Summary and Exam Tips for Pollution and Resources
Pollution and Resources is a subtopic of Earth and Space, which falls under the subject Science in the Cambridge Lower Secondary curriculum. This unit explores the composition of air and the distinction between renewable and non-renewable resources. Air is a mixture of gases, primarily oxygen and nitrogen, with traces of carbon dioxide, noble gases, water vapor, and dust particles. The atmosphere, a thick blanket of air, surrounds the Earth, and moving air is referred to as wind. Air pollution occurs when harmful gases, liquids, or solids are present in the atmosphere at levels that can harm humans, organisms, or materials, leading to effects such as the greenhouse effect, global warming, ozone layer depletion, and acid rain.
The unit also covers renewable and non-renewable energy sources. Renewable energy, which can be replenished, includes biofuels, wind, hydroelectric, tidal, geothermal, and solar power. Non-renewable energy, such as fossil fuels and nuclear fuel, cannot be replenished and is used for large-scale electricity production due to its high energy output per kilogram. The environmental impact, cost, reliability, and scale of these energy sources vary, with renewable sources generally having a positive environmental impact but higher costs and varying reliability.
Exam Tips
- Understand the Composition of Air: Focus on the primary components of air and the effects of air pollution, such as global warming and acid rain.
- Differentiate Energy Sources: Be clear on the differences between renewable and non-renewable energy sources, including examples and characteristics.
- Environmental Impact: Remember the environmental impacts of different energy sources, noting that renewable sources generally have positive impacts.
- Reliability and Cost: Be prepared to discuss the reliability and cost implications of various energy sources, particularly how they affect their usage on different scales.
- Practical Applications: Consider how electricity is generated from different energy sources and the practical implications of their renewability and environmental impact.
