Jun 16 2008
smart scale diagrams
I had a moment last week when I realised that I could model exactly how a problem-solving strategy would look to pupils as they stared down at the jotter in front of them. I was trying to show my new Higher Physics class how to find resultant displacements and forces by adding vectors. This is the first time I have taught the higher course and, while I would probably resort to trigonometry myself, I had to demonstrate the scale drawing method as it can prove useful when several vectors are involved.
I wanted to show pupils, step-by-step, how to measure angles and draw the lines representing the vectors to an appropriate scale. I tried begging an old blackboard protractor from the maths department but there didn’t seem to be any going spare. In desperation, I turned to the SMARTBoard software on my mac, even though the room I was using at the time had no IWB installed†. I found a brilliant protractor and ruler that I could easily move around the screen.
The best thing was that the protractor and ruler are such a good match to the physical equipment the pupils have to use when it is their turn to tackle the problem sheet. Actually that wasn’t the best thing. The total best thing was doing a scale diagram with these tools live in front of the class and coming within 0.4° of the angle they obtained using trigonometry 
†This is probably a gross breach of the EULA. Sorry about that. Yes, really.