels from air (a less dense medium) to water (a more dense medium), it slows down. This change in speed causes the light to bend (refraction). Our eyes perceive the refracted light rays, making the part of the pencil underwater appear at a different position relative to the part above water, thus making the pencil look distorted or broken. The first option about light changing temperature is incorrect as temperature change of light isn't relevant here. The second option is wrong because light slows down (doesn't speed up) when entering water from air.

Answer:

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