1. Conduction
D. Crowley, 2008

2. Conduction
To know how energy travels by conduction, and to understand the terms conductor and insulator

3. Temperature
It is necessary to know some common temperatures we come across – using the worksheet colour in the thermometer readings for the six temperatures
Temperature: -
In a room: 25ºC
In a fridge: 5ºC
In a freezer: -18ºC
Boiling point of water: 100ºC
Freezing point of water: 0ºC
Freezing point of dilute salt solution: -8ºC

4. Temperature & Heat Remember: - Heat is a form of energy
Temperature is a measurement of that energy

5. Thermal (Heat) Energy
Thermal (heat) energy is one of the forms of energy
The types of energy are: -
Electrical energy - a current in a circuit etc…
Light energy - from the sun; a light bulb etc…
Sound energy - from a loudspeaker; a drum etc…
Kinetic (movement) energy - anything which moves!
Nuclear energy - transferred during a nuclear reaction
Thermal (heat) energy - transferred from hot to colder objects
Radiant heat (infra red) energy - transferred as electromagnetic radiation by hot objects
Gravitational potential energy - possessed by anything with the ability to fall
Elastic potential energy - stretched springs; elastic and rubber bands etc…
Chemical energy - possessed by food; fuels; batteries etc…

6. Heat Transfer
Thermal energy (heat) moves from one place to another because of the difference in temperature between them
The energy transfer is always from hot to cold and it can happen in three ways: -
Conduction
Convection
Radiation

7. Demo The energy is passed quite differently in these 3 processes: -
In conduction, energy is passed from atom to atom – like passing a tennis ball from person to person in a chain to get it from the left to right side of the room…
In convection, energy is carried around by the particles – like carrying the tennis ball individually from the left to right side of the room
In radiation, energy is given off by hot objects, and absorbed by another – like throwing the tennis ball from one side to the other!

8. Conduction In conduction energy is passed from atom to atom
It is the most important type of heat transfer in solids
Vibrating particles pass on their extra vibrational energy to their neighbouring particles

9. Conduction Circus
Your task is to visit each of the stations and answer the question posed there…

10. Station 1 Different spoons How would you describe the 2 materials?
What are the advantages of using a plastic spoon and a metal spoon?

11. Station 2 Different blocks
Describe what you feel when you touch the different blocks
Are all the blocks the same temperature – they have all been kept in the same place during the night!

12. Station 3 Insulators Which is the best insulating material?
How can you tell this?

13. Station 4
Insulators
Feel the three materials – which is the best insulator?
What do they all have trapped inside them?

14. Station 5
Saucepan
Look at the saucepan – what are they made in this way?

15. Conductors & Insulators
Substances that allow thermal energy to move easily through them are called conductors - metals are good conductors of thermal energy
Substances that do not allow thermal energy to move through them easily are called insulators - air and plastics are good insulators
E.g. the space shuttle has very specialised heat shields (10% silica fibre and 90% space) which can withstand the huge temperatures without melting (>1200ºC)