Translate 热胀冷缩的原理 into English?

[elina]

I’d translate: the theory of expanding when heat and shrinking when cold, but I know it’s just ugly English, not natural, so I’d like to hear how the others do it. Thanks in advance.

[roddy]

Principle of thermal expansion?

[elina]

Thanks, I have done my job with your help here:

http://9822629.s31.sqnet.cn/book.asp?id=4225