Book 21, Question 114
Why Does a Magnet Fall Slowly Through a Copper Pipe?
Drop a magnet through a plastic pipe, and it falls fast. Drop it through a copper pipe, and it falls slowly, as if something invisible is catching it!
More fun facts
- Magnets aren't attracted to copper.
- Yet a strong magnet drops slowly through a copper pipe.
- The falling magnet pushes electrons in the copper around in swirls called eddy currents.
- Those currents make their own magnetic field, which pushes against the falling magnet.
- Dropped through a plastic pipe, the same magnet falls straight through almost at once.
Sources: BBC, Exploratorium
Questions kids ask
Will it work with an aluminum tube?
Yes. Aluminum, copper or brass tubes work, but not iron.