A: Qingmuyuan is rich in iron, the compass could not point to the correct direction.
青木源含丰富铁矿，指南针无法指向正确的方向。
2
In the experiment, the compass detected magnetic fields with a strength between 0.1 gauss, which is less than the Earth's magnetic field, and 200 gauss, which is stronger than a small iron magnet.
在试验中，罗盘探测到的磁场强度范围从低于地球磁场的0.1高斯到高于一小块磁铁的200高斯。
3
The iron in the ship caused a deviation of the magnetic needle of the compass .