[motion picture] Traces the history of jet and rocket engines and diagrams the principles on which they operate. Begins with Hero's model of a steam jet and continues by showing simplified uses of the principle in a rocket toy, a balloon, and a lawn sprinkler. Further diagrams the operation of the reaction engine in a ramjet pulsejet, and turbojet. Shows a cutaway of a turbojet engine and explains its modifications with a ramjet afterburner or a turbo prop. Points out that the difference between jet and rocket engines is that the rocket carries its own oxygen enabling it to fly outside the atmosphere.