Boiling water in a paper cup
Other Relevant Demos :
Simple conduction apparatus.
Thermal conductivity of wood and metal.
Relevant Resource questions :
Diagram of apparatus
- Heat transfer by conduction
Equipment needed :
Method for setting up apparatus :
- paper cup (or paper folded into a box)
- bunsen burner
- wire gauze
- CCD camera (optional)
Accessories (ie posters etc) :
- Place a cup (or paper folded into a box) half filled with water on top of the wire gauze as
shown with the bunsen burner underneath.
- Light the bunsen and heat the water in
Physics involved :
The heat produced by the bunsen burner is absorbed by the
material on the wire gauze and is slowly transferred to the paper cup, hence
heating the water. Because no flame strikes the cup and since the heating is
slow the cup does not ignite.
It is the rate of transfer of the heat through the paper, rather than the boiling point fo the liquid, which causes the water to boil but does not cause the paper to burn.
How to use the Demonstration :
Everyday examples :
- Set up the apparatus and ask students what they think will
- Perform the experiment demonstrating that the cup does not burn and that the water boils.
- Ask students to explain what they observe.
Things to do or add :
- Divers welding underwater
Other Comments :
- Compare a wooden cup to a paper cup. Why do they differ?
- Use and oxy-torch instead of a bunsen burner. Again compare the results and explain any differences.
for any comments.
This page last updated 13th June 1998 by Pal Fekete.
Copyright © 1996 School of Physics
The University of Sydney