There are many waves on the electromagnetic spectrum and without knowledge of how all of these waves work we wouldn't be quite as advanced as we are today. Infrared waves are used for many things in our world, Infrared photography and laser eye surgery are just two of the many uses of infrared radiation. Infrared waves are used in heat transfer and are essential to the Greenhouse Effect also.
An infrared wavelengh is about 0.1 to o.oooo75 cm long. It's frequesncy range is anywhere from 10^12 to 5 x 10^14. Accodrding to Adustum, infrared radiation is absorbed and emitted by the vibrations of atoms of many materials. Glass windows and other types of matter absorb infrared light waves, also after spending time in the sun infrared light waves can be felt as warmth on the skin, infrared light is not visable. Most objects on Earth emit infrared waves, everything above zero degrees celcius has infrared radiation. The main source of infrared radiation is in heat radiation, the warmer something is, the more moving molecules they produce resulting in more infrared radiation. Infrared waves are also a vital part of the Greenhouse Effect. The Greenhouse Effect is the warming of the Earth's surface, infrared radiation gets absorbed by Earth's atmosphere causing the atmosphere to heat up. This causes infrared radiation to return to Earth's surface.
There are many uses for infrared waves such as infrared photography. Infrared photography is when infrared rays are used to reflect off of a surface to show light. The rays detect heat, warmer things such as a human would appear very bright, but something such as a lake would appear almost black. Also infrared rays are used by the military to detect objects and people in the dark. Lasers are also very known uses for infrared rays, carbon dioxide or carbon monoxide is used with infrared rays to create the lasers.
Infrared waves are hot so be sure not to be over-exposed with infrared waves because they can cause burns but infrared waves are otherwise safe. Infrared waves are an important part of the electromagnetic spectrum. They are used for photography, the military, lasers, and for many other interesting things. They also account for nearly 50% of the Sun's radiant energy. Without infrared waves the world would be a very cold and different place.
Photos: http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/what_is_ir.html
Other sources:
http://www.school.eb.com/eb/article-59183?query=infrared%20frequency%20range&ct
http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/what_is_ir.html
http://library.thinkquest.org/27930/spectrum.htm
http://library.thinkquest.org/C006027/html-ver/es-infra.html
