What are the characteristics of solids?
(i) Solids have a definite shape.
Because the particles of a solid are very close to each other, they have a definite shape. For example, solid objects like an iron nail, a book, or a wooden table.
(ii) Solids have distinct boundaries.
As solid objects have a definite shape, they have well-defined boundaries.
(iii) Solids have a fixed volume.
A body, with a fixed shape and a distinct boundary, has a fixed volume as well. This means the matter in these solid objects occupies a fixed amount of space.
(iv) Solids have negligible compressibility.
The tightly packed particles of solids make them rigid. That is why they retain their shape even when subjected to an external force. They may break under force, but they retain their shape.
For example, when a rubber band is pulled, it expands but it gets back to the original shape after the force is released. But at a certain point, it will break.
What are the characteristics of liquids?
(i) Liquids do not have a fixed shape.
Liquids usually flow and they also take the shape of the container they are poured into. This means they are not rigid, but fluid.
(ii) Liquids have a fixed volume.
As liquids occupy a fixed space, they have a fixed volume.
(iii) Solids, liquids and gases dissolve in liquids.
For example,
Solid crystals of copper sulphate will dissolve in water. Drops of ink diffuse in water.
Gases like oxygen and carbon dioxide diffuse and dissolve in water.
What are the characteristics of gases?
(i) Gases have neither shape nor volume.
Particles of gas are far apart from each other. They spread over a large area and, the particles move randomly.
(ii) Gases are highly compressible.
Compared to solids and liquids, gases have much higher compressibility. Under high pressure, a large volume of gas can be compressed into a small cylinder.
What is the Interchange of the states of matter?
When solids change into liquids, liquids into gases and vice versa, it is called the Interchange of the states of matter. This change happens when the particles of matter are spaced apart or compressed.
Interchange of states of matter