OpenOlympiad
Concept 1 of 8Foundation
Video

Air — the invisible ocean

Earth is wrapped in a layer of gases called the atmosphere. We live at the bottom of this ocean of air.

Air is NOT a single gas — it's a mixture:

  • ~78% Nitrogen (N₂)
  • ~21% Oxygen (O₂)
  • ~1% Argon, carbon dioxide, water vapour, dust, pollutants

Plants make oxygen (photosynthesis). Animals and burning use oxygen and release CO₂.

Example
Blow up a balloon — it's full of air (mostly nitrogen). Light a match inside? Flame uses up the ~21% oxygen.
N₂ 78%O₂ 21%Other 1%
💡 Tip:Nitrogen is plentiful but mostly inert. It's the OXYGEN in air that keeps us alive and fires burning.
Prefer a video? Open YouTube search for “composition of air class 6

🎯 Try it!

5 questions to check what you just read.

0 / 5
  1. Q1.Approx % of nitrogen in air:
  2. Q2.Approx % of oxygen in air:
  3. Q3.Which gas do we use to live?
  4. Q4.Air is:
  5. Q5.Plants release ___ into the air during photosynthesis: