Why does hot water clean dishes better than cold?

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That's my guess, anyway.

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Borodog,

You are going to consult some colleagues on this, right? SMP needs a definitive answer!

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Believe it or not, SMP has a bigger authority on this than Borodog. [img]/images/graemlins/smile.gif[/img] (not denigrating Boro, it's just that chemical engineers, in general, can answer this type of question better than astrophysicists)

There are 3 major reasons hot water works better than cold water in this situation, and all of them have been mentioned in this thread.

1. The biggest factor is that hotter water allows higher concentrations of detergent. That allows more surface interactions between the solid food, detergent and hot water.

2. Hotter water allows more water penetration into the dried food-stuffs on the plate (which again facilitates the surface interactions).

3. Diffusion rates are higher in hotter water. This means detergent molecules that do dissolve a lipid molecule from the dish surface are more easily transported to the bulk liquid.