Year 9 Science · Unit 3 · Lesson 9
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Learning Goals
Order the steps
Number the events from 1 to 6 to show the correct order. This chain explains why Sydney's coastal summer temperatures are more moderate than inland Broken Hill.
| Order | Event |
|---|---|
| The temperature difference between the cooler ocean and the hotter land drives a sea breeze toward the coast. | |
| The sun shines on both the ocean and the inland land surface with similar energy. | |
| The sea breeze lowers the coastal air temperature, moderating Sydney's climate compared to Broken Hill. | |
| The land has a much lower specific heat capacity than water, so it heats up far more quickly. | |
| The ocean absorbs the same solar energy but, because water has a very high specific heat capacity (4200 J/kg·°C), its temperature rises only slightly. | |
| Broken Hill, far from the ocean, has no sea breeze and swings to much higher temperatures in summer. |
Real-world context
A solar hot water system on a rooftop in Adelaide heats 200 litres (200 kg) of water from 18 °C to 60 °C during the day. The system also contains copper pipes that carry the water. Copper has a specific heat capacity of 385 J/kg·°C; water has a specific heat capacity of 4200 J/kg·°C.
(a) Without calculating, predict which would reach 60 °C faster if given the same energy input: the water or the copper pipes? Explain your prediction using specific heat capacity.
(b) Why is water chosen as the working fluid in this system rather than copper shavings or sand, even though those materials heat up faster?
(c) The system is used to supply hot water to a family of four. Explain why a large volume of water is better than a small volume for keeping the water hot overnight.
Wrap Up
In one sentence, what was the main idea of this lesson?