Radiant Heat Energy: Why is Hand Protected Behind Glass?

In summary, the reason your hand does not feel the radiant heat from a fireplace when placed behind a sheet of glass is because glass is opaque to infrared but transparent to visible light. This is similar to the greenhouse effect, where the atmosphere traps heat but allows visible light to pass through. This also explains why your hand can feel radiant heat from the sun when placed under glass.
  • #1
westdivo
7
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?
 
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  • #2
I've never noticed that. Do you know the greenhouse effect?
 
  • #3
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?
 
  • #4
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.)
 
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Related to Radiant Heat Energy: Why is Hand Protected Behind Glass?

1. What is radiant heat energy?

Radiant heat energy is a form of energy that is transferred through electromagnetic waves. It does not require a medium, such as air or water, to travel and can move through vacuum.

2. Why is hand protected behind glass?

Hand is protected behind glass because glass is a poor conductor of heat and can block the transfer of radiant heat energy. This prevents burns or other injuries that can occur from direct exposure to radiant heat.

3. How does radiant heat energy affect humans?

Radiant heat energy can affect humans by causing burns or other injuries if exposed to high levels for a long period of time. However, it can also be beneficial, as it provides warmth and comfort.

4. What are some common sources of radiant heat energy?

Some common sources of radiant heat energy include the sun, fire, heated objects, and electric heaters.

5. How can we measure radiant heat energy?

Radiant heat energy can be measured using instruments such as infrared thermometers, pyrometers, and heat flux sensors. These devices measure the amount of radiation emitted by an object and convert it into a temperature reading.

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