Temperature and color - why hot objects glow red?

In summary, objects that are heated emit higher energetic radiations, starting with Infra-Red and changing to Red, Orange, Yellow, White, Blue, and UV as the temperature increases. This is known as the thermic radiation spectrum and is described by Planck's law of black body radiation. Touching a piece of steel that is red can still be dangerous, as red represents a lower temperature compared to blue, which represents a higher temperature.
  • #1
i.mehrzad
84
0
Is there any reason why most hot things alost always begin to get the tinge of red??
 
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  • #2
hi mehrzad...yeah there is a reason...it is related to their thermic radiation spectrum...when you heat up an object like a piece of iron...it will emit higher energetic radiations...from Infra-Red it changes to Red...then Orange...Yellow...White...Blue...UV...and so on

(wavelength peak)=(B)/(Temperature)----»for a blackbody
 
  • #4
if you want to know more about this branch of thermodynamics...look for ultraviolet catastrophe, it's interesting
 
  • #5
Remember red is cold and blue is hot. I still don't recommend touching a piece of steel that is red.

CraigD, AMInstP
www.cymek.com
 

1. Why do hot objects glow red?

Hot objects glow red because of a phenomenon called thermal radiation. When an object is heated, it emits electromagnetic radiation in the form of light. As the object's temperature increases, the wavelength of the emitted light decreases, causing the color to shift from infrared to red, and eventually to white.

2. What is the relationship between temperature and color in hot objects?

The relationship between temperature and color in hot objects is based on the object's blackbody radiation. As the temperature of an object increases, it emits more light and at shorter wavelengths. This causes the color to shift from red to orange, yellow, white, and eventually blue as the temperature continues to rise.

3. Why does the color of a hot object change as its temperature increases?

The color of a hot object changes as its temperature increases due to the change in the object's blackbody radiation. As the temperature increases, the object emits more light and at shorter wavelengths, causing the color to shift from red to white. This is known as the Planckian locus, which describes the relationship between temperature and color in a blackbody radiator.

4. Is the color of a hot object always a reliable indicator of its temperature?

No, the color of a hot object is not always a reliable indicator of its temperature. This is because the color of an object is also affected by its emissivity, which is a measure of how efficiently an object emits thermal radiation. Objects with a low emissivity may not emit as much light at a given temperature, causing the color to appear cooler than it actually is.

5. Why do hot objects emit different colors at different temperatures?

Hot objects emit different colors at different temperatures because of their varying blackbody radiation. As the temperature of an object increases, the wavelength of the emitted light decreases, causing the color to shift from infrared to red, and eventually to white. This phenomenon is described by the Planckian locus, which shows the relationship between temperature and color in a blackbody radiator.

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