Electromagnetic Spectrum

Many people think that light only exist in the forms that are visible to us. This is not true. The visible light that people see only accounts for a small fraction of all wavelengths of light. The entire range of light, or electromagnetic radiation, is know as the electromagnetic spectrum shown in the picture below. 

The region on this spectrum with the highest energy (so the shortest wavelengths) are gamma rays and the region with the lowest energy (so the longest wavelengths) are radio waves. The visible region of the spectrum has wavelengths from about 400-700 nm. The measure of wavelength determines the color on the visible spectrum. As you can see in the picture above, a wavelength of 400 nm represents violet and a wavelength of 700 nm represents red. When all the waves are seen together, white light is seen. Next to the high-energy part of the visible region (400nm) is ultraviolet (UV) radiation. A common example of UV radiation is sunlight. Next to the low-energy part of the visible region (700nm) is infrared radiation (IR). An example of this kind of radiation is infrared heaters because they give out infrared radiation to heat a room. Click here for a great website giving information and examples of the different regions of the electromagnetic spectrum including radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma rays. 

The electromagnetic spectrum shows the different ranges of light. Many people think that the only form of light that exist is the light that we can see but this is not true. The visible region on the electromagnetic spectrum (400-700 nm) only accounts for a small portion of the electromagnetic spectrum. The regions with long wavelengths have low energy and the regions with short wavelengths have high energy. Along with wavelengths determining the energy, wavelengths also determine what color the light is. The electromagnetic spectrum represents a lot of information about the different forms of light.