The Mutual Induction apparatus is a strong and high quality pair of coils such that the small coil of about 420 turns of heavy wire fits inside the larger coil of about 1200 turns of finer wire. An iron core fits inside the smaller coil to make a complete set. The sizes are arranged such that the set of 3 items hold together when lifted as a set. Experiments include a magnetic field of one coil inducing a voltage in the other coil, the effect of iron in a magnetic circuit, the basic transformer theory, making electromagnets and more.