Viscosity measurement with the falling ball viscometer

Principle

Due to internal friction among their particles, liquids and gases have different viscosities. The viscosity, a function of the substance’s structure and its temperature, can be experimentally determined, for example, by measuring the rate of fall of a ball in a tube filled with the liquid to be investigated.

Benefits

• Viscosity measurement for two fluids and any mix ratio
• Viscosity measurement for different temperatures possible
• Angle of falling ball viscometer can be changed
• Interdisciplinary use also in applied sciences or physical chemistry

Tasks

Measure the viscosity

1. of methanol-water mixtures of various composition at a constant temperature,
2. of water as a function of temperature and
3. of methanol as a function of temperature.

From the temperature dependence of the viscosity, calculate the energy barriers for the displace ability of water and methanol.

Learning objectives

• Liquid
• Newtonian liquid
• Stokes law
• Fluidity
• Dynamic and kinematic viscosity
• Viscosity measurements