This bridge building activity can be a lot of fun
and it can inspire the engineer inside your young bridge designer.
You and your young engineer get to decide how you want to build the bridge
with certain material and requirements the materials list is in the magazine
article
the requirements that the bridge use only be available material
and that the bridge be five popsicle sticks long the rest is up to you and your
young engineer
how many sticks to use, how many levels to the bridge, how to fasten the parts
those are all decisions for you two to make. We also assign a value to each
part so you can factor in cost
which every engineer needs to do in the real world. In the end, you'll see how
much your bridge can hold before collapsing.
we'll give you a formula to rate your bridge based on the materials you used to
construct the bridge
and how much weight it was able to bear. Before we start building
here are some real engineering concepts to keep in mind. We're here today
to build your own trust this is a program that came out of the Xplore
summer workshop that we do at the University of Michigan
and it's also featured in the Michigan Engineer magazine where all the materials
that we're using here today are listed.
But before we get started I wanted to talk a little in terms in truss bridges.
Do you know what types of shapes trusses are made out of?
Triangles is a good guess. What happens if you push that square.
That's going to fall over right?
So if you make a truss bridge out of squares that's not gonna be very stable
and it's actually eventually going to fall down when you put it
some load on top of it or a car drives over it.
so as we mentioned you gonna wanna try to make you trust bridge at a train
girls
we can't think also in terms of you trust bridge
some the forces that are occurring have you heard anything called pension
attention is essentially a few Paul
a prior which causes the squares here to increase in size rain
now we have compression we're gonna push
which causes the squares to you shrink
yes
so when we have a bridge the bridge actually set like this
in a bridge tense a smile right so the squares on the bottom
increase net scores on a top
decrease so means that we have tension on the bottom in compression on top
the sticks they are using you can take these tension and compression forces
see you typical bridge an example the bridge will work
something like this and we can do this using
38 popsicle sticks 11 both
33 knots and then for rubber bands
you can use it to build your own truss bridge that we're gonna test
now the one thing with the truss bridge it's not just the materials they use
each material in the car
so we want to look at how much we bridge holds versus how much a bridge actually
catherine see how you do in terms that
and you go ahead and if you have any questions it more than happy to
entertain you
so one thing to keep in mind is that you probably wanna put
and not on the inside and then it
and not on either side the other side Latrice
up to keep it Stadium on strong
in your bridge should be five members
across the bottom interns to make sure it has a right wing
okay you now it build one side prayers
so put all the pieces on don't put any notes on
initially and then put all in knots on for the one side
and start working on a second I because then you'll know that but with that
second side supposed to look like
you come online yet 30
doing a great job very
meeting
now have fun somewhere came in that time
yeah time-consuming grasp
thing
and then one see it the whole side pleaded and other nuts on the one side
you want to do is put another set a nuts on
a lesson and for the second side to sit on
you just wanna put down far enough that all the members
it with the in you'll be able to get a a second night on
on the top problem and once you have
both sides Nishida I wanna make sure you take in everything up
santini use a rubber bands when you made your bread you can rent and I get a
refund
thank you
had in order to test your bridge you need to suspended between two tables
you also need a way to hook a bucket under the bridge
a small black upward with and I hope can work now is a good time to take pictures
on your branch
it won't be the same after the tests you wanna go ahead and fill the bucket
in the sand now some people and their filling a bucket list and think that
they've
artfully works better so you look at the top
he can the mister in its worth a little
moon I think your bridges done
so we can do now is we're gonna wait and see
and see how much weekday here bridges evil whole
means 24.47
pound reagan newbridge past twenty one thousand eight hundred and sixty dollars
money
so your bridge quality score
which is this your way home times a thousand divided by a bridge past
live gained 1.12 anything over one we consider a very good
say you had a very good grids designs and congratulations
good luck to you and your young engineer this activity was adapted from
I'm connects explore engineering summer camp you can learn more
at engine that UMich that EDU
codes a really come a long way since
some major as place the 1994 Northridge earthquake the 1995 Kobe earthquake
both really cuz the look at how we design steel structures