Waves serve many functions in our world. Lets consider electromagnetic waves as an example. Electromagnetic waves can provide visible light, carry sound signals in the form of radio waves, and even cook food in the form of microwaves. All these waves consist of many important features that determine their characteristics, function, and allow them to be classified. One such important characteristic that defines function is the distance between two adjacent wave crests. This is referred to as the wavelength. Wavelength can help to determine how much energy a wave has. Consider further the example of visible light. Human's brains interpret visible light based on what wavelength of electromagnetic radiation activates cells located within the eye. The eye is then able to discriminate, based on this wavelength, what color the viewer is observing. If it wasn't for the measure of wavelength, scientists would not have a quantifiable way to sort these different colors.