The earliest known records of steam technology can be traced back to Alexandria in AD. 75. It was there that the mathematician Hero, also known as "Heros" or "Heron," wrote three books on mechanics and the properties of air and presented plans for a simple steam engine.
Hero's design called for a hollow sphere with bent tubes emerging from either side of it. This mechanism was then filled with water and mounted above a fire. As the heat caused the water inside the sphere to vaporize, steam was forced to vent through the two tubes. This steam-powered propulsion caused the sphere to rotate -- like a wheel turned by bottle rockets.
Hero's method for transforming steam power into motion was the foundation for later steam technology. However, a great number of scientific advancements were necessary before the concepts behind his steam turbine could be put to practical use. Although people like Leonardo da Vinci toyed with the idea of steam power (the inventor suggested in 1495 that steam power could fire a projectile), advancements in engineering and more accurate measurements of temperature and time helped pave the way for the coming age of steam.
In 1606, Giovanni Battista della Porta of Naples recorded his theories about the role
of steam in creating a vacuum. He theorized that if water converted to steam inside a closed container resulted in increased pressure (remember the exploding soup can?), steam condensed to water inside a closed chamber would result in decreased pressure. This new understanding of steam played a vital role in future developments.
In 1679, French scientist and mathematics professor Denis Papin managed to turn della Porta's theory into reality through a surprisingly domestic project: the "Digester or Engine for Softening Bones." The sealed cooking pot was essentially the first pressure cooker. Papin expanded on this device by adding a sliding piston to the top of a closed cylinder full of water. When heated, the expanding steam pushed the piston up. As the steam cooled and became liquid again, the resulting vacuum pulled the piston back down.
In the next section, we'll look at how 17th century inventors began to put emerging steam technology to practical use -- beyond the pressure cooker, that is.