With huge thanks to the British Geological Survey in Edinburgh, we now have a magnetometer in our school, collecting real data about the Earth’s magnetic field strength and uploading it online. They already have some magnetometers buried underground at different latitudes in the UK but did not have any across different longitudes, and, happily for us, we were keen to place these new ones in schools. There are certainly some drawbacks from a scientific perspective to this plan – small changes in temperature (think of a class of children on a June afternoon with Bunsen burners on in the lab…) and small movements of iron objects in the vicinity (even a car passing outside the building will be registered, such is their sensitivity) can generate fairly significant noise in the data they produce. For us of course, this noise is almost as interesting to talk about with students as the Earth’s magnetic field is.
I personally learnt a huge amount from the scientist who came to install it – both about the structure of the kit and about the magnetic field of the Earth. The magnetometers can detect magnetic storms of the order of 100nT relatively easily once temperature and noise are taken into account as their sensitivity can be around 4 nT, even in a school lab environment. Even their underground magnetometers are not immune from noise though – the other day I got very excited by an ‘Aurora Watch’ red alert which was in fact generated by a lawnmower passing over one of their instruments!
Thankfully, the students will be back soon and I can pretend my excitement is solely for their benefit... which I really do think will be significant. We teach about aurorae to Year 7 and to have a magnetometer in the region, or possibly even in the same classroom, should really help to bring the subject alive. Of course magnetic fields then come up again at all levels and there is a massive opportunity for pupils to actually look at the data it is producing for themselves, most likely using it in conjunction with their computing skills. It is the perfect material for sixth form extended projects, for example.
The live data gets displayed here under ‘BGS Schools’ then ‘Norwich’ (or others of course!) and the three plots relate to the three axes in which the coils are oriented:
I can't wait to see what the students do with this exciting new experiment set up in the department.
Stephanie Grant teaches physics in Norwich