A compass,zhǐ nán zhēn,indicates north and south.

指南针可以指示南北。

It was invented by Chinese 2,000 years ago.

2000 多年前，中国人发明了它。

The ancient zhǐ nán zhēn looked like a spoon.

古代的指南针就像一把汤勺。

When the spoon was put on the plate,its handle could point to the south using magnetic fields.

把它放在平滑的盘子上，依靠磁铁的原理，当它静止的时候，勺柄就会指向南方。

Then Chinese used a little steel needle to replace the spoon. This made the zhǐ nán zhēn easier to carry.

后来，中国人用小钢针代替了汤勺，指南针就更轻便了。

Six hundred years ago,Zheng He,a famous eunuch of the Ming Dynasty,traveled to Southeast Asia and the Indian Ocean seven times. Zheng even reached the Red Sea with the help of the zhǐ nán zhēn.

600 多年前，郑和先后七下西洋，最远到达红海沿岸与非洲东海岸，便是依靠指南针的导航。

The invention boosted the development of navigation.

指南针的出现促进了世界航海时代的发展。