By Janey Cavallaro
Electromagnetic Waves vs Mechanical Waves
Examples of the EM Spectrum
Microwave- Microwave radiation has a low frequency and a long wavelength. Most waves are absorbed by water, so when you heat up food in the microwave, the water in the food absorbs the radiation and causes the food to heat up. Microwave radiation is also used for cell phone signals. Some radiation can pass through the Earth's atmosphere and are used to transmit information to Earth's orbiting satellites.
Infrared- Infrared radiation is absorbed by skin. Humans recognize it as heat. These waves are also used in grills, heaters, and toasters. One example of a infrared radiation is night vision goggles. They pick up on the infrared radiation that our bodies give off and that is what allows you to be able to see. One final example is tv remotes. The frequency is higher than microwaves and radios, but still fairly low. As the frequency increases, the wavelength gets shorter. Another way infrared radiation helps us is it allows us to see the dust in space between stars.
EM Spectrum Continued
Ultraviolet Rays- Ultraviolet rays are found in sunlight. They are what make people tanner or in my case, sunburned. Your skin turns darker because your body is trying to reduce the amount of ultraviolet rays in your tissue. Ultraviolet radiation can often cause cancer. Ultraviolet rays are used in tanning beds and florescent lights. This type of radiation has high frequency and short wavelength.
X-Rays and Gamma Rays- Neither x-rays nor gamma rays can be seen or felt. X-rays are used to see if people have damaged bones. They can see through skin and soft tissue, but not bones and metal. Dentist use x-rays to check patients teeth. X-rays are also used at airports for security to check passengers bags. X-rays have high frequency and short wavelength. Gamma rays ave very high frequency and very short wavelength. Gamma radiation can pass through skin and tissue. They are often absorbed by cells. Gamma radiation is used to kill cancer cells, sterilize surgical tools, and kill harmful bacteria in food.