Black vs. White Socks
Name: Gary F.
This question will settle an argument between myself and
my wife and son (who agree against me). My son and I are basketball
referees. One day he was complaining that his feet were extremely hot
because he had worn black socks that day as opposed to white. He had
shoes on all day and long pants that covered the socks. I told him that
it did not matter if they were black or white, (assuming like materials
of course). I clarify long pants and shoes to eliminate heat absorption
from the sun, his socks being covered, along with the fact that we were
inside a gym all day. After reading the question from Dallas T. from
Saturday, April 20, 2002, I may even change my tune to think that his
black socks should even cool faster! Who is correct?
I cannot provide data which would help you win this argument; the data would have to be collected for
several individuals and several black vs. white sock manufacturers.
My inclination is to agree with YOUR argument against your son and wife. My suspicion is that for a given
set/type of sneaker/shoe, the temperature of the foot related to a sock would have more to do with the type
of sock fabric and its weave and less to do with its color. Certain fabrics absorb sweat, thereby pulling
it away from the body; their thickness and weave would
influence the amount of this which could occur. Some types of fabric have insulating properties, others do
not. Some fabrics, upon microscopic examination, could be seen to have a 'loose' weave with a lot of empty
air space, while others could be seen to have a
tight weave with less air space between threads.
I feel, but without supporting data, it would be incorrect to make a blanket statement relating resultant
foot temperature simply to the color of a sock. To me this would be like trying to estimate fuel economy
of a car based upon its color. Clearly there are factors which directly influence the observed data and my
reasons stated above cause me to doubt your wife and son's argument. As I said, however, to prove this
theory one would have to collect data eliminating variation in fabric/weave/thickness type and focusing
directly on color.
Thanks for using NEWTON!
Color has no effect that I can discern on conduction of heat. There are three ways for heat to move...
conduction, convection, and radiation. In the case of socks, the mode of heat transfer is by far
conduction. The type of fabric would be far and above the most important...cotton, wool, acrylic,
This is a difficult "experiment" to keep "everything else being the same" but if you think of the energy
inputs and outputs of feet, socks, shoes, and the rest of the world, body heat is by far the major heat
input to socks-on-feet, and evaporation of water from sweat is by far the major heat output at about 5.5
Kal /ml (here 5.5 Kal is "food calories" -- that corresponds to 5.5 k.cal thermal energy). What is
difficult to control, and I suspect is the case is, black socks and white socks are not the same fiber
content. The more hydrophobic the sock the more quickly water will evaporate from it (for example,
Polypropylene or Nylon fabrics dry much faster than cotton ). This is one of the reasons swim suits are
made from fibers like Nylon.
I cannot really settle your argument, but I have a couple of thoughts. He cannot really say that his feet
were hot due to the socks if he had nothing to compare with. Perhaps his feet were just really hot, or his
sneakers did not let his feet breathe. You have got to make it scientific. Get identical kinds of socks,
made by the same manufacturer, with the same fiber content, of the same thickness; the only difference
being the color. Wear one color on one foot and the other color on the other foot. Play all day,
then compare. My gut feeling, the black socks might have had more polyester or nylon in them. It does not
breathe as well as cotton. If you have already taken this into account, then you have blown my theory and
I do not have an answer.
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Update: June 2012