Sinan/Compass/The Four Great Inventions

3D Model

Compass, ancient called Sinan, the main component is a magnetic needle mounted on the axis, the magnetic needle under the action of the natural geomagnetic field can freely rotate and maintain in the direction of the tangent of the magnetic meridian, the South Pole of the magnetic needle points to the geographical South Pole (magnetic field North Pole), using this performance can identify the direction.