Why does sea level change? Why is the troposphere thicker at the equator? Why is intrapleural pressure more negative at the apex of the lung? How do gas laws apply to altitude sickness? Why did the terrestrial planets lose their primary atmospheres?
My understanding of viscosity in gases is: 1. The particles immediately touching the surface are considered to have zero velocity relative to the surface 2. particles can (quite understandably) slip from one air stream to another (or, similarly, particles in one air stream influence another), ...