infrared and temperature

• every object absorbs and emits infrared radiation. infrared is emitted from the surface of the object
• the hotter an object is, the more infrared radiation it radiates in a given time
• an object that is hotter than its surrounding emits more IR radiation than it absorbs as it cools down. an object that is cooler than its surrounding absorbs more IR radiation than it emits as it warms up
• objects at a constant temperature emit infrared radiation at the same rate that they are absorbing it
• a black surface is better at absorbing and emitting radiation than a white one, and a matt surface is better at absorbing and emitting radiation than a shiny one