Infra-red

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Infrared:

Anything that is 'hot' will emit electromagnetic radiation.

Radiation which is coming in may be reflected but some will be absorbed.

The materials electrons can also emit radiation, not much if cool, but lots if warm.

Humans have a temperature of 36.5-37.2 'C we therefore emit radiation with the peak in the infrared at around 9300nm (9.3UM)

How thermal imaging cameras work:

The camera's lens focuses on wavelength in the infrared part of the spectrum. They are focused onto a detector which detects infrared wavelengths this is then interpreted into a picture by sensor electronics.

Uses of infrared:

Detection of disturbed ground- (Police use this) Ground which may look fine to the naked eye will look disturbed in infra-red. Turned earth radiates heat differently to compacted soil so police can quickly find buried items e.g. money, weapons and bodies.

Night sounds- (This looks at wildlife and the different sounds that they make) Infra-red allows us to see in the dark, so we can figure out what the sounds are.

Weapon systems: Rifles can have infra-red sights to target enemies in complete darkness. Also used in conjunction with radar to guide anti-tank missiles. Pilots also use infra-red flares to distract heat seeking weapons.

Burgular alarms: 'learns' the normal temperature of the room, then detects if there are any changes to this room temperature.

Remote sensing satelites: Satelites detect reflected solar radiation.

Medicine: Whether you are looking for tumors or inflammation or infections, infra-red can provide the thermal evidence needed for a complete diagnosis it is also used to measure temperature.

Forensics: with infra-red light, investigators can tell you whether a document or money is forgery.. They can take a paint chip and tell you the make, model and age of a car. An infra-red profile of a sweaty fingerprint can reveal the age and gender of the person. Identify trace amounts of biological fluids

Engineering: Infra-red detects hot spots in machinery. When there is friction in machinery it creates heat and this makes it inefficient.

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