AQA A-Level Environmental Science 3.2 The physical environment: a complete overview of atmosphere, water, minerals and soil

What module 3.2 actually demands

The physical environment covers the non-living systems that make life possible and that human activity depends on. Module 3.2 runs from the atmosphere and its role in climate, through the hydrosphere and the water cycle, the formation and extraction of mineral resources, the biogeochemical cycles of phosphorus and sulfur, and the composition and conservation of soils. The examiners test recall of structures and processes alongside the application of these ideas to resource management and environmental impact.

This guide walks through all five topics of the module, then sets out the exam patterns AQA repeats. Each topic has a matching dot-point page with practice questions; this overview ties them together.

The atmosphere and the hydrosphere

The atmosphere is about 78 percent nitrogen and 21 percent oxygen, layered into the troposphere, stratosphere, mesosphere and thermosphere. The natural greenhouse effect keeps the Earth warm, the atmosphere redistributes heat to drive climate, and the ozone layer absorbs ultraviolet radiation. You must keep the greenhouse effect and ozone depletion clearly separate.

The hydrosphere holds the Earth's water, but only a tiny fraction is accessible fresh water. The water cycle moves water by evaporation, transpiration, condensation, precipitation, infiltration and runoff, and the oceans store and transport heat that regulates climate.

Minerals, cycles and soils

Mineral resources form by geological processes that concentrate minerals into ores. You must distinguish resources from reserves, describe surface and deep mining, and evaluate the environmental impacts of mining and how they are reduced.

Biogeochemical cycles describe how elements move between stores by fluxes. The phosphorus cycle has no gas phase and is slow; the sulfur cycle has a gas phase and is linked to acid rain. Decomposers are central to both.

Soils are mixtures of minerals, organic matter, water, air and organisms that form slowly into horizons. Fertility depends on texture, structure, nutrients and pH, and the slow-forming soil is easily degraded by erosion, salinisation and nutrient loss, so conservation matters.

How module 3.2 is examined

A typical AQA profile for The physical environment:

• Definitions and recall. Atmospheric composition and layers, water-cycle processes, ore formation, and soil components.
• Applied questions. Explaining how a human activity affects climate, water supply, a biogeochemical cycle, or soil quality.
• Evaluation. Weighing the environmental impacts of mining or the benefits of soil conservation methods.
• Extended answers. Distinguishing the natural and enhanced greenhouse effects, or explaining why fresh water and fertile soil are limited resources.

Check your knowledge

A mix of recall and applied questions covering module 3.2. Attempt them under timed conditions, then check against the solutions.

1. State the two most abundant gases in dry air and their approximate percentages. (2 marks)
2. Explain the difference between the natural and the enhanced greenhouse effect. (2 marks)
3. State approximately what percentage of the Earth's water is salt water. (1 mark)
4. Name three processes of the water cycle. (3 marks)
5. Explain the difference between a mineral resource and a reserve. (2 marks)
6. Explain why the phosphorus cycle has no significant gas phase. (2 marks)
7. Name the five main components of soil. (2 marks)
8. Describe two methods of reducing soil erosion. (2 marks)