We can change the physical states of matter by heating and cooling them.
Liquids differ from gases because particles are closely packed in liquids but loosely packed in gases. Liquids have fix volume but gases do not.
In solids, particles have an orderly arrangement and are tightly packed together. While in liquids, the particles are present very close to one another but they are not regularly arranged.
On cooling a solid decreases its motion of particles. Decrease in motion of particles allows them to bring close together due to force of attraction.
1. Freezing: To preserve food items like fruits, vegetables, meat, dairy products etc. Make ice cubes to chill our drinks.
2. Boiling: To cook food items like rice, pasta, vegetables and meat. Produce steam to generate electricity.
3. Evaporation:To dry our clothes, hair and wet items.
4. Condensation: In air conditioning systems.
5. Melting :To cook food items like chocolate, butter and cheese. To shape and mold metals.
Solids have fixed shape and volume because their particles are held together by strong inter molecular forces. They do not move freely that is why they have fix shape and volume.
Solids do not flow like liquids and gases because their particles are tightly packed together and have strong bonds that keep them in fixed positions. Whereas liquids and gases have particles that can move past each other, allowing them to flow and change shape easily.
The movement of particles from an area where they are more to an area where they are less is called diffusion of particles.
For example, movement of body spray particles in a room.
When a solid changes into a gas without becoming a liquid first. This process is called sublimation.
For example, conversion of solid carbon dioxide dry ice into gaseous carbon dioxide.