Question

Why the casing of a magnetic compass is usually made of aluminium?

Answer 1

However, when nickel (Ni) is added to stainless steel the result is usually a non-magnetic form of stainless steel. 13] The casing of a magnetic compass is usually made of aluminium. If a ferromagnetic metal is used, the magnetic  needle will get attracted to it and will not show the correct direction.

Answer 2

Answer:The casing of a magnetic compass is made of aluminium because aluminium is a non-magnetic metal.  Hence, it will not affect the working of compass as any other magnetic material, like iron will attract  the magnetic needle and can cause the compass to show a wrong direction.