I'm a high school student and in our course we have elements of earth's magnetic field (dip and other stuff) that lets us know the value and direction of magnetic field at any point on the planet.
I just wondered why is this in high school course so I asked my teacher why we need to know about Earth's magnetic field that much( approx. value and direction at any point on the planet). Like, the only use that comes to my mind is studying how the magnetosphere protects us from radiation, but I don't think it requires us to know that much about it(or does it?). One historical use could be for navigation, but now it's all GPS based.
And my teacher replied sometimes that magnetic field interfere in our experiments or machines and so we need to take into account the disturbance caused by that.
Any examples, on how the magnetic field interfere, or some other reasons we need to know about it?