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“Yesterday is history. Tomorrow is a mystery. Today is a gift. That’s why we call it ‘The Present’.” – Eleanor Roosevelt

Composition of Air

Gases in the Air


What is air?

Air is a mixture of gases.


Can you feel air? Yes

When the air is moving we can feel it. Moving air is called wind.

E.g. – When you run or cycle you can feel the air is blowing on your face and body.


Can you hear air? Yes.

E.g. – On a windy day as the air rushes through the trees we can hear it.


Can you see air? No.


Does air have a colour? No.


Can you taste air? No.


Can you smell air? No. Clean air does not have a smell.



What are the main features or characteristics of air?


  • Air is invisible. (Air cannot be seen)
  • Air is colourless. (Air doesn’t have a colour)
  • Air is tasteless. (Air doesn’t have a taste)
  • Air is Odourless or scent free. (Air doesn’t have a smell)
  • Air can escape through the smallest hole of the container which it is kept.


What does air include?


  • Gases

E.g. –       Nitrogen 78%

               Oxygen 21%

               Carbon dioxide 0.03%

               Noble gases 0.97% (Helium, Argon, Krypton)


  • Water Vapour (The amount changes)


  • Tinny winy particles of dust (The amount changes)



Are the gases in the air important for us?

Yes, the gases in the air are important for us in many ways.




Nitrogen Too much of oxygen is dangerous for humans. Nitrogen reduces the strength or flavour of oxygen in the air.
  1. Used by humans and animals to breath.
  2. Used by humans and animals to turn the food we eat into energy.
  3. Used by fires to burn.
Carbon dioxide
  1. Used by plants to breathe.
  2. Used by plants to make food.
  1. Used in filling balloons.
  1. Used in filling light bulbs.
  2. Used in welding (join two pieces of metal together by heating).
  1. Used in powerful bulbs that shine through fog (thick mist).