Te Reo Physics Resources

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Eddy Current - Tubes | Ngā Ngongo Aurere


A non-magnetic pellet falls quickly through a conducting aluminium tube but a magnetic pellet falls slowly.

Principles Illustrated



English version

Te Reo Māori Version


These devices can be purchased at fairly reasonable cost but we can bring ours to your school if you are in the Wellington area. Drop first the non-magnetic pellet and then the magnetic pellet through the aluminium tube. The demonstration can be extended by dropping the pellets though a plastic tube and an aluminium tube with a slot cut along its length. If students are uncertain where the energy in the currents goes, give them a hint by showing Boil Up.

Conservation of Energy
Conservation of energy is a major emphasis
Conservation of Energy
Conservation of energy is a major emphasis

Other Information


This demonstration uses rare earth magnets. You really can get a serious injury from large rare earth magnets. Care must be taken even with relatively small rare earth magnets such as the ones used here. Swallowing a rare earth magnet is particularly dangerous.
See the Eddy Current Drag resource for additional information.
Individual teachers are responsible for safety in their own classes. Even familiar demonstrations should be practised and safety-checked by individual teachers before they are used in a classroom.

Magnet Warning
Magnet Warning
Magnet Warning 2
Magnet Warning 2

We have lots of eddy current resources. See for example Eddy Current Vanes, Eddy Current Drag, Jumping Ring, Boil-up

Notes, Applications, and Further Reading

Eddy current drag is used to make brakes in certain applications. See for example the following exchange on physlink: eddy currents brakes. Also see a discussion of eddy currents in Wikipedia. See also a discussion of Induction Stoves.


This teaching resource was developed by the Te Reo Māori Physics Project with support from