Year 9 Science · Unit 3 · Lesson 7

Heat and Temperature

Foundation Worksheet

Name

Date

Class

Learning Goals

Tell temperature, thermal energy and heat apart.
Identify conduction, convection and radiation in everyday situations.
Use data to describe how two objects reach thermal equilibrium.

Warm Up

Fill the gap

Choose the correct word from the word bank. Each word is used once. Two words will not be used.

equilibrium radiation average heat kelvin particles conduction joules temperature

is a measure of the kinetic energy of the in a substance. When particles move faster on average, the temperature rises. is the transfer of thermal energy from a hotter object to a cooler one. It is measured in . Temperature can be measured in degrees Celsius or in (K). When two objects in contact reach the same temperature, we say they have reached thermal .

Odd one out

Each group has one item that does not belong. Circle it, then explain why it does not fit.

#	Group	Odd one out, and why
1	Measured in °C or K · Average kinetic energy of the particles · Read from a thermometer · Total kinetic energy of all the particles
2	Cold flows from an ice block into your hand · Heat flows from a hotter object to a cooler one · Objects in contact end up at the same temperature · A cooling cup of tea loses thermal energy to the air
3	Conduction · Insulation · Convection · Radiation

1. Name the three methods of heat transfer. Which one can happen through empty space?

Recall 2 marks

Your Turn

Sort it: which method of heat transfer?

Write each example in the correct box. Each box gets two examples.

Sunlight warms a lizard basking on a rock Bare feet burn on a hot bitumen car park Warm air above a candle flame rises, carrying smoke upward An ice pack cools a sprained ankle Snow on a roof melts on a sunny day, although the air is below 0 °C Cool air from a wall air conditioner sinks to the floor

Conduction

Convection

Radiation

2. A backyard swimming pool is at 20 °C. A mug of coffee is at 80 °C. Which has more thermal energy? Explain why the answer might surprise people, using what you know about particles and mass.

Apply 2 marks

Go Deeper

Investigation: a hot egg in cold water

Sam lifted a hard-boiled egg out of the saucepan at 80 °C and dropped it into a bowl of tap water at 15 °C. A probe inside the egg and a thermometer in the bowl recorded both temperatures every 2 minutes.

Table 1. Temperatures of the egg and the water

Time (min)	Inside the egg (°C)	Water in the bowl (°C)
0	80	15
2	52	19
4	36	21
6	28	22
8	24	22
10	23	22
12	22	22

Source: sample class results.

3. Describe how the egg and the bowl of water changed. After how many minutes did both readings stop changing, and at what value? What is this state called?

Apply 3 marks

4. Sam wrote: “The coldness of the water flowed into the egg.” Rewrite the sentence so it is scientifically correct, and explain why the original is wrong.

Analyse 2 marks

Show What You Know

Scenario: a frosty morning at a bus stop

On a 1 °C morning in Armidale, a student waits for the school bus. She sits on a cold metal bench. The sun shines on her jacket. A breeze blows past her face. Inside her gloves she holds a warm heat pack.

5. Describe how heat moves in this scene. For each of the four situations, name the method of heat transfer and say which way the heat flows. Then explain why her gloves keep her hands warm.

Apply 5 marks