Effective insulation | Physics | Quizalize & Oak National Academy

Starter quiz

Match the following temperatures to their description.

5600°C

⇔

the surface of the Sun ✓

100°C

⇔

boiling point of water ✓

0°C

⇔

freezing point of water ✓

-183°C

⇔

boiling point of oxygen ✓

20°C

⇔

typical room temperature ✓
Which of the following materials is the best thermal insulator?

copper

steel

plastic ✓

iron

aluminium
Why is copper a good choice for the base of a frying pan?

It is a good thermal conductor and transfers energy quickly. ✓

It is an insulator and so saves energy.

It has a high melting point. ✓

It does not get hot when heated and so the pan can be handled safely.

It conducts electricity.
Wool is used in some clothing. Why is wool good at keeping a person warm?

Wool produces heat when in contact with the body.

Wool traps air which is a good thermal insulator. ✓

Wool is a good thermal conductor and lets the heat in.

Wool is soft, this makes it comfortable to wear.

Wool has holes that lets the air travel freely through it.
Which of the following particles make metals good thermal conductors?

free protons

free neutrons

free ions

free electrons ✓

free molecules
What is the condition needed for two objects to be in thermal equilibrium?

One of the objects must be hotter than the other.

One of the objects must be colder than the other.

The two objects must be metals.

The two objects must be thermal conductors.

The objects must be at the same temperature. ✓

Exit quiz

Match the following key words or phrases to their definitions.

control experiments

⇔

used to find a baseline results to which others can be compared ✓

independent variable

⇔

its values are selected by the experimenter ✓

dependent variable

⇔

it's values are measured to get a set of results ✓

control variables

⇔

kept constant in an experiment for the test to be fair ✓
A thermometer with a resolution of 0.5°C is used in a cooling experiment. What does this resolution mean?

The highest temperature that can be measured is 0.5°C.

The lowest temperature that can be measured is 0.5°C.

The smallest change in temperature that can be measured is 0.5°C. ✓

The temperature will decrease by 0.5°C each second.

The temperature will increase by 0.5°C each second.
Why is a cardboard lid used to cover a beaker of water during an experiment to compare insulators?

To reduce energy transfer by convection currents. ✓

To keep the test fair.

To stop the thermometer from falling out.

To prevent energy being transferred to water by radiation.

To control the starting temperature of the water.
For a fair test of insulating materials, the ‘amount’ of insulator used should be kept the same for each type. Which of these are ways of controlling the ‘amount’ of insulation used fairly?

keeping the type of the insulation the same

keeping the thickness of the insulation the same ✓

keeping the starting temperature the same

keeping the mass of the insulation the same ✓

keeping the time allowed for cooling the same
A pupil tests different insulating materials by insulating a container of hot water and monitoring its temperature over time. How will they conclude which is the best insulator?

the biggest change in temperature in ten minutes

the smallest change in temperature in ten minutes ✓

the smallest fall in temperature each minute ✓

the greatest fall in temperature each minute
The temperature of hot water fell by 25°C over 6 minutes with 0 layers of insulation, 15°C with 1 layer, 10°C with 2 layers, and 8°C with 3 layers. What conclusions can be made?

Adding more layers reduces cooling. ✓

Adding more layers has no effect on cooling.

The change in temperature is proportional to the number of layers.

The effectiveness of each additional layer increases.

The effectiveness of each additional layer decreases. ✓

Worksheet

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Lesson Details

Key learning points

In a fair test, only the independent variable is changed so that no other changes could affect the results.
The variables that are deliberately kept the same are called control variables.
A lid on a beaker prevents transfer of energy by convection currents.
Gas is a very poor thermal conductor.

Common misconception

Heat is a substance that flows through an insulator.

Always refer to it being particle vibrations that are passed on through a material and do not refer to heat moving.

Keywords

Control experiments - These are done to find a baseline set of results to which others can be compared.
Independent variable - The variable that is changed during an experiment.
Dependent variable - The variable that is measured or observed during an experiment; it changes as a result of varying the independent variable.
Control variables - These are factors that need to be kept constant in an experiment for the test to be fair.