Made a water based compass- early navigational tools

I was deciding what crafts to do for early explorers. Megan wanted to make a telescope.  We looked this up and realized this came later than our current explorers, de vaca, Coronado, and even La Salle.   We then looked up a compass and read it was first created by the Chinese, probably during the Qin dynasty (221-206 B.C.).We then read about lodestones, which were invented around 850-1050 A.D.A loadstone was a mineral containing iron oxide which aligned itself in a north -south direction.