LOW and behold
Last week was lesson observation week (LOW). This means that teachers visit other classes. I visited a maths class and a chemistry class. The maths class were doing logs which reminded me about one of the questions on the mock exam I gave to my SL students. It was last years time zone 2 paper, the question I'm concerned about is 4d (iv).
If the fractional change in energy when a neutron collides with moderator nucleus is 0.3 estimate how many collisions it takes to change the energy be a factor of 106 ?
So if the number of collisions is n 0.3n = 10-6
nlog0.3 = -6
n = -6/log0.3 = 11.47 approx 12
I think this is a bit tough for standard level.
Back to the chemistry class. The class were doing a practical so Ashok thought it would be more interesting if I took part. The experiment was to find the amount of asprin in a tablet. I had no idea about the chemistry behind the experiment but it was fun to do it anyway. Very reminiscent of the sort of thing I did when I was at school.