How far do Magnets Interact?

Most recent answer: 12/31/2016

from how far does a magnet react to another magnet and from which side does it react highest?.pls give exact length in cm.
- faiz (age 10)

The interaction extends to all distances, to the best of our knowledge. It gets weaker with distance, but does not go to zero.  Of course, when it is too weak, unavoidable environmental effects ("noise") will render the interaction unobservable.  The exact distance will depend on how noisy the environment is.

Mike W, Jon T

(published on 12/31/2016)