1. By Savannah and Sophie Block 5
Design Brief

2. Objectives Statement of Inquiry: How do design limitations
encourage creativity.?
What is the objective?
The objective of this project is to make the strongest
bridge with 75 popsicle sticks, 3 sticks of glue, and a
partner. The group’s bridge that holds the most weight
wins.
Global Context:
Scientific and technical innovation
Related and key concepts:
Development and resources
Bridge Design Requirements:
Minimum Span 30cm
Minimum 1 popsicle stick width
Maximum 20 cm superstructure
Maximum 20 cm substructure
Maximum 75 popsicle sticks
Maximum 3 hot glue sticks

3. Inquiry and Analysis Triangles are very strong shapes
Arch bridges are the strongest type of bridge
The longer the span of the bridge the less weight it holds
Stone slabs are a very strong material for short bridges
Commonly used materials are metal, wood, and stone
Triangles are one of the strongest shapes there are
because when a load is applied to the apex of the triangle,
it evenly distributes the weight down the sides of the
triangle. For example, if there is one kilogram of weight
applied to the apex of the triangle, then 0.5 kg would be
distributed down the two sides of the triangle. Resulting
in less compressive force and no damage to the structure.

4. Inquiry and Analysis : Types Of Forces
Type of force
What is it?
Compression
A force that pushes together on opposite sides
Tension
A force that pulls from either side
Torsion
A force that twists
Deflection
The act or force of being deflected

5. Developing Ideas - Designs And Sketches
We decided to do our version
of the Pratt bridge. We thought
it was the strongest structure
because it has lots of triangles
and the popsicle sticks were
dispersed efficiently and evenly.

6. Creation Process
To start our bridge we needed a strong foundation. We stacked 2 layers of popsicle sticks to make it that much stronger.
To make the bridge hold more weight we put the popsicle sticks vertically instead of horizontally. If we did lay the sticks horizontally, they would be very flimsy.
After we made the base,
we started to construct
the superstructure.

7. Waddell A Truss
Pros
Cons
Environmentally friendly
Heavy
Can be built anywhere
Takes up a lot of space
Easily constructed
We didn’t choose this bridge because our popsicle sticks did not allow us to make a
Tall beam across, that was sturdy as well. It would’ve taken more popsicle sticks then
We were supplied with.

8. Camel back
Pros
Cons
Evenly distributes weight
Takes up too much space
Wastes materials
Heavy Weight
We decided not to choose this design because it would use too many popsicle sticks and
judging by the chart above, there are more pros than cons. It would be very difficult to
build this structure because it’s very big and the top popsicle sticks would have to be
glued at just the right angle.

9. Arch bridge
Pros
Cons
Resistant to compression forces
Span is limited
Can be made of many materials
Build time is lengthy
Becomes stronger over time
Can crack easily
We decided not to choose this bridge because it would take up too many popsicle
sticks and it would be hard for us to make the span 30cm. It would also be very
difficult for us to construct the round part of the bridge.

10. Pratt Bridge
Pros
Cons
Simple design
Less stable when it comes to vertical loads
Cost effective structure
Cannot hold greater loads with longer spans
Strong history of short span success
We decided to build this design, because it’s a very strong structure with a simple but effective design. It was designed with lots of triangles so the structure will divide the force of the weights nicely.

11. Team Goals Our goals: Make a sturdy bridge Hold at least 70 lbs
Use class time efficiently
Even out the tasks for the projects
How we’ll achieve these goals:
Work hard during class and ignore distractions
Plan out our bridge design properly

12. Evaluation – Testing day!
We thought that our bridge would hold around 70 pounds of weight. So we started with 5 pound weights and gradually added more.
We decided to put our bridge upside down because
it was stronger that way.
The base we made included
5 layers of popsicle sticks.
Resulting in that the top truss chord
being the strongest part of the bridge.

13. Result
The result of testing concluded with our bridge holding 70 pounds. We tied for first in our class.

14. Evaluation
Our bridge broke right down the middle. This was because there was the most compression force pushing where the chain was suspended.
How could we avoid this problem?
We could’ve avoided this problem by
adding morePopsicle sticks for even more
support. We also could’ve designed our
bridge to distribute out the load more
evenly.