Jumping Ring Induced Current Demonstration

An Electromagnet produces a strong changing magnetic field along its axis (amplified by the iron rod sticking out). This changing magnetic flux induces an emf (potential difference) in the aluminum and copper rings, which means that a current is flowing through the ring. The direction of the current opposes the change in the magnetic flux through the ring. The result is a repulsive force that causes the ring to shoot upward. Dipping the ring in liquid nitrogen lowers its temperature, which lowers its electrical resistance. The potential difference is constant (caused by the changing magnetic flux) so the lower resistance means a greater current in the ring, and a greater repulsive force.

Category:

Science & Technology

Tags:

• physics
• jumping
• ring
• demonstration
• electricity
• magnetism

[Whatevr089]

@gregoriousamadeus The induced current in the ring will appear in order to contradict the field which created it (Lenz's law).

So the ring will always shoot away from the rod as it's field will always be the contrary of the one created in the rod, so they'll always repel each other

[gregoriousamadeus]

@frodomoses nah, it is AC current, the force generated is proportional to the rate of change of current, since the current is constantly changing in a AC circuit, 50/60 Hz, then thats what provides the induced current in the ring, and an opposing magnetic field. im pretty sure with AC you can tell which direction the ring will shoot.

[WontonSandwich]

now to weaponize it

[71296105195]

so if we pumped nitogen into tubes under the roads and placed magnets under our vehicles we could float

[jordanbaker424]

freeze all your warts off yet?

[patrikLJ42]

hey how much force did you send into it and how long are there from one red line to an other ?

[frodomoses]

My dad used to work for the electric company and told me a story about using AC through a coil to throw a rod with a good deal of force. With AC, you can't know which way the rod will shoot, so I guess this demo (always shooting the ring upward) is using DC. I'm just wondering if since the magnetic field from the electromagnet is circular (through the inside, around the outside, and back to the inside) a coil, rod, or ball on the inside of the electromagnet would shoot down, given no barrier.

[BlakeMason2]

I never realized how much rho for a material changes. That is some serious change in force and induced field. Was AC driving a coil under the ring?