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.

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.

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.

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

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).

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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.