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Author Topic: Why do I get less wet in a cold shower ?  (Read 7633 times)

Offline Ultima

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Why do I get less wet in a cold shower ?
« on: 11/04/2005 11:13:16 »
Hey everyone,

The shower in my flat has been busted for a couple of days, so I've been having cold showers in the morning... I've noticed that I come out bone dry compared to a hot shower??? I was just wondering if there is some sort of reason for this? It's not because I'm dashing in and out whilst screaming from the cold ;)! Does cold water run faster than hot? I figured hot water would evaporate faster etc.. I might just be imagining things.

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Offline sixelms

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Re: Why do I get less wet in a cold shower ?
« Reply #1 on: 11/04/2005 13:06:17 »
I bet you it's because your pores close up under the coldness of the water, so that when you've finished your shower the water just falls off.
 

Offline Ultima

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Re: Why do I get less wet in a cold shower ?
« Reply #2 on: 11/04/2005 15:08:01 »
yeah and maybe goose bumbs are more hydrodynamic :D

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Offline Calum

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Re: Why do I get less wet in a cold shower ?
« Reply #3 on: 11/04/2005 20:45:04 »
Less water vapour around maybe?
 

Offline daveshorts

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Re: Why do I get less wet in a cold shower ?
« Reply #4 on: 11/04/2005 22:06:53 »
It could be a couple of things:



 Also the surface tension of water reduces with temperature,  according to  http://www.millenium-new.com/SKW/uk-egenskaber.html by 22% from 0C to 100C (the energy of the molecules starts to get larger relative to the intermolecular forces so they are more likely to wander off and wet surfaces. This means that the water is more likely to wet your skin and less likely to sit as beads on the surface, and then run off easily.

Also because it has a lower surface tension hot water is much better at removing greese than cold water, so you may remove more of the oily layer on your skin in a hot shower (ask a medic for its name) so you may become less water repellant, so the water is even less likely to run off.

I am not sure which of these effects dominates
 

Offline Ultima

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Re: Why do I get less wet in a cold shower ?
« Reply #5 on: 11/04/2005 22:24:10 »
So I might not be imagining things then :D YAY. I might try an experiment with weighing my towel or something, with hot and cold water. But I don’t have any scales… so the first scientific challenge is to make and calibrate some ;) I do have a measuring jug though, 1 Litre of distilled water = 1 Kg yeah???

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« Last Edit: 11/04/2005 22:27:55 by Ultima »
 

Offline daveshorts

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Re: Why do I get less wet in a cold shower ?
« Reply #6 on: 11/04/2005 23:35:01 »
I am not sure if it is a real effect, but it may be related.

 I have noticed that on really cold mornings (in uk so not quite freezing) water lying on the ground looks really wierd, it seems to be a film with lumps in it like it is trying to form droplets but failing to, I don't think the lumps are ice (as I poked them and they didn't seem to be), but I can't think of any other reason for them being lumps... has anyone else noticed this? It may be a related wierd surface tension effect...
 

Offline OldMan

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Re: Why do I get less wet in a cold shower ?
« Reply #7 on: 12/04/2005 03:50:08 »
I'm thinking it would have some what to do with humidity and body temperature. Think about it this way, you have a hot shower when it is really humid and it is hard to get dry as the air is holding a lot of moisture and you probably sweat a bit as well in the warmth of the room. Now if you finish a shower on a humid day with a decent blast of cold water it is a lot easier to get dry at least at first, I'm guessing because your external body temperature is lower than if you'd just stepped out of a steaming hot shower, therefore you not going to be sweating as much and maybe the water vapour doesn't condense on you as easily.

actually I'm not really sure but it was worth a crack, I think part of the answer is some what related to that.

Tim
 

Offline Tronix

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Re: Why do I get less wet in a cold shower ?
« Reply #8 on: 12/04/2005 14:04:36 »
I have found that i dry off quicker from hot showers really, as the water just evaporates off me. But then again, i only use the towel to dry my hair. As for cold showers, i think they dry off just as quickly. Now room temperature seems to be the tricky one.

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Offline chris

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Re: Why do I get less wet in a cold shower ?
« Reply #9 on: 13/04/2005 17:54:36 »
The answer from Dave is the correct on. Hot water is much less viscous (sticky) than colder water - you can see the difference for yourself if you pour a mug of boiling water into the sink and compare the sound it makes when you pour away a mugful of cold water.

As the temperature of the water rises the molecules zip about much more quickly making it harder for them to stick together through the process of hydrogen bonding. Cold water, being stickier, is more likely to form larger blobs of water on your skin which simply run off en-masse when you turn the taps off.

Also, the other point made by Dave referred to the skin's greasy layer, called sebum, which makes us all a bit water repellent. A hot shower will transfer heat to the sebum, making it runnier and more likely to slide off, making you less water repellent and increasing the amount of water that can sit on the skin surface. A cold shower will be less effective at dispersing the sebum, so you'll hold onto less shower water after you step out of the tray.

Chris



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Offline Ultima

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Re: Why do I get less wet in a cold shower ?
« Reply #10 on: 14/04/2005 09:39:36 »
Yay thanks for the replies, sorry I was away working hard at uni work (like students always do ;)). Yeah all those explanations sound very reasonable to me... If only I could get a hot shower to compare with :D, Another great question is what does the tenant-landlord act say about getting stuff fixed?

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Offline neilep

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Re: Why do I get less wet in a cold shower ?
« Reply #11 on: 17/04/2005 18:47:21 »
Matt, why don't you just run a hose from your kitchen sink ?... get a bit of scaffolding,  locate a make do shower head from a watering can, get someone to turn the tap on and off very quickly for the pulse effect,  use an intercom to communicate instructions to the tap controller....simple !!..I don't see what the fuss is about at all.

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Offline daveshorts

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Re: Why do I get less wet in a cold shower ?
« Reply #12 on: 09/05/2005 12:24:47 »
I just tried running water from a hot water tap and a cold water tap over the back of my hands, and it was very noticible that the hot water was wetting my hand better. Try it it is easy (if a little painful if the hot water is too hot)

It was so quick I would doubt that it is to do with moving the oils so it is probably just altering the surface tension of the water - especially as the hot water side goes into globules as it cools down.
 

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Re: Why do I get less wet in a cold shower ?
« Reply #12 on: 09/05/2005 12:24:47 »

 

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