common applications of radiation

1.teapots

Since shiny surfaces are bad emitters of radiation, shiny teapots can keep tea warmer than a black teapot for a longer time. In addition, since shiny surfaces are bad absorbers of radiation, shiny containers can keep a cold liquid cooler for a longer time than black containers.

2.Greenhouse

The greenhouse traps heat to help plants grow better. On a warm day, infra-red radiation from the Sun passes through the glass of the greenhouse and is absorbed by the soil and plants inside. The soil and the plants therefore become warmer and they emit infra-red radiation of longer wavelengths. These longer wavelengths of radiation are unable to pass through the glass and so heat is trapped inside the greenhouse. This causes the temperature inside the greenhouse to rise and this is good for plant growth.

3.Vacuum flasks

It is designed to keep liquids hot by minimising heat losses in 4 possible ways-Conduction, Convection, Radiation and Evaporation.
Conduction and covection through the sides of the flask are prevented by the vacuum between the double-glass walls of the flask. Conduction through the trapped air above the liquid is mionimal since air is a very poor conductor of heat. The stopper is made of plastic which is also a poor conductor of heat.
Convection and evaporation can only occur when the plastic stopper is removed during use. Heat loss by radiation is harder to stop as radiant heat can pass through vacuum.
The minimise heat loss through radiation, the walls of the glass are silvered to reflect the radiant heat back into the hot liquid.