Appendix 2: Heat Transfer Application Challenge

Name:

Date:

Learning intention and key words

Learning intention: I can explain how heat energy moves from warmer objects to cooler objects and use evidence to support my explanation.

Remember: Heat moves from a warmer object or area to a cooler object or area.

Word bank

Conduction: Heat transfer through direct touching.

Convection: Heat transfer caused by the movement of a fluid, such as air or water.

Radiation: Heat transfer across space, without direct touching.

Conductor: A material that allows heat to pass through easily.

Insulator: A material that slows down heat transfer.

Part A: Identify the heat transfer

For each situation, tick one or more methods. Then explain how heat moves from warmer to cooler.

1. A metal saucepan sits on a hotplate.

Method:

Conduction

Convection

Radiation

Heat moves from the __________________________ to the __________________________ because

2. A wooden spoon is resting in the saucepan.

Method:

Conduction

Convection

Radiation

Heat moves from the __________________________ to the __________________________ because

3. A person is standing in sunlight.

Method:

Conduction

Convection

Radiation

Heat moves from the __________________________ to the __________________________ because

4. Warm air rises above a heater.

Method:

Conduction

Convection

Radiation

Heat moves from the __________________________ to the __________________________ because

5. A thermos keeps tea hot.

Method:

Conduction

Convection

Radiation

The thermos slows heat moving from the __________________________ to the __________________________ by

6. An insulated lunchbox keeps food cool.

Method:

Conduction

Convection

Radiation

The lunchbox slows heat moving from the __________________________ to the __________________________ by

7. An oven mitt protects a hand from a hot tray.

Method:

Conduction

Convection

Radiation

The mitt slows heat moving from the __________________________ to the __________________________ because it is an

8. A metal spoon becomes warm in hot water.

Method:

Conduction

Convection

Radiation

Heat moves from the __________________________ to the __________________________ because

Part B: CER Challenge

Use Claim, Evidence and Reasoning to explain your ideas.

Worked example: Why is a saucepan handle made from wood?

Claim: A wooden handle helps protect a person’s hand because wood is an insulator.

Evidence: The metal saucepan becomes hot on the hotplate, but the wooden handle transfers heat more slowly than metal.

Reasoning: Heat moves from the hotter saucepan towards the cooler handle and hand. Wood slows conduction, so less heat reaches the hand.

Write your own CER responses

9. Why does a thermos keep a drink hot?

Claim:

Evidence:

Reasoning:

10. How does an insulated lunchbox reduce heat transfer?

Claim:

Evidence:

Reasoning:

11. Choose an everyday heat-transfer example and explain it using CER.

Example: __________________________________________

Claim:

Evidence:

Reasoning:

Part C: Think deeper

12. Why are saucepan handles made from wood, silicone or plastic instead of metal?

13. Can more than one method of heat transfer occur in the same situation? Explain using evidence.

Teacher answer guide

Part A suggested answers:

1. Conduction, convection and radiation may all occur. The hotplate transfers heat to the metal saucepan by conduction. The saucepan and its contents may also warm by convection, and the hotplate gives off some radiation. Heat moves from the hotter hotplate to the cooler saucepan.

2. Conduction. Heat moves from the hot saucepan or water into the cooler wooden spoon by direct contact. Wood is a poor conductor, so it warms slowly.

3. Radiation. Energy travels from the Sun across space to the cooler person.

4. Convection. Air near the heater warms, becomes less dense and rises. Heat moves from the warmer air near the heater to cooler surrounding air.

5. More than one method can be reduced. The insulation slows conduction and convection, while the shiny inner surface can reduce radiation. Heat would otherwise move from the hot tea to the cooler surroundings.

6. More than one method can be reduced. The insulation slows conduction and convection, and may reduce radiation. Heat from the warmer surroundings moves more slowly into the cooler food.

7. Conduction is mainly reduced. The oven mitt is an insulator, so heat moves slowly from the hot tray towards the cooler hand.

8. Conduction. Heat moves from the hotter water into the cooler metal spoon through direct contact. Metal is a good conductor.

CER responses

Accept answers that include a clear claim, relevant evidence and reasoning about heat moving from warmer to cooler. Strong answers should mention insulation and explain that it slows conduction, convection and/or radiation.

Think deeper

12. Wood, silicone and plastic are insulators. They slow conduction from the hot saucepan to a person’s hand, unlike metal, which is a good conductor.

13. Yes. For example, in a saucepan, conduction transfers heat from the hotplate to the pan, convection moves heat through water or air, and radiation may transfer heat from the hotplate or pan. Credit other accurate examples supported by evidence.