Year 9 Science · Unit 3 · Lesson 12
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Learning Goals
1. The lesson says that wind is driven by the Sun. Explain what this means, and why it makes wind a renewable source.
2. Complete the table. Write the energy transformation chain for each power station, naming the form of energy at each stage. Then name the main form of waste energy.
| Power station | Energy transformation chain | Main waste energy |
|---|---|---|
| Wind farm in South Australia | ||
| Hydroelectric station below a dam in Tasmania | ||
| Sugar mill in Queensland that burns crushed cane waste to make electricity | ||
| Geothermal plant using hot rocks deep underground |
Cause and effect: why hydro is stored solar energy
Complete the chain. Each box is caused by the one before it.
3. Use your chain to explain why hydroelectricity is renewable, and name one weather condition that could reduce the electricity a hydro scheme can make.
Data: a rooftop solar system on a sunny day
A family in Toowoomba recorded the power output of their rooftop solar system every two hours on a clear day in October.
| Time | Power output (kW) |
|---|---|
| 6 am | 0 |
| 8 am | 1.2 |
| 10 am | 3.4 |
| 12 noon | 4.2 |
| 2 pm | 3.4 |
| 4 pm | 1.2 |
| 6 pm | 0 |
Source: sample data.
4. Draw a line graph of the solar system’s output across the day.
5. (a) Estimate the energy the panels made that day. Treat each reading from 8 am to 4 pm as the average power for the two hours around it, and use E = P × t. (b) The family uses 20 kWh a day, and most of it between 5 pm and 10 pm. Explain why the solar system alone cannot power the house, even though it makes more energy than the house uses.
(a) Energy made kWh
Evidence check: “Australia should invest heavily in renewable energy.”
A. Australia receives more solar radiation per square metre than any other continent.
B. Solar panels and wind turbines are now the cheapest sources of new electricity in most of the world.
C. Wind turbines are much taller than most houses.
D. Battery storage will keep getting cheaper over the next ten years.
E. We should protect the jobs of people in coal-mining towns.
F. Solar panels make no electricity at night.
6. The lesson says good scientific thinking separates facts, predictions and values, and checks whether a true statement really supports a claim. Label each statement A to F as a fact, a prediction or a value. Then use the relevant statements, and your own knowledge of how solar and wind work, to write a short evaluation of the claim.