Definition Of Solids
Objects with definite size and shape are known as solids.
More About Solids:
The size and shape of the solid do not change by itself.
The molecules are held close together in a solid body.
The molecules inside the solid exert large attractive forces on each other.
The force of attraction is so great that each molecule is allotted a definite place, in the body.
The molecules inside the solids cannot move by themselves.
The molecules cannot leave the position allotted for them. They can only vibrate about their mean position.
The average distance between the molecules is very small (in the order of 10-10m).
The solids cannot be compressed because there is no space between the molecules to get compressed.
Example: Consider following piece of stone.
It cannot be compressed, because there is hardly any piece of space between molecules.
It has a definite shape and size because the force of attraction between the molecules is very high.
Worked Example:
State which of the following describes a solid.
A. Particles move about freely at high speed.
B. No Fixed shape and volume.
C. Particles vibrate and cannot change positions.
D. Fixed volume but no fixed shape.
Correct answer is C
Solution:
Step 1:In gases particles move about freely at high speed, but the same is not possible in solids
Step 2: Gases will not have any fixed shape or volume.
Step 3: In solids the molecules can vibrate about their mean position but cannot change their respective position
Step 4: Liquids have fixed volume but they will not have particular shape