The force that slows things down in air or water is called drag.

Here's a breakdown:

* Drag is a type of frictional force that opposes the motion of an object through a fluid (like air or water).

* It's caused by the object having to push the fluid out of the way as it moves.

* The amount of drag depends on several factors, including the object's shape, speed, and the density and viscosity of the fluid.

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