Bocce, anyone ?

Bocce is a lawn bowling game from Renaissance Italy.

Modern Bocce sets have eight large balls, in two different colors. The balls of the same color are differentiated by two different patterns of engraved lines, allowing four players with two balls each. A team with red balls, and a team with green balls.

These balls are slightly larger than softballs, but are very hard and quite heavy. Modern balls are made from dense and hard plastic, such as phenolic. In the older days they would have been made from carved and polished stone of differing colors.

As Billiard players bring their own cue-sticks, Bocce players could bring their own Bocce balls.
There is also a small white ball, similar in size to a golf ball. This ball is internally weighted to make it heavy also. Typically it would have an Iron center-weight.
The play of the game is that someone would toss the white ball several yards in a random direction. Then the players would take turns bowling their large balls nearer to the white ball than any of the opponents balls. At the end of a round, the nearest ball would score a point, and all balls of the same color that are nearer to the white ball than the closest ball of the other color, will also score. Then the white ball will be tossed again to start another round.

At the time this game was invented, lodestones (spelled "loadstones" at that time) were laboratory curiosities. The common practice was to have them ground into perfect spheres, and engrave them with latitude and longitude marks aligned to the magnetic poles, to emulate the planet Earth.

Would a Bocce cheater have used his lodestones for Bocce balls, which could attract the white ball, and the player's other lodestone balls, to cheat?

Are there other ways to make a magnet float ?

Yes, there are other methods of making a magnet float.

Floating a magnet is one way to indicate that a substance has become super-conductive. A super-conductive substance provides absolutely no electrical resistance. When a magnet is brought nearby, an electrical current is generated in the superconductor. This electrical current will generate an electromagnetic field of it's own, and always opposing the original magnet. As the magnet comes closer the reverse field becomes stronger, and eventually it will float on the repelling field.
Since this process has no losses, the magnet will float for as long as the super-conductivity remains.

Another way is by utilizing the repulsion between similar poles of two magnets.
The trick is to prevent the floating magnet from flipping over and attracting the base magnet. The Levitron, from Edmund Scientific, spins the floating magnet like a top. The gyroscopic forces keep it from flipping until the rotation becomes too slow, which can take many minutes.

There are also "floating globes".
These devices float a hollow Iron sphere below an electromagnet. There is a sensor, usually optical, that continuously adjusts the power supplied to the electromagnet to maintain a constant float height.
The sphere will float for as long as adequate power is supplied.

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What does "Grade N42" mean ?

The grade number of a Neodymium Supermagnet indicates how
powerfully the individual magnet is magnetized.

The units of measure of a magnet's strength are named after
Carl Friedrich Gauss, and Hans Christian Ørsted. They were
Scientists who studied magnets in the 1700's.

Ørsted's name is re-spelled Oersted because English does not
commonly use the Danish "Ø", so to make the same sound,
English uses "Oe".

The theoretical maximum for Neodymium is Grade N64
meaning 64,000,000 Gauss-Oersteds.
"Mega" is the scientific prefix for million.
So, Grade N42 would be 42 MegaGauss-Oersteds.
This is often abbreviated as "42MGOe" .
Neodymium Supermagnets cannot obtain this full strength
at normal temperatures, but can approach it at near absolute
zero temperature.

As the alloying mixtures and manufacturing processes improve,
Neodymium Supermagnets will become available in higher grades.

I have read that grade N58 has been reached in the laboratory,
and Grade N45 is available at some magnet suppliers.
Some Neodymium magnets may be graded as low as N28.
Grades above N45 are very expensive and are not commonly available.

These higher grades are more sensitive to de-magnetizing
forces and temperatures, and are often kept super-cold from the
moment of magnetizing until the customer receives it.
Some are even shipped non-magnetized, and the customer
magnetizes them in their own facility.

Neodymium magnets are always "charged to the maximum" and
cannot be "pumped up" higher, but if they were subjected to
reverse fields, mechanical shocks, or high temperatures,
they can be recharged if the right equipment is available.

The buyer should pay attention to the Grade Rating of any magnet
they want to buy. Low cost magnets may not have the same "pull"
as more expensive magnets of the same size.

Where is a good place to buy magnets ?

Magnets4less
This site has lots of images and takes a while to load.
They also sell in small quantities, and offer good deals.

Another good place is
K&J Magnetics

This last place sells ... umm ... well ... just about everything the mad scientist could need, including the biggest Neodymium magnets around.
United Nuclear

Where can I see a magnet float ?

There is a video available here.


In this video is a very good float setup because the height of the lifting magnet and the distance between diamagnetic faces are both adjustable. It also looks quite expensive. It uses thick sheets of Pyrolytic Graphite. Less expensive setups are available from K&J Magnetics.
It would be a good challange to build your own frame, a kit containing magnets and Bismuth are available. The frame could be made from wood or plastic, or even non-magnetic metals. Many designs stack things like pennies to make the spacing between the faces, and use long screws to suspend the lifter magnet above the diamagnetic gap containing the floating magnet. The lifting magnet could even be a stack of ceramic magnets,which could be added or removed as needed, but the screw is still necessary for fine adjustment.


Here is a photo of a frame I made from scrap plastic in just a couple of days.

Here it is again with the Ceramic lifting magnets, the Bismuth Diagmagnetic pole pieces, and the floater magnet in place. I am using plastic spacers that are glued to the lower Bismuth Diamagnetic face.

I purchased the Bismuth castings and a number of Neodymiun magnets as a kit from a company called United Nuclear.

A company called K&J Magnetics sells a well made wooden frame with Pyrolytic Graphite faces and several small Neodymium magnets for the lifting and the floating magnets.

The K&J Magnetics frame has an adjusting screw for the lifter magnet, and adjustment for the gap between the diamagnetic Pyrolytic Graphite faces.