A light beam is a stream of light particles, known as photons, that travel in a straight line. This phenomenon occurs when light is emitted from a source, such as the sun or a light bulb, and can be observed in various forms, including laser beams and sunlight filtering through trees. Light beams can vary in intensity and color, depending on the source and the medium through which they travel. Light beams are essential in many applications, including optical fibers for communication, lasers for cutting and medical procedures, and projectors for displaying images. They also play a crucial role in scientific research, helping to study phenomena in fields like astronomy and physics.