Here's a breakdown:

* Viscosity is a measure of a fluid's resistance to flow. It's essentially the internal friction within the fluid.

* Fluids include liquids and gases.

* Moving particles within a fluid interact with each other. These interactions create resistance to the flow. The stronger the interaction between particles, the higher the viscosity.

Think of honey and water. Honey is much more viscous than water because the particles within honey interact more strongly. This means honey flows more slowly than water.

Let me know if you'd like to learn more about viscosity!