ELi5 | SM on Instagram: "An antique gasoline blowtorch worked by using liquid fuel and basic principles of heat, pressure, and combustion to produce a powerful, focused flame. Inside the metal body of the torch was a small fuel tank filled with gasoline. Before lighting, the user first preheated the torch by burning a little fuel in a shallow cup beneath the nozzle. This preheating step was essential because gasoline needs to turn into vapor to burn cleanly and steadily. As the metal around the