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Infrared Radiation

Infrared radiation is the transfer of energy from one place to another  by an electromagnetic wave.

IR wave

All objects emit and absorb infrared radiation. The hotter an object is the more energy it radiates per second.

Infrared radiation can travel through a vacuum. When infrared radiation hits an object some of the energy is absorbed, making the objects temperature increase, and some is reflected.

Different surfaces

Dark, matt surfaces are good absorbers and emitters of infrared radiation.

Light, shiny surfaces are poor absorbers and emitters of infrared radiation. An example of this is the silvering inside a vacuum flask.

black silver cans black silver graph

Uses of infrared radiation.

  • infrared heaters give out infrared radiation to heat a room
  • PIR’s (passive infra red devices), these can be found as part of home security alarm systems
  • thermal imaging cameras, police helicopters use these cameras to help find people when flying at night
  • the silvering on the inside of a vacuum flask helps prevent heat loss from coffee in the flask

Click this link to conduction & convection.