Refraction is the bending of light as it passes from one medium to another, such as from air into water. This change in speed causes the light to change direction, which is why objects under water appear shifted from their actual position. Refraction is responsible for various optical phenomena, including the formation of rainbows and the focusing of light in lenses. Reflection occurs when light bounces off a surface instead of passing through it. This can happen with smooth surfaces, like mirrors, which create clear images, or rough surfaces, which scatter light and produce a diffuse reflection. Both refraction and reflection are fundamental principles in optics, influencing how we perceive the world around us.