Why do atoms in a solid act like hard balls?

[TaraaaK]

Homework Statement

Why can we assume that atoms in a solid material act like hard balls?

The Attempt at a Solution

because they are tightly packed together when in a solid state[/B]

 

[PietKuip]

It is not really true, many solids have structures that are not like those of close-packed spheres.

It is approximately true because of the Pauli exclusion principle. But I do not know if that answer fits with what you learned in your course.

 

[davenn]

Homework Statement

Why can we assume that atoms in a solid material act like hard balls?

The Attempt at a Solution

because they are tightly packed together when in a solid state[/B]

I will counter that with
Why do YOU think the atoms in a liquid or gas act any differently ?

Do you think there is any difference between individual atoms of H and O in liquid water
compared with those in solid water ... eg. ice ?Dave