Radiant Heat Energy: Why is Hand Protected Behind Glass?

AI Thread Summary
Placing a hand behind glass does not allow it to feel radiant heat from a fireplace because glass is transparent to visible light but blocks infrared radiation, which carries heat. This phenomenon contrasts with sunlight, where glass allows infrared radiation to pass through, enabling heat sensation. The discussion highlights the greenhouse effect, where barriers like glass trap heat by allowing visible light in while preventing infrared radiation from escaping. This principle explains why energy enters during the day and is retained at night, leading to a temperature increase. Understanding these radiation spectra differences is crucial for grasping the relationship between heat transfer and the greenhouse effect.
westdivo
Messages
7
Reaction score
0
why does your hand not feel the radiant heat energy from a fireplace if you place it behind a sheet of glass, even though you can see the fire very easily?
 
Science news on Phys.org
I've never noticed that. Do you know the greenhouse effect?
 
Really? I doubt it.
Why can my hand feel the radiant heat from the sun if we place it under glass?

And what is the relation between the question and the greenhouse effect?
 
zlbeidou said:
what is the relation between the question and the greenhouse effect?

If you have a barrier (glass or atmosphere) that is opaque to infrared but transparent to visible light, it will let plenty of energy in during the day, and still block much of the heat-loss during the night. (The key is the differences between the radiation spectra from either side.)
 
Last edited:

Similar threads

I How Does Heat Transfer Impact Our Sensation of Temperature?
Replies
23
Views
2K
B Cooling effect of evaporation occurs even if the surroundings are colder?
Replies
10
Views
2K
Help understanding "Heat capacity"
Replies
28
Views
3K
Downgoing & Upgoing radiant heat equally reflected by RB?
Replies
2
Views
2K
B Opening this jar is made easier by cooling or heating?
Replies
8
Views
3K
How does evaporation generate cooling? Swamp coolers edition
Replies
32
Views
3K
A Average temperature in a greenhouse
Replies
2
Views
2K
B How accurate is the definition of heat?
Replies
15
Views
2K
Help me heat up a powder coating oven (made out of an old steel cabinet)
Replies
9
Views
2K
Construction Can a radiant barrier in the attic be effective?
Replies
26
Views
2K

Hot Threads

Recent Insights

Back
Top