Terminal Velocity on Castle Crag

We went up Castle Crag and had a lovely time in the snow. The flakes are falling but not accelerating. They are clearly going at a steady speed. What happens is that when they leave the cloud, only the force of gravity acts on them. So there is a resultant force, because at that point in time there is no counter force, only the driving force of gravity. So the flake speeds up. As it speeds up, the air resistance counter force increases. So the difference between driving force and counter force is less. It still accelerates but not by as much. But it did speed up a bit, so air resistance goes up again by a bit. Eventually, air resistance counter force is as big as the gravity driving force but they act in opposite directions so the resultant force is zero. Now there is no acceleration so the flakes carry on at a steady speed. This is called the TERMINAL VELOCITY. Later the flakes were much smaller, more like pellets. With a smaller surface area they experience less air resistance so they have to accelerate more to before the air resistance is as big as gravity. They have a higher terminal velocity and were visibly falling faster, And if you were wondering what the view was like before the snow started falling...