This blog entry is about electromagnetic waves, which most of us use every day, unles you live under a rock. But when you use them, you're probably not thinking, "Oh, I'm going to use some electromagnetic waves to do this thing that needs to get done." And if you are... well congratulations, you're probably the only one. There are seven. In order of wavelength from highest to lowest they are: Radio waves, microwaves, infrared, visible, ultraviolet, x-rays, and gamma-rays. One characteristic which all electromagnetic waves (EMS) share is that they are forms of radiation. Radiation is a form of energy which travels and spreads out, and therefore every type of wave in the EMS does so. Another very important characteristic is that EMS waves travel through matter. However, they don't need a medium, as they can travel through free space.
INFRARED
This is what we look like in infrared!
Profile:
Wavelength- 1X10^(-3) - 6X10^(-6) m
Frequency- 8X10^10 - 4X10^14 Hz
It sounds cool and sci-fi-like, doesn't it? However, our own skin emits infrared. Just out of visibility range, all warm bodies give off infrared. Warm things, like the sun and ourselves, give off infrared radiation and is taken in by colder things. Putting it simply, infrared is heat. The military uses it in night vision goggles to locate targets that they otherwise could not see, as I did when I was younger playing Secret Agent Barbie on the computer and had put on my night vision goggles to see people in hiding. You can also thank infrared waves when you change your TV channel to a less annoying show, otherwise you'd be watching that one forever.
X-RAYS
How embarrassing...
Profile:
Wavelength- 8X10^(-8) - 1X10^(-11) m
Frequency- 5X10^16 - 1X10^19 Hz
X-ray may be one of the types of EMS that you are more familiar with. If not, then you're probably due for a dentist appointment. If you've ever broken your arm, then you had an x-ray done of your mangled limb. It works because the x-rays go right through you, but since your bones are thicker, they are harder to penetrate and show the image of your skeleton that you see in the pictures your doctor probably showed you. Too much of this type of EMS is bad for you though, and that's why they put that heavy lead smock on the parts of that aren't being x-rayed. Bones are hard for the rays to get through, but lead is impossible. Outside of our world, the stars and the sun and other hot gases emit x-rays, and indeed the sun is mostly made up of x-rays.
Bibliography:
http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html
http://missionscience.nasa.gov/ems/01_intro.html
http://school.discoveryeducation.com/lessonplans/interact/electromagneticspectrum.html
http://roadtickle.com/10-cool-facts-about-the-human-body/
http://www.shutterstock.com/pic-2607953/stock-photo-x-ray-picture-of-human-torax.html
http://www.darvill.clara.net/emag/index.htm
