Magnetic induction at your fingertips

The unique behaviour of Spin Flux is based on a special property of magnetic induction described by Lenz's law. The more you know about the mesmerizing phenomenon, the more interesting the product will get. Dive in and see how scientific discoveries from the XIX. century end up providing a satisfying fidget experience.

Direction sensitive eddy-currents

The special behaviour of Spin Flux comes from the magnetic resistance that depends on which way you rotate the ball.

The embedded ball is perfectly symmetrical and its magnetic poles are hidden from the naked eye. But if you start turning the ball, invisible properties come to life.

 

If you rotate the ball in a way that the position of its poles is unaltered, you don't change the magnetic field inside the product and you won't feel any magnetic resistance

 

If you rotate the ball around another axis, you move the poles of the magnet and thus you make a change in the magnetic field that induces electric current inside the conductive metal torus.

 

And since the magnetic resistance is proportional to the speed of the rotation, the quicker you try to spin the ball, the lazier it will feel.

 

 

But why?

Here comes the hard part. 

There is an induced current in a closed conducting loop if and only if the magnetic flux through the loop is changing. The direction of the induced current is such that the induced magnetic field opposes the change in flux.

 

 

When you rotate the ball perpendicular to its magnetic axis, you make a change in its magnetic flux (ΦB), so the right part of the equation becomes non-zero. This induces a voltage (so-called electromotive force, ε) in the body of Spin Flux and since it's made of a conductive metal, electric current starts to flow.

 

Since the inside of the torus is solid, the exact amplitude and direction of the current are difficult to specify, but according to Lenz's law, one property can be said for sure: these currents will flow in a way that the magnetic field they generate will oppose the mechanical rotation of the magnet ball. You feel it as a smooth magnetic braking force that makes Spin Flux an enjoyable item to fidget with.

 

 

 

 

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