Answer:
The pencil appears to be bent because the velocity of light in water is much lower than in air, but it isn't actually bending. As a result, light rays bend when they hit the boundary layer between air and water, giving rise to the crooked writing utensil. This is referred to as "refraction" by physicists. Because the light can't travel as quickly in the water as it does in the air, the light bends around the pencil, causing it to look bent in the water. Basically, the light refraction gives the pencil a slight magnifying effect, which makes the angle appear bigger than it actually is, causing the pencil to look crooked.
Step-by-step explanation:
In physics, refraction is the change in direction caused by a wave's change in speed as it travels from one medium to another.
Because of the change in speed, the electromagnetic waves that make up light are refracted when they cross the boundary from one transparent medium to another.
When a straight stick is partially immersed in water and viewed at an angle other than 90° to the surface, it appears bent.
A ray of light of one wavelength or color (different wavelengths appear as different colors to the human eye) is refracted, or bent, by an amount that depends on its speed in air and glass, the two speeds depending on the wavelength. A ray of sunlight is made up of many wavelengths that, when combined, appear colorless. The different refractions of the various wavelengths spread them apart as in a rainbow when they enter a glass prism.