How can the full environmental impact of a product or process be assessed?
Use life cycle analysis to evaluate the sustainability and environmental impact of materials, products and chemical processes.
How life cycle analysis assesses the environmental impact of a product from raw-material extraction through manufacture, use and disposal, and how it informs sustainable resource management.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
You must explain what an LCA covers and use it to evaluate and compare the sustainability of materials and processes.
What life cycle analysis is
The point of an LCA is to avoid judging a product by one stage alone. A material that seems "green" in use may have a large impact during manufacture or disposal, and only a full-life view reveals the true cost.
The stages of a life cycle
- Raw-material extraction: mining or harvesting feedstocks; energy use, habitat disturbance, and whether the resource is renewable.
- Manufacture/processing: energy and water consumed, emissions and waste produced in making the product.
- Transport and distribution: fuel use and emissions in moving materials and products.
- Use: energy or resources consumed while the product is in service, and any emissions.
- Disposal or recycling: whether the product can be reused, recycled, or must go to landfill, and any pollution from disposal.
Using an LCA to compare materials
Sustainability and resource management
LCA supports sustainable resource management by highlighting where the biggest impacts lie, so designers can reduce energy use, choose renewable or recyclable materials, and design for reuse. It connects directly to green chemistry: improving atom economy and energy efficiency at the manufacturing stage lowers the overall life-cycle impact.
Exam-style practice questions
Practice questions written in the style of SACE Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
2024 SACE Stage 24 marksLimestone neoprene replaces some fossil-fuel feedstock with limestone, requires mining and high-temperature reactions, gives better insulation (thinner wetsuits), and lasts longer. With reference to one or more relevant science as a human endeavour concepts, discuss the impact on the environment of using limestone neoprene to make wetsuits.Show worked answer →
Discuss both benefits and costs across the life cycle for a balanced 4-mark response.
Benefits: replacing fossil-fuel feedstock with limestone reduces reliance on a non-renewable resource; better insulation means thinner wetsuits use less material; longer-lasting wetsuits are replaced less often, reducing waste.
Costs: mining limestone disturbs land and habitats; the high-temperature reactions require large energy inputs, which (if from fossil fuels) generate CO2 emissions.
Conclusion linked to a SHE concept (such as application and influence, or development): the manufacturers claim of lower environmental impact must be weighed against the mining and energy costs over the whole life cycle. Marks for at least two benefits, at least one cost, and a reasoned overall judgement.
2022 SACE Stage 22 marksComposite materials consist of synthetic polymers embedded with carbon fibre. Explain one difficulty with recycling composite materials.Show worked answer →
Composites combine two different materials that are bonded together.
The polymer matrix and the carbon-fibre reinforcement are tightly combined and cannot easily be separated back into their individual components.
Because the materials cannot be separated, they cannot be processed/reprocessed individually (for example the polymer cannot simply be melted and reused), making recycling difficult and costly. One mark for the materials being difficult to separate, one for why this prevents normal recycling.
2023 SACE Stage 24 marksTransparent wood is made from fast-growing balsa, is biodegradable, shatterproof, less dense than glass, and can be cut with existing equipment. Explain how the innovation of transparent wood is an example of science as a human endeavour.Show worked answer →
Connect the features in the passage to science as a human endeavour (SHE) ideas for 4 marks.
Development and innovation: scientists applied knowledge of cellulose and polymers to design a new material with deliberately improved properties.
Application and benefit to society: it provides a safer (shatterproof), lighter, biodegradable alternative to glass for windows, with practical benefits in construction.
Sustainability: it uses a fast-growing renewable plantation resource (balsa) and is biodegradable, reducing environmental impact.
Influence/uptake: it can be cut using existing industrial equipment, so it can be adopted readily by industry. Marks for several well-explained SHE points tied to evidence from the passage.