3B SCIENTIFIC® PHYSICS |
® |
|
U45051 Diamagnetic Levitation Apparatus
Instruction Sheet
1/04 ALF
|
|
|
7 |
1 |
Base plate |
|||
|
|
|
|
|
|
|
||
|
|
|
|
8 |
2 |
Plastic bell housing |
||
|
|
|
|
|||||
|
|
|
|
|
7 |
3 |
Plastic plate |
|
|
|
|
|
|
4 |
Graphite plate |
||
|
|
|
|
|
|
6 |
||
|
|
|
|
|
|
5 NdFeB-magnet |
||
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
6 Retaining ring |
|
|
|
|
|
|
|
|
|
7 Hex nut |
|
|
|
|
|
5 |
8 Ring magnets |
|||
|
|
|
|
|
|
||||
|
|
|
|
|
|
4 |
|
||
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
3 |
|
||
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
2 |
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
1 |
|
|
|
|
|
|
|
|
|
|
|
The Diamagnetic Levitation Apparatus allows the demonstration of the mode of action of diamagnetic materials.
1.Safety instructions
•Keep all the magnets away from electronic equipment, magnetic media and delicate instruments.
•The ring magnets are brittle and may break if dropped.
•The graphite plate are easily broken or scratched. Handle with care.
•The cube shaped magnet is very brittle and may break merely by flying to the ring magnets.
•Use only finger pressure to tighten the hex nuts.
•If needed clean only with mild dish soap. Do not use abrasive cleaners or solvents.
2.Description, technical data
Within a plastic bell housing there are two graphite plates. Between these plates a cubic shaped NdFeBmagnet, plated with 24K gold, levitates freely. The gravitational force acting on the magnet is almost entirely counteracted by the force of attraction from a ring magnet located above the plastic covering. The two diamagnetic graphite plates, one above and one below the NdFeB magnet, compel it into a stable equilibrium since both poles of the magnet are repelled by the graphite plates (diamagnetism).
Dimensions: |
|
Base plate: |
95 mm x 95 mm |
Height: |
135 mm |
2.1 Scope of delivery
1 Levitation apparatus
2 Transparent plastic plates
1 Socket wrench
3. Theory
The physicist S. Earnshaw proposed the following theorem in 1848: it is not possible for charges or magnets to be placed in a stable levitated state in a static field obeying an inverse square law. He further stated, however, that it would be possible to achieve this with the help of diamagnetic materials.
The availability of very powerful rare-earth metal magnets has made it possible to design a levitation apparatus such as this using graphite as the diamagnets.
Diamagnetic materials are repelled from both magnetic poles.
The action of this levitation apparatus may be understood in terms of either forces, or potential energy. The force of earth's gravity pulls downward on the cube magnet, while the ring magnets exert an upward force. The position of the ring magnets is chosen in such a way, that the two forces equal each other. If the gravity is stronger than the force of attraction, the cubic magnet will fall down. In the opposite case it will move upwards.
The diamagnetic property of graphite effects the cubic magnet in such a way that it is repelled from the respective plate. This force is tiny but it is enough to stabilize the NdFeB-magnet in a state of stable equilibrium.
To get a deeper understanding of the state of equilibrium we look at the potential energy of the cubic mag-
4
Loading...