Nature of light
For a long time scientists were not sure about how light travels through space. Some thought that light behaves like a wave, others claimed that light particles travel in a straight line. Today, scientists agree that light is an electromagnetic wave made up of electrical and magnetic forces that travel through space at a very high speed. However, light is also a stream of particles called photons, which travel like a beam.
Light waves can be compared to waves in water. They have a wavelength, frequency and amplitude. The wavelength is the distance between the two highest parts of a wave, the frequency is the number of times that a wave passes a certain point every second, and the amplitude is the distance between the highest and lowest points of a wave.