Making box-on-a-slope problems fun

2015-09-14 17:08

Subject Genius, Stephanie Grant, maths and physics

I had a lot of fun in June for an hour or so when my colleague in the maths department introduced me to a fantastic new resource. We created for ourselves a model of the box-on-a-slope problem. I know - it doesn’t get much more exciting than that. We designed force arrows which changed size depending on the initial conditions we stipulated, we were able to change the angle of the slope gradually, change the coefficient of friction, the list goes on! It was a mixture of mechanics and, I suppose, basic programming. It turned the normal questions students have to answer on their head completely and would require an extremely firm grasp of the theory behind the situation. All in all, a very exciting new discovery! Manipulating given models is an option for weaker students, helping them to ‘experiment’ with the situation to improve their understanding. Creating a model for themselves is a fantastic ‘stretch and challenge’ opportunity. All through the free resource ‘GeoGebra’.

I taught my first Year 13 maths set this last year, mostly doing the Mechanics module, and it was enlightening. My experience of Maths departments in various schools has been mixed – the low point was being told by a student that their Maths teacher told them I was not right to write ‘F=ma’ on the board, that it should always be ‘resultant force’ instead of F. The high point has definitely been teaching some Maths myself and being introduced to some great ideas from fantastic colleagues. And GeoGebra is certainly the best resource I have come across which could really be helpful for Physics teachers too.

If you search for ‘GeoGebra Tube’, there is a bank of ready-made models people have spent ages on and uploaded for people to play around with on all sorts of topics. There are many different ones relating to the linear slope problem. It is hard to use any of them, or to be honest to get very excited about the topic generally, without an understanding of the coefficient of friction. This is not necessarily required by most A-level physics specifications, but if you teach about it anyway then a whole realm of more interesting problems open up for students to solve. It is not really a complex extra thing to teach, and by then using this extra knowledge to manipulate some of the models on GeoGebra Tube your students’ understanding will be very thorough and they will find the more standard questions much easier to answer.

Something which is always tricky about teaching A-level mechanics in physics is that invariably some of your students are studying maths and some are not. For those who are, downloading GeoGebra and challenging them to create their own model is a fantastic ‘stretch and challenge’ activity which should keep students occupied for at least a couple of lessons. And how much more valuably could they be occupied? It is an open-ended, creative, problem-solving task of exactly the sort they should be doing if considering a related subject at university. Creativity is often cited as something lacking from studying maths and physics. We know this is not true, but need to re-think how we teach things for it not to be true at Secondary level. Here is one example of how we can do it.