Refraction ஒளிவிலகல்
Light bending as it passes from one material into another, like a straw that looks broken in water.
See it in Liquid glass. Drag across the water, then raise Strength to bend the picture more.
In plain words
Light slows down when it passes from air into water or glass. As it slows, it changes direction a little. That bend is refraction. It is why a straw looks broken in a glass and a pool looks shallower than it is. Water tools copy it by shifting each pixel by how steep the wave is at that spot.