Question 3
Magnetise a pin or needle by stroking a bar magnet along it in one direction, lifting the magnet before returning; repeat 50 times. Draw and cut out a wax-paper circle smaller than a bowl, mark N, E, S and W, and thread the needle through it in the N–S direction. Float the paper and needle on water. Work under adult supervision because the needle and scissors are sharp. How does this prove that the Earth’s core acts like a giant magnet?
