Hacked Gadgets Forum

June 28, 2010

Lenz’s Law – Magnet falling slowly in Copper Pipe Demonstration

at 5:07 am. Filed under Complex Hacks, Educational


If I learnt about Lenz’s Law in high school I must have forgot about it. Watch the cool demonstration above where a stack of neodymium ring magnets are dropped into a copper pipe. Of course copper is a non magnetic metal so the magnets will not stick to it. You would probably guess that the magnets would simply fall at the same rate as if they were just dropped. Well if that is what you thought you would be mistaken. Due to Lenz’s Law the magnet falls very slowly through the pipe. Watch the video below for a good explanation of what is going on here.

“Lenz’s Law applies the principles of energy conservation to situations that involve forces in electromagnetism. To see an example, move a magnet towards the face of a closed loop of wire (e.g. a coil or solenoid). An electric current is induced in the wire, because the electrons within it are subjected to an increasing magnetic field as the magnet approaches. This produces an EMF (electro-motive force) that acts upon them.”