When Liam Pope-Lau was in sixth grade, he fell into the Pacific Ocean during a sailing lesson off Vancouver Island in Canada. Luckily, he was wearing a life jacket! But the water was still extremely cold. Liam and his friend Fraser Tuck wanted to find a way to keep people warm in water emergencies.

The teens, who are now in ninth grade, invented a self-heating life jacket and named it LifeHeat. It contains a pouch filled with calcium chloride (CaCl2). When the chemical meets water, it undergoes an exothermic reaction that releases heat.

The teens experimented with different amounts of the chemical. At one point, they jumped into the ocean wearing a prototype, or testable model, of their jacket—but the vest quickly overheated. “It was a good sign that it worked,” says Fraser. “But it worked too well!” The pair improved their design and were named 2022 Innovators of the Year by the Science Fair Foundation of British Columbia. They hope to start selling LifeHeat soon.