I am wonder what produce the earth's magnetic field .Can anyone tell me . Besides , I am doing a experiment to measure the horizontal component of earth's magnetic field . I am using a copper (about 16 mm in length) and a power supply of two volt . I use the copper to create the solonoid but suprisingly the ammeter show that there is no current flow in the circuit . That means that the copper cannot conduct electricity . How it can be the copper cannot conduct eletricity since the wire is made of copper .