# [amsat-bb] simple ways to demonstrate orbital mechanics. (Earth and Ball)

skristof at etczone.com skristof at etczone.com
Thu Feb 25 16:18:21 UTC 2016

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#5 Sounds fun as well as challenging. Like the old saying goes "Space is
hard!" (Or something like that.)

Steve AI9IN

On 2016-02-25 11:06, Robert Bruninga wrote:

> Our kid demo of orbits uses a large globe. We hang a small golfball
> satellite on a string from the ceiling. There are several demos we like:
>
> 1) Center the globe under the string and the golf ball sticks to the
> globe. (gravity)
>
> 2) Try to push the ball in a circle. If you get a perfect circle or a big
> enough one, you will have an orbit and not hit the earth.
>
> 3) If you have too much vector "up" in any one direction (not circular)
> then on the next pass it crashes into earth.. (all orbits are elipses and
> you don't want part of your ellipse to run into the earth.
>
> 4) Now move the earth about a radius or diameter away from under the
> string. Now try to launch an elliptical orbit where the ball just grazes
> the earth at perigee and goes way out at apogee. You can get a nice
> Molnya orbit.
>
> 5) For GEO transfer, we had a mark on the floor and a mark out 5 earth
> radii where we had a little tiny bowling pin on a pedestal. Here the
> object was to launch the ball from behind the earth so that it would go
> out and intersect the bowling pin and knock it off. Thus demonstrating a
> transfer orbit to GEO.
>
> No, this is not the same physics of a central force (gravity) driving
> Keplers laws, but it is a perfect demo of circular and elliptical paths.
> For example in this case, the orbital speed is the same at perigee and
> apogee (non Keplerian), but still it is an elliptical path with the earth
> at one foci...
>
> Kids love it. Especially #5 is a real challenge. And even #1 is hard if
> you are trying to orbit only 1 inch above a 24" diameter earth globe.
>
> Do not use an expensive valuable globe (from your wife for example)
> because there will be LOTS of crashes from bad "orbits"...
>
> Bob, WB4APR
>
> -----Original Message-----
> From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of
> skristof at etczone.com
> Sent: Thursday, February 25, 2016 9:17 AM
> To: Tom Schuessler
> Cc: amsat-bb at amsat.org
> Subject: Re: [amsat-bb] simple ways to demonstrate orbital mechanics.
>
> Don't forget that you can download data from AO-73 off of the amsat-uk
> website. Their data is great for looking at temperature increase and
> decrease, spin rate, voltage changes in the solar panels as the satellite
> goes between light and dark, and how the battery discharges during the
> dark periods. Easy access and good teaching material.
>
> Steve AI9IN
>
> On 2016-02-24 08:47, Tom Schuessler wrote:
>
>> Hello all, Several of us AMSATers in North Texas will again be representing AMSAT at the annual "Moon Day" at the frontiers of Flight Museum at Dallas Love Field this coming July 16. "Moon Day" is a celebration of spaceflight past/present and future and is also a very large STEM fair with exhibits from many different scientific and Engineering organizations. Many young people including Boy and Girl Scouts are in
>
> attendance.
>
>> Since there is such a large youth component to this event, I have been looking for some fun ways to demonstrate satellites and orbital mechanics to the people who drop by the booth/table. There is a special STEM patch that they can earn by visiting different displays and asking questions/filling out a worksheet. I am looking for simple but creative/fun ways to demonstrate orbital mechanics and also how a satellite like our Fox birds work. I plan to build a big poster with images of different types of orbits, and have already been given an idea on how to demonstrate the different between a geostationary/synchronous orbit and a LEO but would like some more
>
> ideas.
>
>> If any of you have done some similar outreaches and would like to share ideas, please reply on list or off. I would appreciate it much. Tom Schuessler, N5HYP _______________________________________________ Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect
>
> the official views of AMSAT-NA.
>
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> to all interested persons worldwide without requiring membership. Opinions expressed
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> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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