Year 10 Science · Unit 4 · Lesson 12
Challenge Worksheet
Learning Goals
Read the data
A life-cycle assessment (UK Environment Agency, 2011) estimated how many times each bag must be used to have a lower climate impact than a conventional plastic bag used once without secondary reuse. These estimates are for the bags and assumptions in that study.
| Bag | Uses needed |
|---|---|
| Paper bag | about 3 |
| Heavy plastic bag-for-life | about 4 |
| Non-woven polypropylene bag | about 11 |
| Cotton bag | about 131 |
1. Explain why the cotton bag needs so many more uses than the other bags.
2. This table presents climate impact only. Identify one other environmental impact that would change which bag looks best, and explain how.
Discuss the link
3. Discuss the link between human activity and microplastic pollution in the ocean. Include at least two human sources, the pathway each takes, the evidence that the source is human, and what is not yet known about the harm.
Evaluate the claim
4. "Modern waste management has nothing to learn from Aboriginal and Torres Strait Islander harvesting practices and Cultural protocols." Evaluate this claim using one named practice, one Cultural protocol, and one modern example of resource management.
Q1 · 2 marks: Cotton cultivation and bag manufacture have a relatively high production burden (1). Reusing the bag spreads that initial burden across more shopping trips, so many uses are needed to reach the stated comparison (1). The table is one study scenario, not a universal reuse threshold.
Q2 · 2 marks: For example, assess harm from escaped litter: a bag with a favourable climate result may still persist as litter or harm wildlife (1 identified impact + 1 explained effect). Accept another relevant impact, such as water demand or nutrient pollution, with a supported explanation. The study assessed several categories; this table presents only the climate comparison.
Q3 · 6 marks: Example response: Washing synthetic clothing can release fibres that pass through wastewater systems. Tyre wear creates particles that can be carried from roads by stormwater. Both pathways can reach coastal waters, where particles may be taken up by organisms. Manufactured polymers, fibre shapes and the connection to these waste streams support a human source. Detecting particles demonstrates exposure; it does not by itself establish the scale of ecological harm at every concentration. Effects depend on particle properties, exposure and the organism studied.
Marking guidance: two linked human sources (2); a credible pathway for each (2); evidence supporting human origin (1); a relevant limit on the harm inference (1). Accept equivalent accurate responses.
Q4 · 6 marks: Example response: The claim is too absolute. Baiame’s Ngunnhu on Ngemba Country shows detailed knowledge of river flow and fish movement in the design of fish traps. Responsibilities for particular traps and shared access are examples of resource governance, rather than unrestricted taking. Modern fisheries also use rules about access, timing and catch limits to manage a shared resource. These connections offer useful principles, but a modern system should be evaluated with local ecological evidence and developed with the relevant Traditional Custodians; a practice is not automatically transferable to every place.
Marking guidance: a reasoned judgement (1); named practice linked to ecological understanding (2); a Cultural protocol explained (1); a connected modern example (1); a supported limitation or qualification (1). Accept another locally accurate practice/protocol.
Source checks: Brewarrina National Heritage listing; CSIRO microplastics research; Environment Agency carrier-bag study (2011).