Year 9 Science · Unit 2 · Lesson 18
Foundation Worksheet
Learning Goals
True or False? Fix the false ones
Circle T or F for each statement. If the statement is false, rewrite it correctly on the line below.
All bioplastics are biodegradable in all conditions, including home compost bins and the ocean.
Correct it:
A paper bag takes approximately 1 month to biodegrade under normal conditions.
Correct it:
Polyethylene bags are not biodegradable because they are made from natural plant materials that microorganisms cannot digest.
Correct it:
Life Cycle Assessment (LCA) considers the full environmental impact of a product from raw material extraction through manufacturing, use, and disposal.
Correct it:
A cotton bag becomes environmentally better than a plastic bag after just one use.
Correct it:
Odd one out
Circle the item that does not belong in each group. Then explain why it doesn't fit on the right.
| # | Group | Your answer (odd one + reason) |
|---|---|---|
| 1 | PLA Starch-based foam Cellulose film Polyethylene | |
| 2 | 1 month 5 months 5 years 450 years | |
| 3 | Reduce Reuse Recycle Incinerate |
1. Define "biodegradable" and explain why synthetic polymers like polyethylene are NOT biodegradable. Include the term "C–C backbone" in your answer.
2. Explain why UV photodegradation of plastic does NOT solve the problem of plastic pollution, even though the plastic breaks into smaller and smaller pieces over time.
Wrap Up
In one sentence, what was the main idea of this lesson?