About This Lesson
Light travels in straight lines from a source until it interacts with an object or medium. It can move through transparent materials such as air, water, and glass, and it travels extremely fast—about 300,000 kilometers per second in a vacuum. When light hits an object, it may be reflected, absorbed, or transmitted. It can also change direction through refraction when it passes from one medium to another. Understanding how light travels helps explain everyday phenomena such as shadows, mirrors, lenses, and vision.
