The Lee-Tseung Lead Out Theory

[Forever]

http://www.youtube.com/watch?v=EkaIaKzaQ48
This is experiment 4a that demonstrate magnetic repulsion. The magnet is actually repelled by the coil and jump out from the tube.


http://www.youtube.com/watch?v=n_QXr0U_Xgg
This is experiment 4b. It demonstrates magnetic repulsion. The magnet is already inside the tube. The top of the tube is sealed with a Hong Kong one dollar coin. When the magnet jumps up, it will strike the hard surface and bring the whole tube up.


http://www.youtube.com/watchv=bGqx191RjQI&feature=related
This is experiment 4c. It demonstrates magnetic repulsion. The magnet is first placed in the tube. The tube is placed in a horizontal position. When current is passed, the magnet will travel towards the LHS. Due to action and reaction, the tube would move towards the RHS. Since there is a loss of energy of the moving magnet, the net force will be towards the RHS. Thus we see the net movement towards the RHS.

[Forever]

http://www.youtube.com/watch?v=FCz1Byt7fVI
This is experiment 5. It demonstrates magnetic attraction between a coil and a permanent magnet. This is different from magnetic repulsion in 2 important ways. The first is that the force of attraction increases when the distance between the coil and the magnet decreases. The second is that the magnet will not fly out because the coil will attract it back.

There is no need to seal the top. That means there is no physical collision with a hard surface. The magnet will not be damaged because of collision.

[Forever]

http://www.youtube.com/watch?v=Lh0aL69Wu9g
This is experiment 6. It demonstrates both repulsion and attraction. The magnet is placed at the bottom coil which provides repulsion. When current is passed through both coils, the magnet will jump up and carry the whole tube up. The upward force will be greater than either repulsion or attraction alone.

[Forever]

http://www.youtube.com/watch?v=UVghe2gWPfo
This is experiment 7. It wants to show that when one magnet jumps up, it could carry the whole apparatus of two tubes. It hopes to show that while the apparatus is in mid air, the second magnet will help to send it up higher.

However, this particular video cannot demonstrate that effect conclusively. The weigh of the apparatus is too high and the magnetic repulsion force is too low.

[ltseung888]

The choice available:

We can use thick solenoid wires and draw a large current.  We need only a relatively small number of turns to achieve the required result.  For example, the 20 turns of the number 18 wire has resistance of 0.6 ohms.  The current if steady, is 12/0.6 or 20 amps.  This is a pulse current for a short duration.  The 12 V batteries we use can take that.  However, the coils get hot quickly.  If the student keep pressing on the switch without letting go, he would essentially waste the electricity to heat up the wire.

We can use thin solenoid wires, many turns and draw a relatively small amount of current.  For example, 150 turns of the number 28 wire has resistance of 5 ohms.  The current if steady, is 12/5 or 2.4 Amps.  Many adapters on the market can take that.  We do not need to supply battery and the battery charger.  We can additionally protect the adapters with external fuse.  Will a student be willing to wind 150 turns by hand?

In the educational product, we could have some pre-wound coils.  We can also have at least one exercise for the student.  The video that comes with the product will show the use of both thick and thin solenoid coils.

I am inclined towards the thin coil because we can get the student to learn more - with addition of variable resistor and external fuse.  The student will need to be more patient with the 150 turns of wire.  (We do not need him to count but just require him to use up the supplied reel.)

We shall test the two choices with real students in Hong Kong and Shenzhen before releasing the product to the World.