Final answer:
When standing in water, your legs appear shorter due to refraction. The bending of light as it passes from water to air creates an apparent position that is higher than the actual position, making the legs appear shorter.
Step-by-step explanation:
When standing in water, your legs appear shorter due to the phenomenon of refraction. Refraction is the bending of light as it passes from one medium to another, in this case from water to air. This bending of light causes the apparent position of the legs to be higher than their actual position, making them appear shorter.
To understand this, we can use a ray diagram. The rays of light coming from the feet of the person in the water bend away from the normal (the perpendicular line to the surface of the water) as they pass into the air, creating an apparent position of the legs that is higher. The higher apparent position results in the legs appearing shorter when viewed by an observer outside of the water.