PARTICULATE NATURE OF MATTER

CONTENT

1. The Definition of Matter
2. Structure of Matter
3. Evidence of the Particle Nature of Matter
4. Experimental Evidence of the Particle Nature of Matter
5. Explanation of Brownian Motion
6. Simple Atomic Structure
7. The Nature and Size of Molecules

The Definition of Matter

Matter is anything that has weight and occupies space. Every object or substance is made up of matter. Many of the properties and behavior of substances can best be explained by assuming that all substances are composed of small particles called molecules. The assumption that matter is made up of tiny particles (molecules) which are in constant motion is known as the “molecular theory of matter.”

Structure of Matter

Evidence of the Particle Nature of Matter

(i) Many substances in solid form can easily be crushed to powder form e.g. piece of chalk, lump of clay, charcoal and piece of stone.

(ii) A dry stick or dry wood is easily broken into smaller bits

(iii) Solubility – if you drop a cube of sugar into a cup of water and turn the water, the sugar “disappears”.