Optical effects refer to visual phenomena that occur when light interacts with different materials or surfaces. These effects can include refraction, where light bends as it passes through substances like glass or water, and reflection, where light bounces off surfaces. Common examples include rainbows, which are created by the refraction and dispersion of light in water droplets, and the shimmering appearance of heat waves on a hot road. Another interesting optical effect is the optical illusion, where the brain interprets visual information in a way that differs from reality. This can occur through patterns, colors, or shapes that trick the eye. Examples include the famous M.C. Escher artworks, which play with perspective and depth, creating images that challenge our perception of space and form.