hi there , When a North Pole of a magnet is made to oscillate in the direction of earths North Pole magnetic field. Also When a south pole of a magnet is made to oscillate in the direction of earths north pole magnetic field . I then measure both of there period of oscillation When doing this practically. The period of oscillations that I get ,I don’t fell it’s very reliable or accurate. So I’m thinking there may be physical factors that are effecting the periodic oscillation. This may be due to the place I’m doing the experiment in i.e. on top of a table might effect, because the table has some metal parts (i.e iron ,not aluminium…) also the building structure I’m inside .(most building are made from metal(steel) and concrete ) And finally the electrical appliances and electric wires, which are carrying current and ones that have magnets in them such as loudspeakers, motores … may have an effect. I can only think of these, is there any more physical factors? Also how could I improve this experiment? Thank you for reading this, I would very much appreciate if one could help me, asap.