section_path: Types of motor units/Rocket type
section_name: Rocket type
paragraph_text: Rocket type
  
  The aeolipile represents the use of steam by the rocket-reaction principle, although not for direct propulsion.
  
  In more modern times there has been limited use of steam for rocketry – particularly for rocket cars. Steam rocketry works by filling a pressure vessel with hot water at high pressure and opening a valve leading to a suitable nozzle. The drop in pressure immediately boils some of the water and the steam leaves through a nozzle, creating a propulsive force.
  
  Ferdinand Verbiest 's carriage was powered by an aeolipile in 1679.