# How to Build a Magnetic Levitating Top

## Step 9: Adjust the Orientation and Height of the Base

Now is the time for a few steps with a lot of text and no pictures. It's just really difficult to explain dynamic problems with static text, so check the video in step #1 to see how this works.

Put a flat sheet made of non-magnetic material on top of the plastic container and try spinning the top. Good chance it won’t not only levitate but spin as well. Several things could be wrong with it:

* The big magnet is placed upside down. Remove the cover and slowly lower the top on it. If, while lowering the top, you won’t feel anything then it you feel like the top is sitting on a magnetic pillow then it’s the wrong side. Flip the large magnet over. Now the top feels some resistance while you’re lowering it, than the big magnet starts pulling it inside the hole. That’s the right orientation. Put the cover back.
* The top is too high above the big magnet, so big magnet repels it and once you spin it it will fly away instantly. Reduce the distance from the top to the large magnet by lifting the large magnet. Washers and bottle cups will help you to lift the large magnet.
* The top is too low above the big magnet, so big magnet attracts the top too much and gyroscopic force is not enough to keep it straight. In this case it falls and tumbles immediately after you release it. You need to increase the distance between the top and the magnet. You can do it by lifting the plastic container on washers of bottle cups, for instance.

The perfect position for the top is slightly below that point when big magnet stops repelling the top and starts attracting. Adjust the height of the magnet under the plastic container so the top is located exactly at this position when you try to spin it. You can also move the small magnet alone the top stem to fine-tune the setup.
Please note that in this position you might need to push the top down slightly while spinning it. If you find this inconvenient feel free to reduce the distance between the magnets a bit more.

In fact one more thing can go wrong with spinning: the speed.

* If you spin the top too slow it will start precessing too much and fall too quickly
* If you spin the top too fast it will start precessing even faster and fall too.
* Spin the top not too fast and not too slow. In fact start from the slow side and keep increasing the speed until you reach the maximum speed after which the top goes crazy.

Besides just the initial spinning the spin-stabilized magnetic levitation only works at speeds between 1000 and 3000 RPM (revolutions per minute). So spinning the top faster than 3000RPM won’t help to keep it flying longer.

Once you positioned the top properly it should be able to spin stably on sheet. In fact if you are lucky and patient you can position it in a point at which it will self-stabilize itself. Even if you spin it not too well it will will eventually straighten up.

Oh, and one more important thing is where you start spinning - it should happen exactly above the center of the large magnet, otherwise the small magnet will tumble and not spin at all.
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