Question

how do we know the north pole and the South Pole on the globe

Answer 1

All magnets have a north-seeking pole (abbreviated to just north pole or N). It is the end that points north. This is often coloured red on a magnet or compass.

The opposite poles of two magnets attract. Therefore, when the red end of a magnet or compass is pointing north, it is because it is being attracted in that direction by the south end of another magnet (often coloured blue) – this is the imaginary magnet inside the Earth.

So, when we think of the Earth as a big magnet, it is the blue south pole of the magnet that is underneath the North Pole of the Earth (note the use of capitals for the place and lowercase letters for the magnetisation).