Objective:
– Shows lowering of the boiling point by reducing the surface pressure on the liquid.
Apparatus:
- 300 ml beaker with coloured water
- glass bell jar
- vacuum pump
- vacuum plate
- “short” thermometer
- electric kettle
Method:
Water will boil quickly at the reduced pressure in the beaker. The thermometer, set in the beaker, shows room temperature during boiling.
Note:
You can accelerate the boiling process by adding hot water to the beaker before vacuuming the system. Apply Dow Corning vacuum grease to seal the base of the bell jar.
Boiling Point at Reduced Pressure
– Video Created at the North Carolina School of Science and Mathematics