Why is hot water more effective than cold when washing your hands, if the water isnt hot enough to kill bacteria?

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Why is hot water more effective than cold when washing your hands, if the water isnt hot enough to kill bacteria?

In: Chemistry

No but warmer water is enough to open pores and get some soap into there. That’s why a rule of thumb when dealing with bodily fluids on your hands (someone else’s fluids), cold water is recommended because it doesn’t open them.

Because you’re more likely to wash your hands longer if the water is warm. Longer wash means more coverage and better germ killage.

Most things are more soluble in warmer water. The stuff you want to remove from your hands dissolves in the water, and is also dissolved by the soap.

Interesting comments so far.

I recall a recent study showing that cold water was as effective as hot water for cleaning hands.

I would have expected warmer water to better dissolve organic (carbon containing) compounds.

The study proved that the difference was insignificant; I guess I was wrong.

It’s not. [Here’s an article by Australia’s science outreach guru, Dr Karl](https://www.abc.net.au/science/articles/2010/09/23/3020122.htm) (think Bill Nye but with less hair and a more complex last name). TLDR: Soap actually works better at body temperature (which is not hot). When water of any temperature is in contact with your body, it tends to cool or heat to (you guessed it) body temperature. The temperature of the water has been scientifically proven to do almost nothing to the effectiveness of washing – in some soaps, warm water actually *causes* issues.