Changes

The Electromagnetic Spectrum is the entire range of electromagnetic radiation extending in frequency from zero Hertz to 10²³ cycles per second (or Hertz).<ref>http://science.nasa.gov/newhome/help/glossfig1.htm</ref>

The Electromagnetic Spectrum is the entire range of electromagnetic radiation extending in frequency from zero Hertz to 10²³ cycles per second (or Hertz).<ref>http://science.nasa.gov/newhome/help/glossfig1.htm</ref>

Longer wavelengths of electromagnetic radiation have lower frequencies have such as AM radio (540 to 1600 KHz). FM radio has much shorter wavelengths and higher frequencies (88 to 108 MHz).  

Longer wavelengths of electromagnetic radiation such as used in AM radio have lower frequencies (540 to 1600 KHz). FM radio has much shorter wavelengths and higher frequencies (88 to 108 MHz).  

Even higher frequencies give as microwave radiation, used in Radar and cooking. Still higher is infrared (which can keep food warm from a lamp or heat up your skin from sunlight or fire). Infrared is used in "black light" photography.

Even higher frequencies give as microwave radiation, used in radar and cooking. Still higher is infrared (which can keep food warm from a lamp or heat up your skin from sunlight or fire). Infrared is used in "black light" photography.

Next highest in frequency (and lower in wavelengths) is [[visible light]]: red, orange, yellow, green, blue, indigo and violet.  

Next highest in frequency (and lower in wavelengths) is [[visible light]]: red, orange, yellow, green, blue, indigo and violet.