Black t shirts and blackbodies

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Main Question or Discussion Point

Wearing black at night...is it true that wearing a black t shirt on a hot night at night will make you cooler than a white t shirt? Has this got anything to do with blackbody radiation?
 

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  • #2
haruspex
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Wearing black at night...is it true that wearing a black t shirt on a hot night at night will make you cooler than a white t shirt? Has this got anything to do with blackbody radiation?
I would think it depends on a couple of things... how hot the surroundings are and whether it is 'black' at infrared wavelengths.
In a hot dry environment, above body temperature, it might be more important to keep thermal radiation out. Your sweat will cool you down.
 
  • #3
the idea is that black colour dissapates heat faster,
the concept stems from the below example

in desert nations, workers dress as to how often thier in the shade
if your walking from shady spot to shady spot, and spending time in that shade
you wear dark colours, you get sweaty cause of the layers but in the shade
you cool faster as the wind blows through

likewise if your is the sun alot you wear light coloured clothes to not absorb as much heat
and the wind blowing through your clothes evaporates the sweat and circulates a cooler air
about your body

but its the wind powerd evaporation thats doing the most of the cooling

at night your not dealing with solar radiant absorption, but keeping your body from absorbing heat
from the air or nearby warm objects
again wind and evaporation is going to be the major factor

so, yes a black shirt will shed heat faster than a white one, but in the instance of clothes
the differance is very minimal, perhaps unnoticable

now if you change the question to "will a steel body car..."
the metal of the black car should cool off faster in the shade/dark than a white car
at a noticable degree of diferance

but theres always the factor of airflow, cause if theres no airflow, the lingering warmth
means a slower/longer cooldown time
 
  • #4
Drakkith
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the idea is that black colour dissapates heat faster,
Remember that just because something is black does not mean that it is a good emitter of far infrared radiation.
 

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