Flotation is the ability of something to float on water or another liquid. A life jacket provides flotation by trapping air inside its foam, which keeps a swimmer's head above water even when they're tired. Ships stay afloat because of their flotation: their hulls are designed to displace enough water to support their enormous weight.

Scientists and engineers use flotation to separate materials. In mining, crushed ore is mixed with water and chemicals that make valuable minerals stick to air bubbles, which then float to the surface where they can be collected. This flotation process helps extract copper, gold, and other metals from rock.

You might talk about testing the flotation of different objects in science class: a cork has excellent flotation, while a marble has none at all. Swimming pools sometimes have flotation devices like foam noodles or inflatable rings to help people who are learning to swim. Understanding flotation helps explain why huge steel ships don't sink (their hulls contain air) and why you bob back up when you jump into a pool (your body is less dense than water).