The Electromagnetic Spectrum

Waves of the electromagnetic spectrum are all around you. Some come from sources in outer space. Others come from sources on Earth such as radio and TV transmitters, microwave ovens, x-ray machines, and remote control devices. Some wavelengths are visible—but most are not. Where does visible light fit into the spectrum?

To learn more about the electromagnetic spectrum, follow steps A–C below.

1. To view the sources of electromagnetic waves, go to Electromagnetic Waves. On the left side of the diagram you will see characteristics of waves. We will be looking at the size of the wavelength, the common name of the waves, and the sources.
2. Use the illustrations of the spectrum to answer the following questions on a separate piece of paper.
   1. Which type of wave has the longest wavelength?
   2. Which type of wave has the shortest wavelength?
   3. What kind of waves provide the energy to make your morning toast?
   4. Which type of wave has a wavelength approximately the size of a bullfrog?
   5. What type of waves does a cellular telephone use?
   6. Name a use for gamma rays.
3. When you are finished, check your answers.

Further Exploration

What are cosmic rays? Do they fit into the electromagnetic spectrum? Explore NASA's interactive Cosmic Rays and Supernova Dust page to find out more about cosmic rays.