Name: Nim
Status: student
Grade: 9-12
Country: Australia
Date: Summer 2011
Question:
I understand that for solids, surface energy usually decreases with the increase of temperature. But why is this? Metals do not behave in this manner. Why?
Replies:
You have addressed a very difficult experimental question. Measurement of
surface tension (I prefer the equivalent definition "surface energy"). This
is the amount of energy required to extend the energy required to expand the
surface of a substance per unit area, but this only a matter of
interpretation. Numerically the "numbers" are the same. This means that you
have to consider the composition of the "surface" of the substance being
measured. The challenge is to be sure what the composition of the surface
really is!! On top of this you are asking how this changes with
temperature!! If you really "understand that surface energy increases with
the increase of temperature." You are to be congratulated -- but I do not
think that will hold up in general. This is not a "put down". You have
addressed a very difficult experimental question. I do not think there is a
general answer to your question. It is better to admit ignorance of the
answer than to propose bogus answers.
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