Question

A bubble of air has a diameter of 1mm when it is 0.5m under the surface of water (coefficient of surface tension 0.073N/m). Find the gauge pressure inside the bubble.

Answer 1

Answer:

In this lecture:

• surface energy is defined,

• the effects of temperature and contaminants on the surface is discussed,

• methods of measuring surface energy in solids and surface tension in liquids are given,

• the angle of contact between liquids and solids is defined,

• capillary action is seen as a surface tension effect,

• the size of bubbles is seen as a balance between excess pressure and surface tension, and

• Laplace's law, for cylinders of fluid.