Microwaves have a low electromagnetic spectrum. The electromagnetic spectrum is the set of all possible electrical radiations. The frequency of a wave is the number of waves per second, and the frequency of a microwave is between 300 MHz and 300 GHz. The wavelength of a wave is the distance from a peak of a wave to the peak of a subsequent wave and the wavelength of a microwave varies from one millimeter to thirty centimeters. Frequencies range from ultra high frequency to super high frequency to extremely high frequency. The microwave was discovered by Heinrich Hertz and predicted by James Clerk Maxwell. In 1864, James Clerk Maxwell theorized about microwaves until he predicted the equations that would prove the existence of microwaves. In 1888 Heinrich Hertz took these equations and used them in an experiment. He made an apparatus that produced waves and detected these waves. The experiment showed the different wavelengths of some waves, such as the short wavelength of microwaves. The discovery of microwaves allowed their use for commercial purposes. Microwave ovens are the best example of commercial use of microwaves. Microwave ovens use microwaves at a frequency of 2450 MHz. The microwaves travel and vibrate the water, fat and sugars, causing the temperature of the food to rise. This type of energy is called dielectric energy. This benefits the food preparation process and anyone purchasing TV dinners. Another example of microwaves are cell phones. Cell phones use an antenna and a small transmitter to connect to microwaves emitted into the air. To make cell phones more attractive to buyers, they kept the transmitters and antennas to a minimum. Microwaves used in telephones allow a person to receive calls from anywhere, this is especially important in an emergency. Radio and television broadcasts, such as cable TV and the Internet, use microwaves to transmit the signal in order to broadcast. These two sources using microwaves allow for faster communications between all areas of the world. These two sources using microwaves are the most popular modes of entertainment in most of the United States. The commercial industry benefits from these products that use microwaves. Current studies are undecided about the effects of microwaves. Microwave ovens can cause eye damage. If a person presses their face on the microwave oven, it can cause cataracts in the eyes. The best advice to protect yourself from this effect is to stay a couple of meters away according to Dr.