Why does something appears to be enlarged in water?

Objects appear enlarged in water due to refraction, which is the bending of light as it passes from one medium to another with a different density. When light travels from air into water, it slows down and changes direction, making the object appear closer and larger than it actually is. This optical illusion occurs because our brains interpret the light rays as coming from a straight line, leading to a distorted perception of the object's size and position.