Ten people drown every day in the United States. 88% of these were not wearing life jackets. Life jackets are now much different than the orange vests commonly envisioned and they are collectively known as Personal Flotation Devices or PFD’s. Life jackets save lives because they are more buoyant in water than people are – they float, you don’t. Buoyancy is the force that counteracts the force of gravity that wants to make you sink. The buoyant force is due to the difference in density between the water and the life jacket.