Monday, 10 October 2011
1. S=0 A=0
2. S=1/4 A=1/16
3. S=1/2 A=1/4
4. S=1 A=1
5. S=2 A=4
6. S=3 A=9
Mathematics - year 8 level
This sets out to be a good illustration of the function more commonly expressed as y=x2. (Why the teacher has chosen A and S is unclear; these are sometimes used in lower case form as acceleration and distance respectively, but the relationship between them would not then be physically correct.) The important points (S=0, S=1, two points where S<1 and two points where S>1) have been well chosen to illustrate this function, though it would have been useful to have included some more points where S<0 to show what happens when squaring a negative number.
The graph has then been plotted, but sadly this is where the lesson begins to falter. Firstly, axes on the graph should be labelled with 'S' (horizontal) and 'A' (vertical). And the graph that has actually been plotted seems to be more like:
1. S=0 A=4
2. S=4 A=8
3. S=6 A=15
The graph is roughly the correct shape, but is not positioned correctly: it clearly intersects with the vertical axis at A=4. Even allowing for other drawing errors, this is a function more like A=bS2+4. It would also have been useful to extend the graph to S<0.
What is going on on the right-hand blackboard is less clear. There is a drawing of a trapezium, and also the equation 100=S=A, which is hopefully not meant to be related to the function A=S2.
Finally, the teacher should make sure that her students keep their focus on their work. She only has three students, so can't complain too much about the pupil-teacher ratio. The teacher is giving all her attention to the lone male student, allowing the two female students to talk to each other, thus reinforcing gender stereotypes of women in maths, despite being female herself. Sadly, it is this kind of attitude which leads to the 'Math class is tough' talking Barbie and low numbers of women choosing to study maths in further and higher education.
5/10 Shows some promise
(Many thanks to Chris for sending this picture in. Please keep them coming, folks.)