STATES OF MATTER
Matter around us exists in three different states– solid, liquid and gas, dependent on the characteristics of the particles of matter.
1. SOLID STATE – Solids have a definite shape, distinct boundaries and fixed volumes, that is, have negligible compressibility.
- Solids may break under force but it is difficult to change their shape, so they are rigid.
Examples, a pen, a book, a needle and a piece of wooden stick, a granule of sugar.
- There are objects that are solid in state but seems do not follow the above rule but actually they do
- A rubber band changes shape under force and regains the same shape when the force is removed. If excessive force is applied, it breaks.
- A sponge has minute holes, in which air is trapped, when we press it, the air is expelled out and we are able to compress it.
2. LIQUID STATE – liquids have no fixed shape but have a fixed volume.
- They take up the shape of the container in which they are kept.
- Liquids flow and change shape, so they are not rigid but can be called fluid.
- Solids, liquids and gases can diffuse into liquids (e.g. oxygen and carbon dioxide dissolves in water, which helps the survival of aquatic animals and plants)
- The rate of diffusion of liquids is higher than that of solids.
- This is because in the liquid state, particles move freely and have greater space between each other as compared to particles in the solid state.
3. GASEOUS STATE – gases are highly compressible as compared to solids and liquids
- Due to its high compressibility, large volumes of a gas can be compressed into a small cylinder and transported easily
- Examples: liquefied petroleum gas (LPG) cylinder, Compressed natural gas (CNG) fuel tanks
- Due to high speed of particles and large space between them, gases show the property of diffusing very fast into other gases.
- Rate of diffusion is much faster than solids and liquids
- In the gaseous state, the particles move about randomly at high speed.
- Due to this random movement, they exert pressure which is the force exerted by each gas particles per unit area on the walls of the container.