1. Fluids
Viscosity

2. What is Viscosity?
A measure of how easily a fluid’s particles are able to slide past one another.
A fluid’s “thickness” or resistance to flow.
Two major factors that affect
the fluids ability to flow are:
Cohesion
Adhesion.
For the following video, how does
this experiment relate to viscosity?
Viscosity Demo

3. Cohesion
Cohesion is the force of attraction between the particles of a substance. Particles stick together.
Greater cohesion = lesser flow rate = more viscous
Some fluids, such as caramel,
are so viscous that they fold
over on themselves.

4. Adhesion
Adhesion is the force of attraction between particles of a fluid and particles of other substances.
Fluid particles adhere to the sides of containers, pipes, and tubing (e.g., milk in a glass).
Adhesion causes gases and liquids
to travel faster near the centre of
pipes and tubes than at the edges.
But slows down the overall flow
of fluid.

5. Homework Questions
Describe the relationship between flow rate and viscosity.
A: In your own words, define cohesion.
B: Research to find what surface tension is.
A: How does adhesion affect flow rate?
B: Explain why fluids travel faster near the centre of pipes and tubes than at the edges.