intro to engineering ideas

huangyhg

intro to engineering ideas
our firm goes to local middle and high schools to talk to the students about a career in engineering. all of the material that we have is from the 1980's and is kind of lame. my boss just wants us to go there, show an old video and tell the students what classes they need to take in highschool to prepare them for an engineering college. boring!! i would like to maybe incorporate an activity or show some more up to date material. does anyone have any ideas or suggestions? keep in mind, this presentation is only 1 class period long.
thanks
try and find some footage from one of the many history channel shows featuring engineering: "modern marvels", "build it bigger", "extreme engineering", etc.  i'm not sure of the legality of recording the program and showing it though.
a practical demonstration would be pretty interesting.
a few basic ideas:
2 empty coke cans one empty, one filled with sand, ask them to guess which one will take the most load.
a demo involving water.
a buckling demo using a plastic ruler (bending/compression around strong and weak axes) then put a restraint in the middle and demonstrate how much stronger it is.
this is a great program that i have worked with in the past, shoud provide you with some information.
csd has the best idea.  we do similar things in our local area when we fan out during engineer's week.  
hands on activities are the best since the class can see and touch.  we use 1 x 4 lumber and do the same thing.  the class always ask why the wood bends visibly when loaded one way and not the other.  
a colleague of mine got some large blocks of polystyrene and carved them into blocks suitable for making an arch.  he then got the students to build the arch, and of course it kept falling over.  he then got two students to stand on a block at either end and another to sit on the keystone. it was now stable and carried the weight no bother.  i expect we wouldnt be allowed to do that in the uk now because of health and safety but it was a good demonstration.
another one i like is the demonstration of a cantilever bridge that was used to demonstrate the principle for the forth rail bridge back in the late 1800's.
if you have a flexible footbridge nearby, you could illustrate resonance for them.  first get out there with a metronome and observer or two and walk at different frequencies between about 100 bpm and 130 bpm.  you should be able to zero in on the resonant frequency pretty fast.  show them that the bridge barely moves if you walk 5 bpm below it or above it, but that it vibrates much stronger if you walk at the resonant frequency.  i do this for adults fairly frequently and they're almost always amazed.  point out that a human weighs many, many times less, but can really get it moving.
we had a guy come into our econ class. he seperated us into several different groups. each group got something like 4 peices of paper and then each group got some kind of fastining mechanism such paper clip, tape, string. we were then asked to build a structure. after everyone had completed their structure he would take his clip board and do three swipes through the air to try and see whos structure would blow down do to the wind created by swinging the clip board. the last one standing won some prize..
i use a quick exercise with young children to illustrate design choices.  i ask them to make a bridge from a single sheet of paper.  then i demonstrate that a single sheet of paper is too flexible, until you fold it.  then i explain the designer has to decide how many times to fold it to make it perform best.  he has to understand that you can only fold it into some shapes, because you are only able to make folds so close together and stuff like that.  all in all, it is a fun exercise.  however, it would use up a lot of class time and the kids wouldn't learn much about engineering.  but they may become interested in learning more.
i also do a three day thing with a popsicle stick bridge problem from time to time.  good luck.
perhaps you could convince the school to schedule a field trip.  it could be to a construction site, testing lab, engineering office or fabrication shop etc. and you could help lead the trip.  this would work equally well for middle school or for high school kids
hmm.  bridges aren't very exciting (compared to rocket engines).  when i did my presentation to my son's class, they weren't too excited by my pictures of rockets and spacecraft (ho hum, seen it on tv) ...but then i showed them a ruptured pressure vessel that had failed in test (but i called it a rocket engine, which, it kinda was when it let go...).  they got really interested, and we had a lively discussion of stresses, stress concentrations, thermal effects...  i led them on a bit too, asking "how should the dumb engineer have designed it so it wouldn't break?", then letting them know at the end that the dumb engineer was me.  more discussion of how engineers are always learning, always trying to apply what they know to make things work in the real world, etc.
crumbled bridges and collapsed buildings, tragic though they may be, generate a lot more excitement/interest and provide a much more dramatic and lasting impression of what stress analysis is, and why engineers are important (who else ya gonna blame?