Matter In Our Surroundings CBSE Class 9

What is matter?

Anything which occupies space, has mass and offers resistance to force applied on it is called matter.

Example: book, table, water, stone. But love, sad are not matter.

Theory of Molecular Structure of Matter or Characteristics of Particulate Nature of Matter:

1. Matter consists of extremely small particles which can exist independently, called molecule.

2. The molecules of matter are in continuous motion and they have kinetic energy.

3. This kinetic energy is directly proportional to temperature.

4. For solid, this kinetic energy is least and for gas is maximum.

5. The space between the molecules is called intermolecular space and it is least for solid and maximum for gas.

6. The attraction force between the molecules is called intermolecular force and it is least for gas and maximum for solid.

7. The intermolecular force is inversely proportional to intermolecular space.

What is volume?

The amount of space occupied by a body , is called its volume.

What is mass?

The amount of matter present in a body is called mass.

Mass measure in physical balance.

What is material?

The term is used to describe a particular kind of matter, is called material.

Example: wood is material.

What is homogeneous material?

A material which has the same composition and same properties throughout, is called homogeneous material.

What is heterogeneous material?

A material which has different compositions and different properties in different parts is called a heterogeneous material.

What is substance?

A homogeneous material which is made of only one kind of atoms or molecules is called a substance.

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