Fluid Friction

Have you seen a feather drift slowly through the air? That’s because air pushes against it — that push is called fluid friction.

Fluid friction, or drag, is a type of resistive force that occurs when something moves through a fluid like air or water.

Think about swimming. When you move your arms and legs, the water resists your motion — that’s fluid friction too.

Now try this: Wave your hand through water. You’ll feel drag from the fluid. Try the same with cooking oil — you’ll feel more drag because oil is thicker than water. That thickness is called viscosity.

Next, picture riding a bike. The faster you go, the more air pushes against your body, because higher speed means more air resistance.

Imagine a skydiver. When he opens his parachute, air resistance slows both the parachute and the skydiver.

The parachute experiences greater air resistance than the skydiver’s body because the larger an object is, the more fluid friction it faces. So, a larger surface area results in more drag.

Fluid friction depends on several factors, including speed, size, shape, and the type of fluid the object moves through.