[neilep (OP)]

Dear Sanitationologist Palmists,



See this alcoholic skin sanitation stuff ?

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When I used some of this stuff on my hands  it made them feel nice and cool !

Why's that then ?.....and why is alcohol good for cleaning my hands anyway ..?


I want to know.....and ewe can tell me !


Thanks


Neil
Hand Cooling Enquirer

[Karen W.]

It is the evaporation from the alcohol that cools so quickly, because it evaporates so fast it has the effect..of bringing on the cooling..between the air and evaporization.. if it stayed on the hand longer it would warm up but it evaporates quickly causing a cooling.. at least that is my understanding of how it works.. I am no expert just a guess!

[lyner]

And why does evaporation involve cooling?
The molecules of the liquid have a range of speeds.
The faster ones have more than their fair share of the internal  (or heat) energy.
It's the fast ones which tend to leave the surface because they are more likely to break free from the bonds. Mostly they return and the energy is not lost but some of them are lost, along with their kinetic energy and the internal energy of the liquid is reduced. The temperature (average KE per molecule) is consequently lowered.
When air is flowing over the surface, more fast molecules are removed (they don't get a chance to fall back into the liquid) so cooling is quicker. You will notice that blowing on your hand cools you quicker. More 'volatile' liquids like alcohol cool you quicker because there is less energy binding the molecules and they are lost faster.

[Karen W.]

Thanks Sophie, That is part I can't remember well enough to explain...I remember a thread about why certain things are cooler on your skin.. spray things and it had a lot to do with what was used for the propellant.
And how like the size of the whole allowed for larger amounts of propellant..dictate the size of the spray droplets etc. and then the make up of the propellant.

I wondered because of the fact that this sanitizer was in a pump.... so it goes on in larger quantity where as a spray would allow a lot less sanitizer so
there would be a difference.. Thanks for the details. There was more then I remembered about it! []