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Understanding
Physics : Lives depend on it
Joe
Wolfe, University of New South Wales
A fulfilling day, but tiring. I am a professor in physics
so I do both teaching and research. As it happened, my Day
in Science was nearly all teaching:
I had four lectures today, all to large classes.
Add to this some other work associated with those classes
and there was little time for much else. This is atypical:
for most of the year I'll do rather less teaching than this.
Teaching a
class of 400 students
is a bit like doing a one-man play,
one does have to "perform" on a larger scale and
with enthusiasm and energy. What was the high point of my
day? Well I really like teaching, and today has an interesting
teaching story.
Most of the students in the classes I taught today are studying
engineering. One of the things I like to remind them is that,
when they become professionals, peoples' lives depend on their
quantitative understanding of physics. So, I set up some problems
for them in which a
life really does depend on the correct
answer to a physics problem.Today's
such problem combined collisions, Hooke's
law and energy considerations.
I once saw a clown use a
large hammer to
smash bricks piled on
the chest
of the circus strong man.
It's easy enough to analyse the collision between the hammer
and the brick and to measure the spring constant of someone's
chest, from which one can predict the deformation and force
applied to the chest. This shows that, to minimise the energy
available to deform the chest, it is desirable to have a rather
heavy brick.
So we calculated the minimum required mass for the brick,
included a safety factor, then I lay
on the floor and a student
volunteer used an impressively
large hammer to smash
a large concrete brick.
With several precautions and a careful calculation, this is
not dangerous. However, it looks spectacular and most of the
students take the analysis seriously – after all, a life really
does depend on it -- though of course there were a few calls
for 'let's just do the experiment and find out' or 'try destructive
testing'.
So, this year my 'day in science' was very different. I've
just reread what I wrote for "Day in Science last year
and shall update what was happening then -- partly for the
contrast, but mainly because a few things went very well.
The outreach project I was working on that day was finished
by June 2005, the centenary of Einstein's
theory of relativity. It is called "Einstein
Light", and it has been a success, winning
awards and getting nice reviews.
The study on the effects of age and environment on violins,
subject of an interview that day, was published later that
year. You can read about it on this website: <http://www.phys.unsw.edu.au/~jw/powerhousetwins.html>
.
The materials scientist who visited that day never called
back, but the phone call from the biologist about the cavitation
problem did indeed lead to some interesting collaborative
research in microecology, which is ongoing.
But the best news concerns the short paper I was working on
that day. It was published in Nature, which is a
very selective scientific journal. That story is on my website
at <http://www.phys.unsw.edu.au/~jw/didjeridu.html>.
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