The Electromagnetic Spectrum 9th Grade What is the electromagnetic spectrum? The entire range of electromagnetic wave frequencies is called the electromagnetic spectrum. Radio Waves Are low frequency electromagnetic waves with wavelengths from less than a centimeter to about 1000 meters. Types of radio waves Microwaves are radio wavelengths of about 1 to 10 cm. Microwaves warm up food by making the molecules in the food vibrate at incredible speed. Sometimes the food is vibrated so fast that the food molecules tear and rip. Microwaves are absorbed by food, but the microwaves do not make the food radioactive because they turn into heat the minute they are absorbed by food. Radar In radar, radio waves bounce off an object to determine its speed and location. MRI In Magnetic Resonance Imaging (MRI), radio waves produce an image of the inside of the body. Infrared Waves Electromagnetic waves with a slightly higher frequency than radio waves People feel them as thermal energy or warmth Visible Light Has wavelengths between 390 and 770 billionth of a meter and can be seen with the eye ROYGBIV Red has the longest wavelength. Ultraviolet Light Have frequencies slightly higher than visible light and can damage skin Can kill bacteria Can be absorbed by some fluorescent materials and released as visible light. The Ozone Layer Absorbs most of the Sun’s harmful ultraviolet waves. X-rays and Gamma Rays Are ultra-high-frequency electromagnetic waves that can travel through matter, break molecular bonds, and damage cells. X-Rays are used to provide images of bones and to examine suitcases at airports without opening them. Radiation therapy is used to kill diseased cells.
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