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Sunday, April 22, 2012

Gyroscopic Effect

Our neighbor’s child who must be just 4 or 5 years old, has a small two-wheeled bike and I was watching today as his father was helping him learn to ride it.  His dad must be aware of the gyroscopic effect  because if you click on the video it shows how he got his boy moving fast enough so the bike wheels were like gyroscopes and had a strong tendency not to tip over.  The gyroscopic effect is somehow peculiarly non intuitive, perhaps because we don’t play with spinning wheels ordinarily and so we’re not used to the fact that any spinning disk tends to continues to spin in the plane in which it is spun and it takes considerable energy to move it out of that plane.

A really neat way gyroscopes are used nowadays is in Segways. They have gyroscopes spinning in their wheels that keep them vertical when you ride one and also the gyroscopes are involved in steering.  Riding a Segway feels like nothing you've ever experienced.  As the video shows,    to increase your speed, you just push the handles forward and then pull back to stop or go backwards.  To turn left or right you use the handlebars like a bike.

It was in the late 1920s that gyroscopes were used to control a ship's roll, first for warships and then in passenger liners. As you’d expect, the heavier the disc is and the faster it is moving, the harder it is to tip it over so gyroscopes on ships weigh tons and they are kept spinning with motors.

In airplanes and helicopters, besides the fact that gyroscopes give them stability, they are essential because, if there is poor or no good view of the ground, the pilot depends on the horizontal position that the gyroscope maintains to tell whether the plane is climbing, diving, or banked left or right. 

Gyroscopes are also tremendously important now for world communication systems because they can keep stationary satellites oriented precisely in a specific direction so they can receive signals from a transmitting station on Earth and then redirect it to a receiving station in another part of the globe. Some of the more than 3,000 satellites now in orbit handle all long distance calls on cell phones as well the important Global Positioning System [GPS] so much counted on now to direct travelers to their destinations.  
The famous Hubble telescope that orbits the Earth, often must use very long exposure times to capture the spectacular pictures of galaxies in deep space. That means it has to be extremely stable to keep the telescope precisely pointed for extended periods of time and, for that reason, there are 6 of the best kind of gyroscopes in the world on board to do the job.  As you can see from the picture of the telescope, it has solar panels that supply the electricity that is needed to keep the heavy gyroscopes spinning very fast.

I find it fascinating that simple spinning discs are used to make so many useful and important systems possible and I hope you do too!   Rie