Year 9 Science · Unit 3 · Lesson 11

Checkpoint 1, Energy Review

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Learning Goals

Apply knowledge from Lessons 1–10 to an unfamiliar scenario.
Identify which heat transfer methods and energy concepts are relevant in a real context.
Construct a multi-concept explanation using conduction, radiation, and energy conservation.

Warm Up

Odd one out

Circle the item that does not belong in each group. Then explain why it doesn't fit. Hint: think about the concept that links the other three.

#	Group	Your answer (odd one + reason)
1	Conduction Convection Radiation Inertia
2	Conduction Convection Radiation Expansion
3	Water Ethanol Lead Sand	(Hint: which has the highest specific heat capacity?)
4	Expansion joint Bimetallic strip Railway gap Parachute

Your Turn

Real-world context

On a cold morning in Canberra (−2 °C), a student fills a quality thermos flask with hot vegetable soup at 75 °C. Four hours later, the soup is still warm enough to drink at approximately 55 °C. The thermos has a double-walled vacuum layer between two stainless steel walls and a tight-fitting lid.

(a) The vacuum layer between the walls reduces heat loss by one method of heat transfer. Which method? Use a sentence starter: "The vacuum layer prevents… because…"

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(b) The inner steel wall of the thermos is often polished to a shiny finish. How does this help keep the soup hot? Use a sentence starter: "The shiny surface reduces… because…"

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(c) The soup cools from 75 °C to 55 °C over four hours. Using the law of conservation of energy, where does the thermal energy that left the soup go? Use a sentence starter: "The energy is not destroyed, instead it…"

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Wrap Up

In one sentence, what was the main idea of this checkpoint?