1. Fluids

2. What are Fluids? A fluid is any form of matter (substance) that flows.
Both Liquids and Gases can be considered as fluids.

3. Fluids and the Particle Theory
The particle theory of matter provides a model to help understand the differences between fluids and solids.

4. The Particle Theory The Particle Theory of Matter states that:
All matter is composed of particles
Particles are in constant motion
There are forces of attraction among particles.

5. Solids, Liquids and Gases
Particles in solids are close together, move slowly and have strong attractive forces.
In liquids the particles are moving more rapidly and are spaced farther apart. The forces of attraction are weaker so the particles are not locked in a fixed arrangement.
Gas particles are far apart and forces of attraction are so weak that the particles act independently.

6. Demos
Pop Can
Ball ring

7. Viscosity
Viscosity is the physical property of a liquid that limits its ability to flow.
It is the term for the resistance that a fluid has to flowing and movement.

8. Varying Viscosity
The particle theory indicates that small particles can move past each other more easily than large particles. Large particles take up more space.
For example; oil particles are bulkier than water particles, and thus oil is more viscous than water.

9. Thick and Thin
Thick substances like ketchup have a high viscosity (or a lot of resistance to flow...)
Thin fluids, such as apple juice, have a low viscosity and flow easily.

10. Temperature and Viscosity
As particles cool, they lose energy.
A liquid's ability to flow depends on the energy that the particles have to move around.
A fluid's viscosity decreases as temperature increases, and viscosity increases as temperature gets cooler.

11. Motor Oil Why are motor Oils different? What does 10w-30 Mean
What factors about an engine require different motor oils?

12. Questions
Molasses has a high viscosity. Explain what this statement means.
How does the thickness of a fluid compare to its viscosity? Give an example.