New
New
Year 7

Thermal insulators

I can use the idea of vibrating particles to explain why wrapping an object in a thermal insulator keeps a hot object warm and a cold object cool.

New
New
Year 7

Thermal insulators

I can use the idea of vibrating particles to explain why wrapping an object in a thermal insulator keeps a hot object warm and a cold object cool.

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Lesson details

Key learning points

  1. Particle vibrations are passed on more quickly between a hot object and conductor than a hot object and an insulator.
  2. Materials that contain trapped air provide good insulation because gases are very poor thermal conductors.
  3. Wrapping an object in an insulator keeps a hot object warm and a cold object cool.

Keywords

  • Thermal conduction - a change in temperature due to particles passing on their motion through the forces between them or by particle collisions

  • Thermal conductor - a substance through which thermal conduction happens quickly

  • Thermal insulator - a substance through which thermal conduction happens slowly

  • Insulation - a layer of thermal insulator around an object to help maintain its temperature

Common misconception

Insulators warm objects up.

Show your class that an insulator keeps an ice cube colder for longer by wrapping one in a conductor (such as aluminium foil) and another in an insulator at the start of the lesson. The ice cube in the conductor will melt first.

For an extended investigation into insulators, provide a range of insulating materials such as cotton, paper, wool, aluminium foil, cardboard and bubble wrap. Pupils can test different materials and pool the results.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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6 Questions

Q1.
What might the temperature be on a hot day?
between 5°C and 10°C
Correct answer: between 25°C and 30°C
between 45°C and 50°C
between 65°C and 70°C
Q2.
What holds the particles in a solid in their fixed positions?
Correct answer: attractive forces between each particle
cell walls
repulsive forces between each particle
the outside layer of the solid
Q3.
Heating a solid causes its particles to more vigorously.
Correct Answer: vibrate, vibration, vibrating
Q4.
Heating a gas causes its particles to more quickly.
Correct Answer: move, whizz, move around, travel
Q5.
How do particles in a solid pass on vibrations to each other?
pulling on each other with strong attractive forces
pushing against each other
Correct answer: pulling and pushing each other
Q6.
How do faster moving particles in a gas make other particles in the gas move more quickly?
pulling on each other with strong attractive forces
Correct answer: pushing against each other
pulling and pushing each other

6 Questions

Q1.
As a hot object cools down, it its surroundings.
Correct Answer: heats up, heats, warms up, warms, raises the temperature of
Q2.
What do you call a material that is an extremely poor thermal conductor?
a conductor
Correct answer: an insulator
a resistor
a semiconductor
Q3.
How many variables do you change during a fair test experiment?
none
Correct answer: one
two
as many as you need to
Q4.
When carrying out a fair test to compare different insulation materials wrapped around a hot drink, which of these are control variables?
Correct answer: the starting temperature of the drink
the final temperature of the drink
Correct answer: the length of time the drink cools for
the insulation material used
Correct answer: the temperature of the room
Q5.
Why is a woolly scarf a good insulator?
wool is a good thermal conductor
Correct answer: wool is a bad thermal conductor
Correct answer: trapped air is a very good thermal insulator
trapped air is a very bad thermal insulator
Q6.
On a hot day, a wrapped ice lolly is covered with a woolly scarf. What will the effect of this be on the ice lolly, compared to one that is not covered?
It will melt more quickly.
Correct answer: It will melt more slowly.
It will melt in the same way.