Mix And Flow of Matter May. 2014 | Page 6

Flow Rate and Viscosity

A liquid’s thickness or thinness is called viscosity. A thicker fluid would be more viscous

The time it takes a fluid to flow from one point to another is called a fluid’s flow rate.

How does the viscosity of liquids vary

• As temperature of a liquid increases, the viscosity decreases meaning it can move quicker

• As temperature of a liquid decreases (gets colder), the viscosity increases meaning it will move slower

How does the viscosity of gases vary?

• As the temperature of a gas increases, the viscosity increases as there are more collisions between the gas particles. The increased collisions mean it is harder for the gas to move.

• As the temperature of a gas decreases (gets colder), the viscosity decreases meaning it will move quicker

The above relationship is the opposite of liquids.

Importance of Viscosity:

Motor Oil

• Motor oil must be viscous enough to cover engine parts and lubricate them

• However, motor oil must also be thin enough to reach engine parts as soon as vehicle is started

Oil extraction from oil sands

• One method is to use steam and inject it underground

• The steam heats the oil sands and makes the oil thinner or less viscous

• The oil can then be pumped out of the ground

Nail Polish

• Viscosity is important

• If too thin it will flow too fast and dry fast and if too thick it will flow slowly and dry too slow