Relevant Resource questions :

Concepts demonstrated :

• Convection.

Click on the picture to see a second picture

• Convection box
• candle
• small rope (smoke source)
• matches
• CCD camera (optional)

• Light rope and allow to burn in right hand tray under column - the smoke will go straight up.
• Now light candle - due to convection, (the hot air rising from the candle), the smoke will now move across the box and rise through the other column.

None.

Physics involved :

This experiment demonstrates convection, which is one of three ways for heat to flow. Hot air rises allowing cold air to enter from a different place.

How to use the Demonstration :

• See "Method for setting up apparatus".
• Use in the course when demonstrating convection.
• This demonstration can be used as POE e.g. "What happens if we light a candle ?"

• convection currents at home
• commercial chimney stacks.
• old fire places in houses.
• Oil heater (compared with bar radiator - radiant heat).

  NB: Reverse cycle air conditioning is more efficient than an element. etc.

• It would be good to add a simple poster for Open Day.

• The demonstration works well but the smoke is not easy to see at the back of the lecture theatre. It might help to blacken the smoke by adding petrol or something of this nature to the rope. It may also be useful to have a larger scale apparatus or "orange smoke" or a CCD camera ? The safety of using petrol may be an issue.
• Convection does not pose much conceptual difficulty.