Earth's Atmosphere
Year 10 (IGCSE) 🌿 Materials & Environment Describe composition; explain climate change, acid rain and the ozone layer.
🌍 Composition of Air
| Gas | % by volume |
|---|---|
| Nitrogen (N₂) | ~78% |
| Oxygen (O₂) | ~21% |
| Argon (Ar) | ~1% |
| Carbon dioxide (CO₂) | ~0.04% |
| Water vapour + traces | Variable |
🌡️ Greenhouse Effect
Greenhouse gases absorb and re-emit infrared radiation from Earth's surface, warming the planet. Human activities intensify this.
N₂ and O₂ are NOT greenhouse gases — their symmetric structures don't absorb IR.
⚗️ Acid Rain & Ozone
Acid rain: SO₂ + NO₂ from fossil fuels dissolve in rain → H₂SO₄/HNO₃. pH 4–5. Harms ecosystems, corrodes limestone buildings.
Ozone depletion: CFCs release Cl• radicals → catalytically destroy O₃.
O₃ absorbs harmful UV-B protecting life on Earth.
Ozone depletion: CFCs release Cl• radicals → catalytically destroy O₃.
O₃ absorbs harmful UV-B protecting life on Earth.
Ready to test yourself? Click the Quiz tab above to practise questions on this topic!
Interactive Demonstration — Earth's Atmosphere
Explore the composition and evolution of Earth's atmosphere.
Click a segment to learn more about each gas.
🌍 Atmosphere Calculator
Calculate the mass of a gas in a given volume of air.