NECESSARY TO MAKE THIS EXPERIMENT:
2 circles of plexiglass diameter 100 mm. x 4 mm. with a central hole of 10 mm.
16 small nails of 15 mm. x 1.5 mm. to be included within the circle of plexiglass with holes of 1.5 mm.
1 wooden bar 200 mm. x 10 mm.
The maximum distance between the two circles of plexiglass in the wooden bar must be 120 mm.
8 plates of copper or brass 15-20 mm. x 0.4 mm. bent in a semicircle with the same diameter of the wooden bar. The plates of copper are to be glued over the wooden bar with the hot glue. See the minute 0:58.
4 coils of copper wire of 0.18- 0.20 mm. wrapped with 160 turns each coil.
The coils are shaped as rectangle, see the minute 1:08.
The four coils must be matched between the two circles of plexiglass at the distance of 120 mm. See the minute 1:34.
The ends of the wires of the coils must be soldered with tin on the sides of the plates of copper. See the minute 1:18.
Important: The ends of the wires of the 4 coils must be placed on the plates and out of phase by a quarter between the plate of the right and the plate of the left. See the minute 1:15 and minute 1:23.
2 ball bearings of 26 x 8 x 10 mm. ( the hole is 10 mm.)
The ball bearings have to be housed on two pieces of wood and shaped as form of half of the bearings, they are glued with hot glue. See the minute 1:50.
2 magnets of speakers of medium size "do not use neodymium magnets."
2 drawing pencils of great thickness.
2 alkaline batteries of 9 -volt.
The batteries must be placed in series to provide 18 volts.
2 cables of copper wire with terminals, black and red or other color.
The wires should be one to the negative and one to the positive.
The other ends of the wires are attached to the rear of the pencils with the bare copper wire. The wood that covers the graphite of the rear part of the pencils must be removed.