Try this interesting magnet experiment and watch a neodymium magnet tumble slow motion through a copper tube! Using a simple neodymium magnet and a tube made of copper (or aluminum), you can recreate this fun science experiment for kids.
This experiment takes about 10 minutes.
- short piece of copper (or aluminum) tubing
- neodymium magnet that will easily fit inside the tube
- drop the magnet into the tube
- What did you observe?
- Can you explain what is happening?
This discovery was postulated in 1835 by Heinrich Lenz and today we call this Lenz’s Law. An electric current induced by a changing magnetic field will flow such that it will create its own magnetic field that opposes the magnetic field that created it. What? Can you say that again! The induced current in the copper tube creates its own magnetic field that opposes the magnetic field that created it. This opposing force slows the fall of the magnet. The more conductive the material, the slower the magnet will fall, all things being equal. So, for example, the magnet would fall faster through an aluminum tube than a copper tube. Silver is more conductive than copper. What would happen if you dropped a magnet through a similar sized silver tube (assuming you could get one)? Or if money were no object… what about a gold tube?
- Try different sized magnets
- Try more than one magnet at a time. Does it fall faster or slower?
- Try copper tubes of different thickness and/or different diameter.
- Try copper vs aluminium tube