Fluids (liquids and gases) flow, some more easily than others. Those with high viscosity (more viscous) flow slowly. Those with low viscosity (less viscous) flow easily. It can be described as the stickiness of a fluid (a liquid or a gas). It is more difficult to move an object through a liquid with high viscosity. Pull and push the plungers on this exhibit.

 

Which plunger was the hardest to move?

Which plunger was the easiest to move?

What do you think that is?

 

 

 

Viscosity is the resistance a fluid has to flow and is caused by internal friction. It makes it resist flowing past a solid mass, or in this case resists against air flowing through the fluid.

If a fluid is highly viscous it means the resistance of flow is high, such as treacle or heavy oils. If a fluid has low viscosity or is non-viscous it has little resistance of flow, such as water.

The liquids in the tube are as follows:

 

Groups and changing materials

Characteristics of materials

Solids, liquids and how they can be separated