In the PADI Open Water Diver course, students are taught to drop their weights in order to gain sufficient positive buoyancy.
This skill is used in case of a surface emergency where the diver can't float.
It is important that students kick constantly to keep their head out of the water while performing this exercise. They must also drop their weight system (belt or weight pockets) and not hand it to anyone or put it on the pool side.
If they are still not positively buoyant, they can inflate their BCD orally, as if they were out of air.
This exercise can be performed in confined or open water where it can also be combined with the Controlled Emergency Swimming Ascent.
Click here to watch the demonstration presented by Platinum PADI Course Director Guillaume Fargues