In the confrontation of the globe earth and flat earth models, still believed by many religious oriented people or uneducated conspirationists, the flat earth supposedly doesn’t rotate, because we can’t feel it. It doesn’t occur to flat earthists that the speed of rotation is too small to be felt.
To prove the earth’s rotation, there are several methods; one of them is to use a gyroscope. Commercially available gyroscope available to the great public isn’t suitable for showing the earth’s rotation. They have too much friction and can’t sustain the rotation for very long. Other principles can be used, of course (laser ring, etc.) but are too expensive or inaccessible or hard to understand. There is the geeky Copernitron among other methods.
Ideally a gyroscope should have frictionless bearing and run within a vacuum. Frictionless bearings can be done with permanent magnet arranged in a specific way. There are several demonstrations on You Tube, but nothing was useful for a gyroscope.
I decided to do some experiments with magnets and bismuth. I bough some NdFeB magnets and a chunk of bismuth on ebay. The smaller magnet is supposed to be suspended within the bigger magnet, lined with a bismuth ring (homemade). The picture below shows the bismuth chunk, the two NdFeB magnets in the left, and the bismuth ring on the right.
Here are the dimensions:
big magnet: 3/4″ OD, 1/2″ OD, 1/4″ thickness
small magnet: 3/8″ OD, 9/64″ ID, 1/8″ thickness
bismuth ring: 1/2″ OD, 7/16″ ID, 1/4″ thickness
The bismuth ring was not easy to make; I’m not well equipped for working metal. I made it by melting the bismuth in a 1/2″ diameter mold. I then drilled a hole in the center, working it bigger with a small drill and increasing the drill size. At the end I used a file to get the ring’s final dimensions.
The magnets are magnetized axially. Once the bismuth ring is placed in the bigger magnet, the small magnet can be inserted in the center. When the magnets attract each other, the smaller magnet isn’t suspended in the center; it’s attracted to the side. When the magnets repell each other, the configuration is unstable.
Conclusion: it doesn’t work, yet!