History of the Gyroscope

• The gyroscope dates back to 1743 when the Serson's Speculum sextant was first tested. This sextant used a spinning top with a flat mirrored surface on the top. It allowed sailors find the horizon even when the horizon could not be seen. The word "gyroscope" was first used by French scientist Jean Bernard Leon Foucault in 1852, but it wasn't until the twentieth century that it began being used widely as a stabilizing device on submarines and aircraft, as it often is today.
  
  

Physics of Falling

• Newton's laws tell us that once a force is acted upon an object, that force will continue in the same direction unless an outside force is acted upon it, more famously "an object in motion will stay in motion . . . unless acted upon an unbalanced force." Since the force of gravity is pulling down on a gyroscope, it would seem like it should fall. But it is, in fact, this very same force that allows it to stand through a process known as "procession."
  
  

Procession

• Imagine that there is only one point on which gravity is acting on the gyroscope. If the gyroscope is still, then gravity pulls down on that point, and the gyroscope falls. But if the gyroscope begins to spin, that one point where gravity is pulling moves in a circle. Instead of gravity acting on just one side, gravity acts on all sides as the point moves around, and as long as the gyroscope continues to spin with sufficient velocity, it will balance itself. This is how procession works, although in the real world it isn't a single point being acted on, but all points on the gyroscope simultaneously. What this means is that no matter which direction the axis of a gyroscope is facing, as long as it spins with sufficient velocity, the axis will continue to point in that direction.
  
  

Uses for Gyroscopes

• Because a gyroscope can resist forces perpendicular to its axis, it can be suspended and made to point continuously in a single direction. Doing this with one gyroscope forms the basis of some compasses. Using two together forms the basis for an inertial navigation system. The wheels on a bike or a motorcycle act as gyroscopes and keep the bike balanced. They are also used to help stabilize racing cars, boats and monorails. They create the artificial horizon that pilots use to fly planes. It is even theorized that gyroscopes could be used as part of a propulsion system.