The Electromagnetic Spectrum: Radio Waves

By: Hannah Kimball, Ilana Ruben, and Ella Cohen

Wavelength

• Radio Waves have the longest wavelength of any wave on the Electromagnetic Spectrum.

• Radio Waves have wavelengths from infinity to 3 x 10-1 meters.

Frequency

• Radio Waves are the least energetic type of wave on the Electromagnetic Spectrum.

• Radio Waves have a frequency between

1 x 104 Hertz to 1 x 108 Hertz.

• Radio Waves can be found on the left end of the Electromagnetic Spectrum right next to Microwaves.

Uses and Applications

Radio Waves are useful for:• Radios and Cell phones• Televisions• Ships• Airplanes• Police and Radar• Satellites

Visibility/Human Effects

• Radio Waves are not visible to humans or any other type of organism.

• Radio Waves are potentially damaging to humans. – Cell phones may cause brain tumors.– Radio Waves may raise your body

temperature.– Radio Waves may damage your eyes.

Discovery

• Radio Waves were discovered by Heinrich Rudolf Hertz in around 1885.

• He conducted an experiment using a ‘transmitter’ (a pair of metal rods with a gap between the two ends that are connected at the other ends to terminals of induction coils).

• Using this device and other experiments, H. R. Hertz proved that radiation moves in wave pattern similar to light.

Other Interesting Facts

• The Federal Communications Commission (FCC) controls and regulates the use of Radio Waves to prevent communication overload and interference.

• Radio Waves travel at the speed of light.

• A radio picks up Radio Waves and turns the electrical signal into sound.

Other Interesting Facts, cont.

• There are two main types of Radio Waves:– AM (Amplitude Modulation) where the amplitude of

the waves changes to match the signal from the radio station.

– FM (Frequency Modulation) where the frequency changes to match the signal from the radio station.

• “Mobile phones could kill far more people than smoking or asbestos, a study by an award winning cancer expert has concluded.”1

1 “Mobile Phones ‘more Dangerous than Smoking’-. “Web. 07 May 2010. http://www.independent.co.uk/life-style/health-and-families/health-news/mobile-phones-more-dangerous-than-smoking-802602.html.

The MOST Interesting Fact

• Radio Waves can be longer than a football field or shorter than a football!

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"Mobile Phones 'more Dangerous than Smoking' -." Web. 07 May 2010. <http://www.independent.co.uk/life-style/health-and-families/health-news/mobile-phones-more-dangerous-than-smoking-802602.html>.

"Radio Wave." The World Book Student Discovery Science Encyclopedia. Chicago: World Book, 2006. 148. Print.

"Radio Waves." NASA Science. Web. 07 May 2010. <http://science.hq.nasa.gov/kids/imagers/ems/radio.html>.