- Atmospheric pressure can be measured by a simple barometer.
- A thick glass tube (at least 1m long) is filled with mercury completely.
- The open end of the tube is covered with a finger and inverted in a trough of mercury.
- The height of the mercury is proportional to the atmospheric pressure.
Using Simple Mercury Barometer
Characteristics of the Mercury Barometer
Q and A
Q: Barometer is usually made up of mercury. Explain why is it not practical to have a water barometer?
- The atmospheric pressure is about 10-meter water, which means it can push the water up to 10-meter height.
- Therefore a water barometer must be at least 10 meters long.
- This is not practical because the glass tube of the barometer may be broken or topple easily. It is also difficult to keep or move such a long tube.