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View Full Version : Was thinking about this the other day...



Champion_Munch
2005-Aug-17, 01:45 PM
In the 'visible' part of the electromagnetic spectrum, red light has a longer wavelength than opposing colour blue. Stars that have red surfaces are also alot cooler than stars with blue surfaces; red is of course an indication of a much cooler object than blue is.

So why do we (as humans) usually associate blue as cold and red as hot, when it is clearly the opposite?

with regards

CJSF
2005-Aug-17, 01:52 PM
In the 'visible' part of the electromagnetic spectrum, red light has a longer wavelength than opposing colour blue. Stars that have red surfaces are also alot cooler than stars with blue surfaces; red is of course an indication of a much cooler object than blue is.

So why do we (as humans) usually associate blue as cold and red as hot, when it is clearly the opposite?

with regards

In my opinion,

Probably because, for most of human existence, even until relatively recently, the hottest things a person experienced glowed red or orange (fire, hot coals, etc). Blue flames would have been rare, I think. Also, ice and snow tend to appear bluish, particulary in shadows or in low light. Water also tends to look blue or blue-green.

CJSF

ngc3314
2005-Aug-17, 01:53 PM
In the 'visible' part of the electromagnetic spectrum, red light has a longer wavelength than opposing colour blue. Stars that have red surfaces are also alot cooler than stars with blue surfaces; red is of course an indication of a much cooler object than blue is.

So why do we (as humans) usually associate blue as cold and red as hot, when it is clearly the opposite?

I've wondered about that too. I suspect it comes from our lack of experience with things more than red-hot. Plenty of associations of red with heat - firelight in particular. Maybe by comparison, ice seems bluish (big question mark), and outdoor ice may well appear so from reflected sky light.

Physicists are known to get quite unexpected results from the water taps in hotels labelled only with red or blue dots, since red should clearly be the cold tap. (No names here).

Gillianren
2005-Aug-17, 05:08 PM
there was a mystery novel I read as a child (well, novel may be pushing it, but picture book, anyway) wherein the fact that the taps were labelled in Spanish ("c" meaning "caliente," or "hot") was the clue.

but on topic, well, add a "me too." if you've ever looked, snow has blue shadows. there is a colour called "ice blue," whereas I know of no "ice red." blue and green, albeit in pastel, are fairly common colours in a snowscape. and while we know that blue is hot, blue is also obviously cold, and red makes a nice contrast.

El_Spectre
2005-Sep-06, 06:05 AM
In the 'visible' part of the electromagnetic spectrum, red light has a longer wavelength than opposing colour blue. Stars that have red surfaces are also alot cooler than stars with blue surfaces; red is of course an indication of a much cooler object than blue is.

So why do we (as humans) usually associate blue as cold and red as hot, when it is clearly the opposite?

with regards

Well, fire is hot and water/ice is cold, so...

Alternately, consider the organisms that live around those deep sea thermal vents (black smokers)... to them (ok, ok... if they weren't all blind) black would mean "hot".

Matthew
2005-Sep-06, 07:37 AM
Its now been deeply ingrained in our phsychology. Also if you heat up a piece of metal, it'll start glowing red, then yellow, but not then blue. The color becomes white. In medieval times before we knew about "frequencies" there would have been some instances when metals would have become white-hot.

pumpkinpie
2005-Sep-07, 05:17 PM
Along the same lines.....when you send light through a prism and measure each color individually, isn't red at a higher temperature than blue/violet? Why is that? :confused:

Champion_Munch
2005-Sep-17, 11:31 AM
Yeah, that seems to make sense I guess. :) Still think it's pretty ironic. :P

with regards

Titana
2005-Sep-18, 11:39 PM
Its now been deeply ingrained in our phsychology. Also if you heat up a piece of metal, it'll start glowing red, then yellow, but not then blue. The color becomes white. In medieval times before we knew about "frequencies" there would have been some instances when metals would have become white-hot.


Truly agree, the main point is its been deeply ingrained in our phsychology..


Titana.........

Charlie in Dayton
2005-Sep-19, 04:20 AM
When you're overheated, you turn red...and when you're freezing yer gender off, you turn blue...