Did you know that in 1854, Captain Ward designed one of the first modern life jackets? It was a vest covered with little slabs of cork. Eventually the cork was replaced by watertight pouches filled with kapok, a plant material that was very light and buoyant. Today, the material that makes life jackets float is usually plastic foam.
A life jacket helps you float because it is buoyant. Buoyancy is affected by how much space an object takes up, how much it weighs, and what liquid or gas the object is submerged in. If something is heavy, it needs to also take up a lot of space in order to be buoyant.
We hope that you have a cheerful day at school. Remember to think kind thoughts, use kind words, and do kind things.