As early as the 13th century, the Italian Marco Polo sent the compass needle made by the east to Europe. Bele Zininus, a professor at the University of Paris in France, made a serious study of the incredible magnets from the East.
He put the magnet on the board, floating the board on the water, then found the board carrying the magnet is always pointing north and south direction. He put the iron plate rubbed by the magnet on the above-mentioned plank, and when he placed the plank on the water, he found that the plank also pointed north and south. Why does the iron plate that has been rubbed by the magnet have magnet properties?
Gilbert, a British doctor, also did experiments with Beile Zininus, cutting the magnets in half and placing them on a wooden board, floating them on the surface of the water and observing that the cut magnets still point to North-South direction. It has also been found that the mutual exclusion occurs when the south pole of one magnet is brought close to the south pole of another magnet (or when the north pole and the north pole are close to each other), and the south pole of one magnet approaches the north pole of another magnet Close to the Antarctic), mutual attraction occurs and he calls this interaction force magnetic.
Gilbert studied why the magnet could point north and south. By experiment, it is known that the south pole of one magnet attracts each other and the north pole of another magnet, so he thinks whether the earth itself is a big magnet? The poles of the earth are poles, which attract the small magnets on the ground to point north and south.
To this end, Gilbert milled out a model of "Little Earth" with large pieces of magnetite ore, then found the "Little Earth" in the Antarctic and the North Pole and observed the "Little Earth" with a compass needle used by seafarers. The compass The needle points to the north and south poles of "Little Earth," a situation that is exactly the same as when a compass needle points north and south on the ground. Gilbert proved in this experiment that the Earth itself is a big magnet of the conjecture.