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Gyroscopes Made Simple
Name: Denise
Status: educator
Age: N/A
Location: OH
Country: N/A
Date: N/A
Question:
I have a very curious 5 year old who loves to
figure things out. His favorite toy right now is a
Gyroscope. (This is the 5 year old who asked me today: "Does
energy create electricity or does electricity create
energy?") He wants to know how it works. He is trying to figure
it out and thinks that the air from the spinning rotor is causing
it to turn. The one we have looks somewhat like a top and has an
alloy ball peg on the end which sits on a small pedestal. Is
there an easy, detailed (he loves details!) was to explain to him
how a gyroscope works?
Replies:
Wow!! You have a 5 year old who is asking some very basic questions
that (so far as I can find) do not have 5 year old answers, but
that is the challenge.
I will start, but I do not think that I will have the last
'answer' on my first try.
First, eliminate the air. Yes, that is what you feel, but that
is friction that tends to cause the gyroscope to slow down.
The motion of a gyroscope is far more abstract than that. When
you start an object (the gyroscope) spinning it "wants to keep"
spinning in the same direction and with the same "energy" it has
when you start it spinning. It will slow down due to friction, but
the principle is that in an ideal situation it would keep spinning
at the same "speed" and the same direction that it starts out with.
What determines the speed is the amount of matter (mass) that is
off center from the axis (direction) around which the spinning axis
(direction). Here, an example that is available on TV is an ice
skater at the Olympics in Italy. As the skater brings more of
her/his mass toward the axis of spin the speed of rotation
increases. If the mass (you can call it weight) is not exactly the
same as the axis of spin, the spinning "thing" tries to return to
the beginning direction. But because the direction that it is off
the perfect axis is "left and right" and "backwards and forwards"
the gyroscope will spin in a circle trying to "find" its perfect axis.
If I were trying to explain this to a 5 year old, I would pause
here and see what questions this (incomplete explanation) response brings.
It is questions like this from a 5 year old that brings
scientists to our collective knees. How to "explain" the
conservation of angular momentum in the language of a 5 year old.
Start with this, but it is by no means adequate.
Sorry for a -- not so good -- explanation.
Vince Calder
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Update: June 2012
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