Question

say you were to make a compass using water, needle, a cork, and a magnet at home. will the size of the magnet make it move quicker?

Answer 1

A compass needle moves due to the magnitude of magnetic field created by a magnet.

Now this magnitude of magnetic field depends on

1. Magnetic moment of magnet

2. Distance of needle from magnet's centre point

Now in the above situation factor 2 doesn't change but factor 1 (i.e magnetic moment ) does change

Magnetic moment of a magnet is product of pole strength and the distance between the two poles( i.e. size of magnet).

So increasing size of magnet will increase the magnetic moment and hence alternatively magnetic field .

So it will make the compass needle move faster