Wavelength
Wavelength diagram showing a blue line going up and down and then up again

Radio waves, television waves and microwaves have different wavelengths. Image Credit: NASA

      the distance between one peak or crest of a wave of light, heat, or other energy and the next peak or crest




Sentences:
NASA's satellites study different wavelengths of light from space.

Wavelengths can look like waves in the ocean; and just like in the ocean, some are small and others are huge.



More Information:
http://www.nasa.gov/audience/forstudents/k-4/dictionary/Electromagnetic_Spectrum.html
http://science.hq.nasa.gov/kids/imagers/ems/ems.html   →
http://science.hq.nasa.gov/kids/imagers/ems/waves3.html   →