I used to give a lot of these presentations to younger kids,
primarily 5th graders. I always did 3 things, taking about an hour per
1. I used wood furring strips (1x2's), 4 feet long, to
demonstrate beam action. I culled out the good ones and tested those on
edge (strong axis); I used the ones with bad grain and knots for the weak axis
test. (Yes, make sure the demonstration works out the way you want it
to). With 5th graders, we put the furring strips up on little 2x6 stands
and stood the kids on them, then counted how many kids it took to break
them. High school kids, you better pick the thin ones. Then we
compared, and talked about weak axis and strong axis, working around to the fact
that the wood on the outside is more effective than the wood in the
middle. This led naturally to I-beams and then to trusses and joists (keep
reducing less effective material in the mid-depth of the beam).
2. I used drinking straws as columns. I built
little mouse-trap fixtures to hold a full-length straw and a half-length straw,
then piled textbooks on the top of the fixture to see how many each could
hold. The half-length straw, of course, held more. This led to a
discussion of column buckling, then to trussed towers where the diagonals serve
in part to reduce the effective length of the vertical members.
3. I showed them a video of the Tacoma Narrows
bridge. They always asked if anyone was killed. Once, I made the
mistake of telling them that the guy walking drunkenly up the middle of the
bridge forgot his daughter's cocker spaniel in the car (true, as far as I
know). Don't do that.
Even with high school kids, the chance to break stuff is very
compelling. They'll love it. They'll love anything that gets them off
their butts and doing something.
From: Paul Blomberg
Sent: Tuesday=2C January 26=2C 2010 4:55 PM
Subject: Career Day Presentation
I volunteered to give a 20 minute
career day presentation for my wife's school district. The audience
high school age and the career is structural engineering.
Has anyone done this before and
would you be willing to share you presentation outline or slides with