Study Notes
Air is a mixture of gases that forms a thick blanket around the Earth, known as the atmosphere. It mainly consists of oxygen and nitrogen, with smaller amounts of carbon dioxide, noble gases, water vapour, dust particles, and other trace gases.
- Air — mixture of gases on Earth. Example: The air we breathe contains oxygen and nitrogen.
- Atmosphere — thick blanket of air surrounding Earth's surface. Example: The atmosphere protects us from harmful solar radiation.
- Wind — moving air. Example: Wind can be felt as a breeze on a windy day.
- Air Pollution — harmful substances in the atmosphere. Example: Smoke from factories contributes to air pollution.
- Greenhouse Effect — warming of Earth due to trapped heat. Example: Carbon dioxide increases the greenhouse effect.
- Global Warming — increase in Earth's average temperature. Example: Melting ice caps are a result of global warming.
- Ozone Layer Depletion — thinning of the ozone layer. Example: CFCs contribute to ozone layer depletion.
- Acid Rain — rain containing harmful acids. Example: Acid rain can damage forests and lakes.
Exam Tips
Key Definitions to Remember
- Air: Mixture of gases on Earth.
- Atmosphere: Thick blanket of air surrounding Earth.
- Air Pollution: Harmful substances in the atmosphere.
Common Confusions
- Confusing air with pure oxygen.
- Thinking air pollution only comes from human activities.
Typical Exam Questions
- What is the main composition of air? Oxygen and nitrogen are the main components.
- How does air pollution affect the environment? It leads to global warming, acid rain, and ozone layer depletion.
- What is the greenhouse effect? It is the warming of Earth due to trapped heat from gases.
What Examiners Usually Test
- Understanding of the composition of air.
- Effects and causes of air pollution.