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How do magnetic fields affect the rate of flow of water?Featured science projectScience project video


This science fair project investigates how the magnetic field emanating from a permanent magnet will affect the rate of flow of water through a narrow passage. The experiment will be done using salt solution and tap water, with a magnetic field as well as without a magnetic field.


Under the influence of an adequately strong magnetic field, the salt solution will have a slower rate of flow than the tap water

Scientific Terms

Diamagnetism, diamagnetic materials, relative permeability, magnetic flux



Diamagnetism is the behavior of certain materials that forms an opposing magnetic field when it is exposed to an external magnetic field generated by a permanent magnet. Diamagnetic materials normally have a relative permeability of less than 1, causing them to be repelled by the magnetic field.

The magnetic field from an external permanent magnet will have its flux lines curved away from the diamagnetic materials, resulting in repulsion. The magnetic field will also be slightly weakened by the diamagnetic material.

Water is diamagnetic. It is able to slightly attenuate and repel the magnetic field from an external permanent magnet. This weakening  effect is greater when salt water is used. In theory, if water is able to repel a magnetic field, it should then be possible to slow down the rate of flow of water through a narrow channel, by introducing a sufficient strong magnetic field along the channel.

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Complexity level:
Project cost ($):
Time required:
1 hour for preparation and 1 hour for science fair project
Material availability:
Laboratory access required
Safety concerns:

Basic safety requirements