Matter around us — Important Questions

Diffusion

Diffusion is the process where particles of one substance spread and mix with particles of another substance. This happens because particles of matter are in continuous motion and move from areas of higher concentration to lower concentration. Examples include the spreading of perfume in a room, ink mixing with water, or the smell of food spreading in the kitchen. Compression is reducing volume, expansion is increasing volume, and evaporation is the change from liquid to gas state.

Gases in gases

Gases diffuse fastest because gas particles move at very high speeds and have large spaces between them, allowing easy movement. When you light an incense stick, the smell spreads quickly throughout the room because gas particles (scent vapor) diffuse rapidly in air. Liquids diffuse slower than gases because their particles move slower and are closer together. Solids diffuse slowest because their particles have limited movement and are tightly packed.

Compressed Natural Gas

CNG stands for Compressed Natural Gas. It is natural gas that has been compressed to very high pressure to reduce its volume, making it easier to store and transport in vehicles. This is a practical example of gas compression - a large volume of natural gas is compressed into small, portable cylinders that can be fitted in cars and buses. The compression is possible because gases have large spaces between particles that can be reduced under pressure.

Matter is made up of tiny particles

When a few crystals of potassium permanganate color a large amount of water, it proves that matter is made up of tiny particles. The crystals contain millions of tiny purple-colored particles that spread throughout the water, giving it color. Even after diluting the solution many times, some color remains, showing how small these particles are. This experiment demonstrates the particulate nature of matter - both the solid crystals and liquid water are made of tiny particles.