Why the person leg's appear to be short when standing in a tank?

When a person stands in a tank filled with water, the refraction of light at the water's surface can create an optical illusion that makes their legs appear shorter. This occurs because light bends as it passes from water to air, causing the submerged parts of the body to look distorted and shorter than they actually are. Additionally, the contrast between the water and air can further enhance this visual effect, leading to the perception of shorter legs.