Radiant Heat and Glass
Date: Spring 2014
What is radiant heat? Does glass transfer radiant heat?
Heat is energy transferring from one place to another because of temperature, because of random vibration of molecules. Conduction is molecules causing neighboring molecules to vibrate, energy moving one molecule at a time. Convection is molecules in a liquid or gas holding the energy as they flow to another location. An example is hot water coming out of a faucet to warm your hands. The water receives heat in the water heater, brings it up to the sink, and then gives it to your hands. The heat traveled from the water heater to your hands by convection.
Radiant heat, or radiation, does not need molecules to pass through space. Vibrating molecules emit the energy as electromagnetic radiation. Light from an incandescent light bulb is radiant heat. The warmth you feel when near a brightly glowing piece of metal is mostly radiant heat. Sunlight is radiant heat. If the glass allows the light to pass through, then radiant heat transfers through the glass.
Dr. Ken Mellendorf
Illinois Central College
Radiant heat is infrared radiation, which is electromagnetic radiation that has a longer wavelength than the human eye can detect. However, some of the shorter wavelengths are detected by the nerve endings in the skin as ?radiant heat?. There are optical instruments that can detect radiation in these wavelengths.
You have to remember that "glass" is not a pure substance. There are many types of glass depending upon the chemical composition of the "glass". Some glasses absorb infrared radiation "radiant heat" while other glass compositions transmit it. It all depends upon the composition of the glass.
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Update: November 2011