Wednesday, March 21, 2012

Blind Data: Teaching physics to blind students

About 10 years ago RCN admitted two completely blind students, Pawel from Poland and David from Spain. I’d never really met a blind person before so was quite nervous to discover that David had chosen physics HL. David had been blind from birth so all the pictures in his head were formulated from descriptions, touch and sound (not sure about smell and taste). Physics is a very visual subject, small red balls represent atoms wavy lines waves, graphs of motion, potential ‘ills and wells, not to mention the movement. How will I get all this across to a blind person?

A graph is a visual tool that is pretty useless to a blind person. I first tried using special plastic sheets that you write on with a ballpoint pen to make ridges that can be felt. This works OK, but since I don’t write Braille I had to say what the axis represent and the whole process was a bit awkward. Instead of this tactile solution I experimented with whistling the graphs. I could do linear by free whistling, but more complicated graphs were done using a slide whistle. Whatever the x axis was replaced with time then drew out the plunger to match the slope. David got pretty good at matching the graph to the whistle. Sometimes I’d get the rest of the class to close their eyes too, they weren’t bad either. I’d always toyed with the idea of making an application to reproduce graphs as a sound but never got round to it.

Graphs are also used in experiments to see if relationships are linear. David would use the data instead. He could read a column of numbers (in Braille line by line) and be able to determine if it was linear or not. This required an exceptional ability with numbers. I wonder if a sound version could work here too. If the individual points could be played over the rising notes of the best fit line maybe it would be possible to get a feel for the spread of data.

The SMART board has revolutionised physics education. What used to be a set of static images is now animating across the screen, great for sighted students useless for the blind. All the chairs in the physics lab are on wheels so whenever I needed to describe movement David would take flight. He was subjected to constant Forces, Impulse, and torque and at various times possessed momentum, velocity and acceleration. SHM was fun and resonance better, waves were difficult. For gases I could have got the whole class running about but to be honest I never did, there are limits you know.

Taking measurements was rather difficult for David. I thought it would be fine using computer interface so that values could be read from his Braille line but the software wasn’t blind friendly, and could only be navigated with a mouse. I did enquire about the possibility to adapt the software but the company said there simply wasn’t money to be made from the idea. Tut, tut. Wherever possible I tried to adapt the experiments to suit David, I remember we did Ohm’s law on his tongue and for SHM I hung a bucket from the ceiling and he measured the frequency by feeling when it touched his hand.

We experimented with many different techniques, some worked some didn’t. Sometimes he didn’t actually make it to class, on several occasions he overshot Eckbo and had to be picked out of the bushes. When this happened in the dark it was particularly bad since no one could see where he was. I’d like to develop some of these ideas further but maybe HL physics is not the best place to start. There must be something lower down the education chain that is preventing most blind students ever getting that far. Oh, and another thing, he passed!

This article is written by Chris Hamper, physics teacher at UWC Red Cross Nordic.

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