In a previous demonstration, we put a boiled egg into a flask with a mouth narrower than the egg. The challenge is now to remove the egg from the flask without breaking it.
- Bunsen burner or candle
- Pour some water into the conical flask.
- Invert the flask quickly over a tray such that the egg seals the mouth of the flask, preventing the water from coming out.
- Light a flame and place the part of the flask with water over the flame. This will help prevent the heat from cracking the flask.
- Place a tray under the mouth of the flask as the egg slides out to prevent a mess.
The flame heats up the air and the water in the flask. The heated air expands while some of the water vapourizes. With the increase in amount of gas and temperature, the pressure within the flask increases.