Question

Why is water not used as a barometric liquid? Give three reasons.

Answer 1

Water is not used as a barometric fluid because of the following main reasons:

1. Water vapourises under vacuum conditions and hence the water barometer cannot depict the true atmospheric pressure.
2. Water barometer will nearly support 10.34 m of water at sea level and logically speaking, it is impractical to have such a long tube, and hence water barometers are not used.
3. Water is not easily visible in a glass tube because water is transparent.
4. At the water-glass interface, the adhesive forces predominate the cohesive force, and hence, the water wets the sides of a glass tube which leads to incorrect readings.