AIR AND WATER

IMPORTANT TERMS

Atmosphere – The atmosphere is the blanket of gases which surrounds Earth. It is held near the surface of the planet by Earth's gravitational attraction.

Humidity – Humidity is the amount of water vapour in the air. Water vapour is the gaseous state of water and is invisible. Humidity is high in rainy season and in coastal areas.

Air Pressure - Air pressure is the force exerted by air, whether compressed or unconfined on any surface in contact with it.

Gravity - Gravity is a natural phenomenon by which one thing attracts other things including stars, planets galaxies etc. Atmosphere is not needed for gravity.

Potable Water - Water fit for drinking by humans.

SMOG - is Smoke + Fog and is one of the worst air quality situations.

Pollution – Deterioration of air, water and soil by action of mankind like Industrial effluents, Machines emission and action of nature like mold, allergens and pollens.

LAYERS OF EARTH’S ATMOSPHERE

Exosphere – 500 to 10,000 Km. outer space

Thermosphere – 80 to 500 Km – Ionosphere - High temperature – Hot Layer/ Thickest – Space shuttle fly here

Mesosphere – 50 to 80 Km – Temperature drops with height – Cold Layer - Meteors burn up here.

Stratosphere – 15 to 50 Km – Ozone layer - Suitable for aircrafts

Troposphere – 0 to 15 Km – Good for living conditions  

 

KIND OF IMPURITIES AND PURIFICATION PROCESSES

Soluble Impurities – Evaporation, Distillation, 

Insoluble Impurities – Filtration, Sedimentation, Decantation

Cleaning agents - Insecticides, Pesticides, Chlorine

PURIFICATION PROCESSES

Boiling - Boiling is heating water above 100 degrees centigrade that kills germs present in water.

Evaporation - Evaporation is the process of a substance in liquid state changing to a gaseous state due to an increase in temperature or pressure.

Sedimentation - Sedimentation is the process in which insoluble impurities are allowed to settle down at the bottom of the container to form sediments.

Decantation - Decantation is a water purification process in which water is slowly poured off into another container after sedimentation.

Loading - The rate of sedimentation can be improved by adding special chemicals like alum. This process is called loading.

Chlorination - Adding chlorine to water to purify it is called chlorination. It is used to remove soluble impurities from water.

Filtration - Filtration is the method in which insoluble impurities can be removed by passing the impure water through a filter paper.

Distillation - Distillation is process to remove soluble impurities from water. It is the process of first converting a liquid into water vapour and then back to liquid, to purify it.

INTERESTING FACTS

Air contains 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% Carbon di oxide and 0.07% other gases

About 70% of Earth is covered with water and oceans contain 96% of the total water on Earth.

Water is the only matter that is found naturally in all three states (Solid, Liquid and Gas).

Nature provides us with the purest water, in the form of rains.

There are 6000 stars that are clearly visible to the naked eye above the Earth.