Magnetic Field Demonstrator

This device is designed to demonstrate the behavior of magnetic fields.  For instance, passing a ferrous object like a Coke bottle cap or a small tool across the surface will cause the little magnets to jiggle, while objects such as guitar picks, keys, and American coins, being non-ferrous, will have no effect.  Placing a magnet next to the device will cause the little magnets to react according to their magnetic properties.  For instance, using a circular magnet will cause the little magnets to arrange themselves in a circular pattern while bar magnets will cause the little magnets to arrange themselves in tightly packed rows.  For the more adventurous, iron filings can be sprinkled on the surface of the device, illustrating even more characteristics of the magnetic field. 

As the magnetic field is a manifestation of the electric field this device also provides an insight into the behavior of charged particles.  While it is not an exact representation, the behavior of the little magnets is a bit like electrons in an electron cloud.  There is a force that keeps them separated even when they are mutually attracted to an oppositely polarized magnet.  Each external magnet will attract only as many little magnets as what balances the strength of the external magnet’s magnetic field.  Thus, a weak magnet will attract only one or two little magnets, while a powerful magnet may attract dozens, while the remaining magnets keep their distance.  This is similar to the differences in atomic nucleuses and their accompanying electron clouds.

In addition to its usefulness as a scientific curiosity, the device can also serve as a fidget device. With an external magnet in hand, one can spend endless minutes chasing the little magnets around the device. 

Printing

Central to the operation of the device is the translucent windows.  The profile that I have provided works well with both PLA and PETG although I think that the SUNLU transparent PLA gives the best results. 

Assembly

The pieces of the device snap together and should not require any glue.

It takes about 60+ 6mm x 2mm disc magnets.  (Bambu Lab item CA004)  The magnets need to all be inserted into the device with the same polarity.  The easiest way to do this is to stack the magnets and then take each magnet in turn off the stack being careful to keep the orientation and then slipping it into the access hole on the device.  If a little magnet is accidentally inserted the wrong side up, a much stronger magnet can be used to pull it out of the device.  The exact number of little magnets is not important, but the more the better.  If enough little magnets are inserted into the device and it becomes saturated, little magnets will begin to jump out of the device’s access hole.  Once a sufficient number of little magnets have been inserted, the clip should then be securely installed.