Final answer:
Refraction is the bending of light waves as they pass from one medium to another, which occurs due to a change in the speed of light. This effect is observable in everyday life, as in the bending of a straw's appearance in water, and is fundamental in optical technologies.
Step-by-step explanation:
The bending of light waves as they move from one medium to another is called refraction. This optical effect is due to the change in speed that light experiences when it crosses the boundary between two different materials. This change in speed results in a change in direction, or bending, of the light wave. For instance, if you've ever looked at a straw in a glass of water, it appears to be bent or broken at the water's surface due to refraction. This concept is essential in understanding how lenses work and how they are able to focus light to form images. Refraction is an important principle in fields ranging from astronomy to optometry, as it affects how we perceive light and color.