Question

What is capillary method?

Answer 1

Capillary method:

• The capillary method is one of the oldest methods used to determine the surface tension in liquids or gases.
• Capillary rise takes place due to the cohesive and the adhesive forces that force the liquid to rise in the tube through a very small diameter.
• It happens when a capillary tube is placed in a liquid present in the container, the liquid rises in the capillary tube up to a certain distance which helps in the determination of surface tension in liquids.

Level rise or fall in a capillary:

However, the liquid level increases or decreases in the capillary tube depending on

• If adhesive force is more than the cohesive force between the liquid and the capillary wall, an increase in the liquid level takes place. Example: Water
• If the adhesive force is weaker than the cohesive force between the liquid and the capillary wall, an decrease in the liquid level takes place. Example: Mercury