MadSci Network: Physics |
Thank you for your question. Color is perceived - thanks to remarkable construction of the human eye and optic nerve. So first, I want to mention some basics of color and its relationship to heat. We perceive the color white if all wavelengths of light are equally reflected - our eye "integrates" the color spectrum. If something absorbs at a particular wavelength, leaving (say) red and green - the human eye perceives it as yellow, even though the wavelengths spectrally are a combination of red and green. So what we call color, is simply electromagnetic radiation of a particular wavelength. What we perceive as color (with our eyes) may be electromagnetic radiation of that wavelength or it may be a combination of other wavelengths which the eye integrates to perceive a particular color. Next, the relationship between heat and light. Heat is just another form of electromagnetic energy. For an perfect radiator, the spectrum of wavelengths emitted due to temperature is given by the Planck equation (see, for reference: http://physics.scsu.edu/~dms/cosmology/bBodyLessons/bb.html ). It is important to note that these "colors" are not limited to the relatively narrow band in which the human eye operates. Nevertheless, the thermal stimulation of the atoms and electrons emit electromagnetic radiation characteristic of its temperature. The sun for example has a surface temperature of a little less than 6000 degrees Kelvin. It peaks at around 550 nanometers (yellow), which remarkably is the peak response of the human eye! Anyway, I hope this helps explain color/heat a little better. I've added a couple of links here which go into a little more detail. 934381368.Ph.r.html http://www.micro.magnet.fsu.edu/primer/java/colortemperature/index.html
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