There being a limit to how much I can obsess about quotidian
political trivia or opine about ideological arcana, I thought today I would
write about a scientific curiosity that has puzzled me for decades. I shall offer an explanation, and since I am a
philosopher by training, I shall attack this problem philosophically, which is
to say I shall address it by thinking about it rather than doing research.
The curiosity is this:
when I take a shower, I run the water until it is hot. Then I pull the little plunger atop the
bathtub faucet that switches the water to the shower head and wait a few
moments for the water to run hot. Then I
turn the water off, step into the bathtub, start the water again, and pull up
the plunger to start my shower. Even though I have waited
for the water to run hot, when the water hits me, for the slightest split
second it feels cold before it feels hot.
Why?
Here is my theory, carefully insulated from any actual facts. Temperature is essentially a measure of the
speed with which molecules are vibrating.
There is what we may call a microclimate around my body, consisting of
the first few molecules of oxygen, nitrogen, and so forth interacting with my
skin. Since under normal conditions my
body is hotter than the surrounding air, this microclimate’s temperature is
higher than that of the rest of the air in the bathroom. When the first bit of water from the shower
head hits me, it brushes away those molecules, and so for a split second the
microclimate around my body is actually cooled down. I experience this incorrectly as the water
being cold. Then the hot water warms up
the surface of my skin, and I feel warm.
This, presumably, is why even on a hot day a breeze feels
cool at first.
I should be glad to be corrected if someone reading this
blog actually knows something about the subject.
14 comments:
Unfortunately, I am not one of those people who might actually know about micro-climates around your body. But your idea seems reasonable to me. But I'm thinking there could be another explanation also. Everything we see, hear, feel through touch, etc. is really our brain's interpretation of signals sent to it from particular nerves. That interpretation can be wrong sometimes (you've seen some of those optical illusions I imagine). And the instant the water hits your skin is not the same instant that your brain figures out that it is warm water, even if you know ahead of time in an intellectual way that it is. And it might take some time for the brain to figure out what is actually happening to your skin even after it starts receiving some signals.
But this is all speculation also. Because I'm no expert on the brain either.
If your shower is like mine, the cold water that hits you is simply water that is in the metal hose that goes from the faucet to the shower head and has been there since the last time someone used the shower.
"Cold receptors primarily react to temperatures ranging from 68 to 86˚F, while warm receptors are activated between 86˚F and 104˚F. At extreme temperatures—below 60˚F and beyond 113˚F—the temperature signal is accompanied by a sensation of pain. Weirdly, researchers have discovered that at temperatures greater than 113˚F, some cold receptors can also fire. This phenomenon, known as paradoxical cold, has puzzled scientists for decades. No one is quite sure why the effect happens, since it doesn't seem to offer an evolutionary or adaptive benefit, says Barry Green, director of the John B. Pierce Laboratory and professor of surgery at Yale University School of Medicine. Today researchers are considering a wide array of interpretations of the strange sensation.
"The majority of scientists support the theory that paradoxical cold is a malfunction of the thermoreceptor system. Evidence suggests that pain receptors that respond to potentially harmful heat levels coexist on the same sensory fibers as cold thermoreceptors, says Lynette Jones, a senior research scientist at MIT. So when the nerve fiber sends a signal to the brain, it can sometimes be misinterpreted as a sensation of extreme cold. Paradoxical cold is the 'strange operation of a system under unusual stimulation conditions,' she says."
https://www.smithsonianmag.com/science-nature/why-does-very-hot-water-sometimes-feel-cold-180953532/
Wow! It's a thing!! That is super. Even though apparently no one knows why it happens, I feel as though I have been vindicated. At least I am not hallucinating.
To correct the former post...
If all this is true, why doesn't one feel cold every time one backs up away from the shower head flow (after one has been wet & hot for a while by the hot water) and then walks forward under the shower head flow again?
I think the metal pipe and shower head are cold after not using the shower between 12 to 24 hours of not using it. So the new hot water heat in the exposed shower head and connecting pipe get sucked out (through the process of conduction) since the shower head and exposed pipe are cold by being exposed to the bathroom air for so long. Now the pipe behind the shower wall doesn't have enough conduction to suck out the total heat of the hot water that was put there by running the hot water. But there is enough conduction to suck out the heat from the end of the shower head and exposed pipe. To use a biological analogy, we lose heat in our toes and fingers faster than other parts of our body first. Although I do admit that this analogy is not perfect since it is through radiation, air convection, and evaporation (and not really just conduction alone) that this occurs in our fingers and toes. I'm probably wrong about all of this though.
Felt measures of molecular kinetic energy can be so damn mean.
I think Michael Llenos explained it correctly. Before the "new" hot water reaches your body, it must first push out the older, cooler water that has been cooling down since the last shower.
To test this theory, jump in the shower immediately after Susie and see if you still feel cool water initially. I would doubt it.
No, no. I carefully run the shower for a while until it runs hot bwforee I get in.
As for JGKess, I love the sly humor!!!
How does the shower work? Do you have one knob for hot and one for cold? Or one knob for temp and another for on/off?
What happens if don't turn the water off before you get in? I.e. get the temperature right according to the bath faucet, then pull the plunger and wait long enough so that everything has reached its steady state, and then get in? That should give you that momentary cold feeling if your theory is correct (probably don't test the water after you pull the plunger to avoid biasing yourself).
Maybe a re-reading of Freud's "Scientific Project" is in order? Couldn't hurt!
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