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| From: JOhn |
30/11/2000
11:41:17
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| Subject: red hot metal |
post id:
178842
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Hiya Karl,
I know it's
late but this should be an easy one. How come hot metal always glows the
same colour? It seems that nearly all metals, if heated, will glow red?
Love to hear what you have to say on this one.
Kind
regards
John
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| From: B.C. ® |
30/11/2000
13:14:11
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| Subject: re: red hot metal |
post id:
178932
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,metals do glow different colours
depending on what temperature you heat them up to.They can go through a
series of colour changes from dull straw up to red and
orange,
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| From: MichaelT |
30/11/2000
15:26:01
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| Subject: re: red hot metal |
post id:
179062
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Red light is low energy
output. As more energy is put into the metal, the colour becomes lighter
due to higher light energies being released. You can theoretically get the
metal to the point where it is giving off white light, and off into the
blues even, although it probably would have vaporised well before this
point.
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| From: Terry Frankcombe
(Avatar) |
30/11/2000
18:12:47
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| Subject: re: red hot metal |
post id:
179156
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It's all to do with black body
radiation. Objects emit radiation approximately according to the black
body radiation law, which gives the frequency at which the emmission
maximum occurs depending on the temperature. As the temperature goes up,
so does the frequency of the emmited radiation. Normally this sits well
into the infra red, but as a significant amount of the radiation starts
coming out in the visible spectrum the thing goes red (as this is the
lowest energy bit of the visible light
spectrum).
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| From: Alan™ ® |
30/11/2000
18:23:49
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| Subject: re: red hot metal |
post id:
179165
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Having worked alot with molten
metal. I believe that the red glow observed is more an intrinsic property
of the particular metal. At 800°C iron alloys do have a definite red glow,
but this is the temperature where aluminium is poured. Aluminium at 800°C
is definitely metallic silver and has no red
glow.
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