Gyroscopic Precession
PRECESSION – Introduction to:
Grade Levels: 6-8
1. Yo-Yos. First, perform the following experiment with a ball-bearing TigerShark yo-yo (by Spintastics).
a. Throw a hard Spinner. Watch it spin.
a. Does it stay in the same plane of spin while it is spinning?
b. Throw it multiple times. Notice that even though a throw may be
somewhat crooked, the spin stays in the plane from which it was throw (at least until the spin dies).
c. Now remove ONE of the “speed rings” from one side of the yo-yo. (To remove it, pop off the holographic side disk on one side of the yo-yo and remove the metal ring you find inside by lifting up from under it with a screwdriver or other such tool.)
d. The yo-yo is now OBVIOUSLY out of balance. If you were to throw a Spinner again, what do you predict will happen? Do you think it will tip over on the heavy side?
Why or why not?
e. TRY IT! Throw a hard Spinner and watch the yo-yo spin. What happens?
What you should see happen is that the yo-yo will begin to turn toward the
weighted side, but will not tip over, as you may expect. This is called precession. It will stay spinning in the plane from which it was thrown, due to gyroscopic stability.
This proves that when a yo-yo is spinning in a crooked manner, it is NOT due to the yo-yo being out of balance. It is because the player is not throwing the yo-yo straight.
(Sorry!)
Gyroscopes.
A simple visual to show precession is a gyroscope. Pull the string in a gyroscope to spin the wheel inside of it. Loop the string around one end of the gyroscope and let go of the other side. Does it fall? No! Would it fall if it were not spinning? Yes!
However, how is it spinning? It isn’t just spinning as it is stationary on the string.
It is actually turning around the string axis. Why? This is precession, as explained below.
Spin Top.
A Spin top is another form of a gyroscope, and therefore will precess in the sameway as a gyroscope when spun and hung on a string.
Gyroscopic Precession says that a spinning object tends to react to a disturbing force by rotating in a direction at right angles to the direction of the force. In this case, the disturbing force is the weight of the heavier side of the yo-yo. Thus, instead of falling the direction of the weight, precession causes the yo-yo to rotate at right angles to that
pull, or toward the side of the yo-yo which is the heaviest.
What demonstrations in the Science of Spin assembly showed precession?
- Gyroscope hanging on the string was turning.
- Spinning top hanging on the string doing Rock the Baby was turning.
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From Dale Oliver of Spintastics
Science of Spin program
Dick Stohr who is a member here
is a part of the Science of Spin program.
Maybe he can help explain more about gyroscopic procession.
And I would like to learn more about the Science of Spin program…
