Santa finder

Out of the blue one morning, my son asked me if there was a way to work out which direction Santa lived in.  He seemed to have a hazy memory of working out which way the North Pole was earlier in the year and said it would need to spin in a bowl of water.  He was describing a compass that we've made before using a bar magnet, but I rather liked the idea it was a Santa finder, so the next morning he found a bar magnet with an arrow stuck on with a Santa sticker located at the North pole of the magnet!

The Santa finder (which strongly resembles a bar magnet)

I asked him to trace the letters spelling 'North Pole' on a piece of paper and draw an arrow so we could align it with the direction the Santa finder pointed.  We then half-filled a mixing bowl with water and floated the magnet in a smaller plastic bowl inside.  You need the smaller bowl to be able to spin freely, and not sink.

The bowl with the magnet in it spun, then wobbled backwards and forwards before settling on a direction, and we aligned the arrow he had drawn to the arrow on the magnet.  He was very pleased to have worked out which way the North pole was, but he wanted to check it was right, so he set the bowl spinning again and after a minute or so it settled on the same direction.  We talked about how it was actually a magnet, and when the little one peeled the Santa sticker off the magnet he noticed that it had N written on underneath to indicate that it points to North.

Direction of the North Pole from our house

He asked me whether it really points to the North Pole, to which I answered yes.  The answer is a little more complicated, as there's a difference between true North (the North Pole is at true North, and the Earth rotates about the axis between this and the South Pole) and magnetic North.  Magnetic North is a point which is about 500km away in the Canadian arctic, which can move as the Earth's magnetic field shifts (due to changes in the molten iron core of the Earth).  So if you actually stood at the North Pole, your compass would point towards Canada, but as we're not intending to venture to actually see if Santa is there, I didn't attempt to explain this!