Re: Why does hot water clean dishes better than cold?
Hi,
Try a simple experiment with your niece. It'll be fun, and she'll love it. And you didn't say the age of your niece, but I'm assuming pretty young, considering the question.
Take 4 glass containers. Put hot tap water in 2 of them and cold tap water in the other 2.
Now for the other ingredients. 2 equal pats of butter/margarine and 2 teaspoons of sugar.
So, put 1 pat of the butter into one of the "hot water" containers and 1 teaspoon of sugar into the other "hot water" container. Likewise, put the same into the "cold water" containers. See what happens.
(You could also add 2 more containers where you add detergent to both the hot and cold water.)
Anyway, little kids usually don't really care about explanations of molecular energy levels and whatnot. And I think that if you do this experiment with her; she'll no doubt, figure out the idea of why hot water works better for washing dishes.
The folks here can surely provide the physics/chemistry of how it works....
jb
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