How do you prevent undue magnetic influences on a compass?
Preventing other magnetic fields from affecting a compass is difficult, because the earth’s magnetic field is relatively weak. Just in the home there are many things that can influence a compass, from the electrical wiring to the loudspeakers of a hi-fi. The best way to avoid these influences is simply to keep the compass far enough away from them. However, a magnetic shield can be built by simply housing the compass in a hollow iron container, but this will obviously also shield the compass from the earth’s magnetic field.
