do solid expand ?and what are the examples of solid
Answers
Answer:
Yes,on heating solid expands.
Answer:
Just about every (but not all) solids expand with an increase in temperature. Why? Before going to the answer, let's look at a common model of a solid - the ball and spring model.
In this model, solid matter is made of tiny little balls connected by springs. The balls would be the atoms that make up the material and the springs represent the interactions each atom has with it's neighbors. These tiny balls don't just sit there, they oscillate around just a little bit. But clearly matter isn't made of tiny little springs, right? Right. So, even though this model is not exactly true, it's still very useful. With this ball and spring model, we can explain:
The contact force with some solid isn't constant. The more something pushes against material, the greater this constant force becomes.
When you pull on a metal, it stretches.
The speed of sound is different in different materials.
This is why we use this model - because it's useful in some situations.
Simple Springs
Let's look at a case where this simple ball and spring model doesn't quite work. If I have molecular hydrogen gas, I could represent that as two balls connected by a spring and each ball would be a hydrogen atom (molecular hydrogen is H2).
As these two balls move closer together, the interatomic spring pushes them apart. And then as they move further away, the interatomic spring pulls them back together. The result is a nice oscillating molecule. As with any oscillation, we can describe this in terms of energy. For the system consisting of the two hydrogen atoms and the connecting spring, there is a constant total energy (since there is no work done on the system). This means that the sum kinetic energy of the two balls plus the spring potential energy is constant. It's nice to represent this as a plot of the potential energy like this: