What is a compass? Why was it important to ancient Chinese sea travel?

         A compass is a navigational device known to tell the directions of N (north), E (east) , S (south), and  W (west).  Magnetized power is used to control the compass.  The magnetized power comes from earths magnetic field.  The compass was invented in ancient China in 247 B.C.  Its important  for Chinese sea travel because it gave them direction so they knew what way they needed to travel.