Radiation: All objects emit (give out) radiation (heat energy).
all objects that are hotter than its surroundings emit more radiation than it absorbs. (as it cools down). The oppiste is for the objects that are cooler than its surroundings.
the hotter the object the more radiation it emits in a given time.
Shiny surfaces reflect infared radiation but are poor emitter and absorbers
Dark matt surfaces emit and absorb radiation but are poor reflecters
solar pannels, water pipes dark surfaces, suns heat energy is absorbed to heat water pipes, water can be used for washing or heating building.