Air Around Us
Properties of Air
Have you seen kites flying in the sky? You may have also seen flags swirling in the sky? What makes these objects move?
They move because of the presence of air. The objects move along with the movement of air.
If air exists, then it should occupy space. Let us perform an activity to show that air occupies space.
Take a large, open bowl or a bucket and fill it with water. Now, invert an empty narrow bottle (may be a soft drink bottle) into the water. Does water enter the narrow-mouthed bottle easily?
Although the bottle looks empty, it is not actually so. Air occupies the space inside the bottle and therefore does not allow the water to enter it easily. Thus, all regions although may look empty, do contain some air. The layer of air that surrounds the Earth is called atmosphere.
Properties of oxygen
When a burning matchstick is brought near kerosene gas stove (with its knob turned on), it will be observed that the gas coming out of the stove, i.e. LPG, starts burning instantly to produce heat and light. Hence, LPG is a fuel.
Similarly, there are fuels such as wood, coal, charcoal, petrol, diesel, etc. that are used for various purposes at home, in industry, and for running vehicles. These fuels burn to produce large amounts of heat. Thus, burning or combustion is a chemical process in which substances react with oxygen to produce heat.
Fuel + Oxygen (from air) → Carbon dioxide + Water vapour + Heat
Do you know that there ar...
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