Light is believed to have characteristics of waves and particles. In this general introduction to light and color we will consider the wave aspect of light. We experience two main types of waves, longitudinal and transverse, both of which carry energy. Sound waves are an example of longitudinal waves, waves in which the medium waves parallel to the direction of the wave. This can be demonstrated by tugging on a slinky that is being held still at one end.
Light waves are an example of transverse waves.
Unlike sound waves, sound waves, light waves do not need a medium to travel through. Just as it may be helpful to describe a person by their height and body size, waves are also described by their measurements. The amplitude of a wave gives us an indication of the amount of energy being carries by a wave. In a light wave, this would correspond to the intensity of light. Amplitude is measured from the midpoint of a wave to the peak of a trough.