Question

When a glass capillary tube is dipped at one end in water, water rises in the tube. The gravitational potential energy is thus increased. Is it a violation of conservation of energy?

Answer 1

No, this is not a violation of energy conservation.

Explanation:

This can be explained for two reasons :

1. The potential gravitational energy of a part of the water which rises in the pipe increases, but at the same time the residual water level decreases according to the surface of the water. Part of the high P.E. is compensated by a drop in this water level.

2. The work of the vertical component of the net force resulting from the surface tension around the meniscus is stored as a net increase in the potential gravitational energy of the water in the pipe.

Answer 2

Conservation of energy

Explanation:

No, it not a violation of the conservation of energy because of the following reasons:

1. When one end of a glass capillary tube is dipped in water, water rises in the tube. The gravitational potential energy of this water in the tube is compensated by the gravitational potential energy of the water that lowers outside the tube, which will be proportional to the level of water risen inside the tube.
2. The work done by the vertical component of the net force due to surface tension around the meniscus is stored as the net increase in the gravitational potential energy of the water in the tube.