Matter in our Surroundings | Class 9 Science Notes
What is Matter?
Anything which occupies space and has mass is called matter.
Air and water, hydrogen and Oxygen, sugar and sand; silver and steel; copper and coal , iron and wood, ice and alcohol : milk and oil ; kerosene and petrol carbon dioxide and steam; carbon and sulphur, rocks and minerals, are all different kinds of matter, because all of them occupy space (that is, they have volume), and mass.
Matter can be defined as anything which has mass, occupies space and offers resistance is called matter.
Although we can not see but air is also a matter. Consider an example of deflated football and then after filling air, see that inflated football again. You'll observe that air has occupied space and has mass.
Now the things like friendship, love, affection, hatred, good manners, thoughts, ideas, taste and smell, etc, do not occupy space and do not have mass. So, from the point of view of chemistry, things like friendship, love, affection, hatred, good manners, thoughts, ideas, taste and smell are not considered 'matter'.
Similary energy like sound energy, light energy etc. are also non-matter.
Classification of Matter
Matter can be classified in a number of ways.
Ancient Indian philosophers said that all the matter padarth), living or non-living, was made up of five basic elements (panch tatva): air, earth, fire, sky and water (tayu, prithvi, agní, akash and jal).
Modern day scientists classify matter in two ways on the basis of its physical properties and on the basis of its chemical properties.
Physical Properties
On the basis of physical properties matter is classified as solids, liquids and gases.
Chemical Properties
And on the basis of chemical properties, matter is classified as elements, compounds and mixtures.
In this chapter, we will study the classification of matter on the basis of its physical properfies. The classification of matter on the basis of its chemical properties will be discussed in the next chapter.
Matter is made of Particles
All the matters around us is made of many tiny particles. The number of particles in each matter is very very large. And the size of these particles are so small that we can not see them even with high power microscope. But even without seeing them, there are evidance that matter is made of small particles.
Although such small particles are called atoms or molecules, but for the rest of this chapter we'll use the term “particles” only.
Evidence of Particles of Matter
Let us conduct 3 simple experiements which will prove that matter is made up of tiny particles which are constantly moving.
- Dissolving a Solid in a Liquid
- Mixing of two Gases
- Movement of Pollen Grains in Water
Before we start these experiments, let us understand the term Diffusion as it will be used in above mentioned experiments.
What is a Diffusion?
Diffusion is a physical process where molecules of a material move from an area of high concentration (where there are many molecules) to an area of low concentration (where there are fewer molecules).
Diffusion usually happens in a solution in gas or in a liquid.
| Diffusion Example | |
|---|---|
 |  |
 | A diagram of diffusion happening. The first diagram shows particles in a liquid. The second shows the same liquid a few seconds later after the particles have spread out |