Matter

Volume  of matter

The space occupied by a substance is called its volume.

solids

  Solids have definite shape and occupy definite space. Your , table, chair, a plant or an animal are solids . Some solids can be poured e.g. sugar, salt and flour are all solids in this case. Each particie of solid keeps the same shape and occupies the same space

Liquids

 Liquids do not have any shape. Instead they take the shape of the information container. However, liquids can be poured occupy definite space. Water, milk 

Gases

Gases do not have any shape and do not occupy definite space e.g. air. 

Arrangement of Particles  in matter

 In each state, the arrangement of particles of matter is very different. That is why, all states of matter have different properties. In the following paragraphs, you will see how the different arrangements of parties give different properties to solids, liquids, You know that anything which occupies space and has mass, called matter. You are also of the three states of matter. solids, liquids and gases of objects. You and your class fellows are sitting on chairs in your classroom. You are reading your books. Your bags and notebooks are kept in desks. Your teacher is writing on the blackboard. There are different kinds of pictures on the wall. Some indoor plants are placed at the corner of the room. There is a glass water at your teacher's table. All these objects and so many others are different forms of matter. Even the air around you is a form of matter. The space occupied by substance is cailed its volume.

 Arrangement of particles in a liquid 

The particles in a liquid are apart from each other, but are still held together. So the liquids occupy a definite space and cannot be compresed. Unlike solids, the particles of a liquid are not fixed in regular posiions id they move short distances. That is why, a liquid has no definite shape. Particles in a Gas characteristics: They are far apart. They are arranged in irregular way. They move quickly in all directions. There are very weak forces of attractions among them. 

Arrangement of particles in a gas

 Ice melts into water

 Robert Hooke was an English scientist. In .1678, he explained the properties of different states of matter. He was the first who told that when we heat matter, it expands. He also discovered that air is made up of particles separated from each other by large spaces.

 Freezing of liquid

 Change of a liquid into a solid Its particles loose energy. They start moving slowly. The particles lose more and more energy and come closer to each other. Then they get closely packed and are in fixed positions. You know ice cream is made by freezing milk. Air is the most important part in ice cream as it is needed to keep the ice cream soft.

 Boiling: 

Change of a liquid into a gas What happens when you heata liquid? Its particles gain energy. They start moving faster. You know which state of matter has this type of particles arrangement. Yes! the liquid has changed into a solid. This process is called freezing.

 What happens when you continue heating? 

The particles become free from one another. They move quickly in all directions. Now they are irregularly arranged and are far apart. You know these are the characteristics of the particles of a gas. Yes! the liquid has changed into gas state. The process by which a liquid gets heat and changes to gas is called boiling. Many liquids can be changed into gases when we boil them with different amounts of heat. You know that tap water contains many disease causing microorganisms. Boiling water is the best way of killing all microorganisms present in water. 

Evaporation:

 All particles of a liquid do not move with the same speed. Some particles have more energy than the others. The high energy particles come to the surface of liquid and then escape from there. They move into air, as a gas. Evaporation is the process by which a liquid changes into gas at a temperature which is below the temperature at which it boils. If you leave water in a pan, it evaporates until no water is left there. 

 Surface of liquid

 Low energy particles remain as liquid High energy particles escape from surface Evaporation occurs only at the surface of liquid while boiling occurs in the whole liquid. Evaporation occurs at all temperatures but if we provide heat to a liquid, its evaporation becomes fast. 

Condensation: 

 Condensation is the process by which a gas (vapours) changes into a liquid, by the effect of cooling. If we cool water vapours (a gas), they are converted into water (a liquid) again. This is an example of condensation. From what small drops of water on the outer walls of cold water bottle come. There are many water vapours in air (in the form of moisture). When these vapours touch the cold walls of bottle, they change into liquid water. This water makes small drops on the walls of bottle. We use natural gas in our homes in its gas state. When we take it to other countries by ocean, it is converted to liquid state (called liquid natural gas: LNG) to save space.