Magnetic pendulum

What you can do here
Tilt all the pendulums from the balance position at the same time and watch how they move.


How it works
The pendulum hearts are strong magnets. A magnetic field forms around them. Under the pendulums there are plates made of various materials: copper, aluminium, brass and stainless steel. When the magnet moves over the metal plate, its magnetic field induces eddy currents in it. These currents are the source of a magnetic field with such a direction and sense of a vector that the interaction of magnetic fields results in slowing the movement of the pendulums. The described effect is the most powerful in case of plates that are good conductors of electric current.


Interesting facts
To create a very strong magnetic field, the so-called superconductors are used. These are materials in which the electrical resistance disappears completely. This phenomenon usually occurs at very low temperatures, therefore liquid nitrogen with a temperature of minus 200 degrees Celsius is used for cooling. Cheap high-temperature superconductors are also intensively investigated. Potential success will probably change our lives significantly.
In 2015, one of the car producing companies made a levitating skateboard in which the described effects were used. It was a reference to Robert Zemeckis’ film Back to the Future.