Science Fair ProjectLondon Bridges Falling DownKate Howard and Kira Koziak
Statement of ProblemWhich Truss Design supports the
most weight, the Warren or the Howe?
Project OverviewFor our project we built bridges
out of balsa wood in two designs, The Warren Truss or the Howe Truss. Then we tested them by hanging a bucket from them and measuring in pounds how much water it held.
ResearchThe Warren Truss is the most
used design
Variables Independent- the truss design
Dependent- weight each truss holds
Constants- glue, bucket, wood, bucket securer, type of sand, spot where we hang it, length of bucket to ground, chain, type of styrofoam, person who pours sand
Control- Warren Truss. This is logical because it is the most used truss design.
HypothesisThe Warren Truss will hold the
most weight because it distributes the weight more evenly than the Howe Truss.
MaterialsBalsa wood60cmx60cm block of Styrofoam4572cm of Plastic Wrap(150sq ft)Superglue gel1 piece of graph paperBlock and chainExacto knifeLarge bucketApprox. 10lbs of water1 pen or pencilTruss designs (1 Warren and 1 Howe)2 pairs of safety goggles
Procedure1. Gather supplies2. Wrap the 62cm x 60cm block of Styrofoam completely in plastic wrap with
large sheet of graph paper under the plastic wrap. 3. Draw a Howe design of one piece and a Warren design of another. These will
be what you use as a guide so all of your bridges will be the exact same size.4. Build three of the Warren Trust designs. Make sure to leave a big enough hole
at the top to fit a chain through but small enough to hold the block of wood5. Build three of the Howe Trust designs. Make sure to leave a big enough hole at
the top to fit a chain through but small enough to hold the block of wood 6. Break one trust by laying it across two tables and hanging the chain with the
block of wood from it. Hang the bucket from the chain and slowly pour sand into the bucket.
7. Once the trust breaks weight how much sand the trust held and record observations and chart.
8. Repeat steps 6 and 7 for all five other trusts. 9. Graph all trials 10. Find the average of Warren Trust and average of Howe Trust11. Graph averages12. Compare and contrast
Procedure
Photos
Data and Observations
Category 1
Category 2
0 1 2 3 4 5 6 7 8 9 10WEIGHT HELD IN POUNDS
TRUSS TYPE
RED- TRIAL 1
YELLOW- TRIAL 2
BLUE- TRIAL 3
WARREN
HOWE
ConclusionThe Truss that held the most
weight on average was the Howe Truss. The Howe Truss’ average weight held was 8.27lbs and the Warren Truss’ average weight held was 7.13lbs.
Possible Experiment ErrorsSome possible experiment errors
were gluing and it was hard to monitor how they were being built so it was hard to build each one the exact same way.
Applications and RecommendationsI would recommend that other
people monitor how they build the bridges so that each bridge can be exactly like the others
Works Cited The Toothpick Bridge - Design and Build Strong
Toothpick Bridges. Web. <http://www.toothpickdesign.com/trusstoothpickbridges.htm>.