Electromagnetic Spectrum A) The Waves of the Spectrum 1) EM spectrum: all of the frequencies or wavelengths of electromagnetic radiation 2) The EM spectrum includes radio waves, microwaves infrared rays, visible light, UV rays, X-rays, and gamma rays.

Electromagnetic waves Produced by the movement of electrically charged particles Can travel in a “vacuum” (they do NOT need a medium) Travel at the speed of light Also known as EM waves

B) Radio Waves -Longest wavelength -Lowest Frequency 1) Radio waves are used in radio & TV technologies, as well as in radar. a) Radio 1) Amplitude modulation (AM) 2) Frequency modulation (FM)

B) Radio Waves - Other uses b) Radar 1) Send out short bursts of radio waves that bounce off objects & return to receiver c) Cell phone communication d) TV broadcasting e) MRI (MAGNETIC RESONACE IMAGING) 1) Uses Short wave radio waves with a magnet to create an image

C) Microwaves -Shorter wavelength than radio waves -Higher frequency than radio, but lower than infrared 1) Only penetrate food at the surface

C) Microwaves - Other Uses 1.Bluetooth headsets 2.Broadband Wireless Internet 3.Radar 4.GPS

D) Infrared Waves -Shorter wavelength than microwaves -Higher frequency than microwaves, but lower than red light 1) Infrared rays are used as a source of heat & to discover areas of heat difference 2) You can’t see infrared radiation, but your skin feels its warmth

D) Infrared Waves Uses: – Night vision goggles – Remote controls – Heat-seeking missiles

E) Visible Light -Each wavelength corresponds to a specific frequency ** Color determined by frequency 1) People use visible light to see, help keep them safe, and to communicate with one another.

E) Visible Light 1. Only type of EM wave able to be detected by the human eye 2. Violet is the highest frequency light 3. Red light is the lowest frequency light

F) UV Rays -Shorter wavelength and higher frequency than violet light 1) UV rays have applications in health and medicine, and in agriculture. a) Helps skin produce Vit. D, can cause sunburn, cancer, and used to kill microorganisms

F) UV Rays Uses: – Black lights – Security images on money – Harmful to living things Used to sterilize medical equipment Too much causes sun burn Extremely high exposure can cause skin cancer

G) X-Rays -Shorter wavelength and higher frequency than UV rays 1) X-rays are used in medicine, industry, and transportation to make pictures of the inside of solid objects. a) X-rays are absorbed by solid objects (teeth, bones) & so solid objects appear white

H) Gamma Rays -Shortest wavelength -Highest frequency 1) Gamma rays are used in the medical field to kill cancer cells and to make pictures of the brain & in industrial situations as an inspection tool.

SUMMARIZE In a paragraph (5-8 sentences) summarize what you have learned about the EM spectrum.