Popsicle Stick Bridge

1,461,991

201

167

Introduction: Popsicle Stick Bridge

About: Ask me questions. I know the answers.

The popsicle stick bridge is a classic science demonstration and competition. Every year many students world-wide build bridges made soley from popsicle sticks and glue, to see which designs can hold the most weight.

We built one, using maybe 140 sticks, give or take a few. Not expecting it to hold much weight, we were surprised by how strong it ended up being! (results in last step)

Step 1: Design Your Bridge

There are many ways to build bridges, both real bridges and popsicle stick bridges. Do some research, be creative, and remember - triangles are strong.
A triangle spreads out weight and is much more stable than a simple rectangle or square support. Be sure to incorporate lots of triangles into your bridge design. More popsicle sticks doesn't necessarily mean a stronger bridge.

In fact, according to the internet, "If there is a single most important shape in engineering, it is the triangle. Unlike a rectangle, a triangle cannot be deformed without changing the length of one of its sides or breaking one of its joints. In fact, one of the simplest ways to strengthen a rectangle is to add supports that form triangles at the rectangle's corners or across its diagonal length. A single support between two diagonal corners greatly strengthens a rectangle by turning it into two triangles."[link]

My design consists of two main bottom supports, and two across the top, and then a lot of triangles across the sides, the top and bottom, and going from the bottom of one side to the top of the other. Very similar to the one in the diagram.

Draw your design on paper, and estimate the number of sticks you will need.
Be creative with your design!

Step 2: Supplies

Very, very simple:

-Popsicle sticks
-Wood glue
-PVC (optional)

Step 3: Constructing

Some things to keep in mind:

A clamp of some sort is a good idea when constructing. I used Tim Andersons method, but bulldog clips work just as well. Clamps are important because most of the popsicle stick aren't flat, so if you don't clamp them when you glue them together your bridge probably won't hold together very well.

Don't pinch your fingers.

Keep your workspace clean! I glued everything on top of a piece of paper, as I have a tendency to get glue everywhere.

Step 4: Start Small

I started by making smaller pieces that would be easier to glue together. I counted out how many I needed and started with that. Once they'd dried just enough to not fall apart, I moved on.

Step 5: Get Bigger...

I glued the smaller pieces together, to create the main supports for the bridge. I then repeated the process and made some slightly shorter pieces for the top.

Step 6: Add Supports

I started with each side of the bridge, keeping them symmetrical, then flipped each side and added more.

Step 7: Add MORE Supports

I added angled supports across the bottom to start with, to hold it together, then across the top.
Keeping in mind the idea that triangles are strong, I added some center supports going across as well as up and down.

Step 8: Finish It Off

I finished it off with some pieces across the top. I'm not sure they add any structural support, but they look good.
I also touched-up on the glue where it was looking scarce, and added more horizontal supports.

Lastly I sanded the top, to make it completely flat so that weight wouldn't be focused on any one point

Step 9: Break It! (Or Try)

This is the last step, obviously.

We decided we'd test the bridge with sand in a bucket. We bought two 60 lb bags of sand, thinking surely my bridge would break under 120 lbs.
It held 120 lbs.
We emptied the sand out, and added 40 lbs of water, then added all the sand back. It still held.

We tried the intern, and it still held.

Two days later we bought another 150 lbs of sand. The bridge finally broke under 205 lbs!

How much does yours weigh?

8 People Made This Project!

Recommendations

  • Hand Tools Only Challenge

    Hand Tools Only Challenge
  • Modify It Speed Challenge

    Modify It Speed Challenge
  • Remix Contest

    Remix Contest

167 Discussions

0
joelvanf
joelvanf

Question 27 days ago on Step 3

Hi, I am participating a popsicle-stick bridge competition in my school. We are limited to using 100 sticks and elmer's school glue (not wood glue). Would this project work with elmer's white school glue? Also, is it more than 100 popsicle sticks?

0
Diycreator123
Diycreator123

4 years ago

Which bridge design do you think is the best to hold to most weight? Or is it rather the complexity of the bridge that holds a lot of weight?

0
allieandrews11
allieandrews11

Reply 6 months ago

well it depends if ur using it for a project or to test weight, A smaller one is more compact, so it can hold more weight, but if its a project, i would use a big bridge :)

0
ltaylor251
ltaylor251

Reply 12 months ago

the big one duh

0
kingwin4lot2410
kingwin4lot2410

Reply 4 years ago

try a combination of different types of bridges.

0
TechieNun
TechieNun

10 months ago

Excellent tutorial- you helped us launch our first ever "Builder Badge" project for 80 Grade 4 and Grade 5 students at our tribal school. This was our first big project for our new Makerspace STEAM program, which we call Kaġapi Oyaƞke. That is the Dakotah language for "we make things here." We used this project to teach the Engineering Process and also leveraged the hands-on learning to address math, science, and even language/English skills and goals. So, thanks for letting us incorporate geometry, measurement, force and simple machines, as well as oral and written language development, collaboration, and problem-solving skills into a great month-long project. Enjoy the pictures. You'll notice that while many student teams incorporated truss bridges, most did their own adaptations to a basic truss design.

Challenges: We had about 80 students doing this project simultaneously (two Grade 4 classes and two Grade 5). We also have a total of 250 pre-kindergarten through Gr.5 students using our Makerspace classroom each week AND the same space is used to teach beginning readers each morning.

Challenge 1: Space! Where to find enough space to store our projects as we created them was a big challenge, particularly since the room is shared by so many each week. Other classes had other projects, too. We quickly ran out of room and some projects had to live in the teacher's car between work sessions. (Note- we're saving some of these finished bridges for our end of the year "Maker Fair" so the storage challenge continues. The only storage left in our classroom is overhead, so we will be hanging them from our ceiling to display and store them for the next several months. We've got new projects each month as students earn a new "badge" for their engineering notebooks.)

Challenge 2:Electric outlets! our room used to be a third grade classroom and there simply are not enough conveniently located electric outlets for our glue guns. We had to set up "gluing stations" by the outlets and teams rotated to use them. We tried extension cords, but too many tripping hazards.

Challenge 3:Keeping track of 20 teams' projects at all stages of creation was a logistical challenge. We ended up using tags on everything... and each tag had to include teacher name/grade/ team name and be placed in the storage area or a box in between sessions. Luckily, nothing got lost!

Our photos (see PDF below) show the various stages of the project. We're also sharing the student lesson materials below.

Overall, the project was a HUGE success. This is our very first year offering activities via a STEAM program, so it turned out to be better than anyone ever imagined. Thanks for the original posting, drinkmorecoffee! You inspired us!

0
PatrickA2
PatrickA2

5 years ago on Introduction

How about using a glue gun for steps 3-5? It dries faster!

0
olivia.galarza
olivia.galarza

Reply 11 months ago

yes it does because you can do the brige faster and it will really work love you

0
AudreyB31
AudreyB31

Reply 4 years ago

But it won't stick as wet as wood glue.

0
Wizard of Everything
Wizard of Everything

Reply 3 years ago

a glue gun will not hold the sticks together for long. elmer's regular school glue and wood glue soak into the wood (sort of) and that makes it stick better than glue from a glue gun. Yeah, that's my boring glue lecture...

0
moo152002
moo152002

Answer 1 year ago

she said 140 sticks

0
olivia.galarza
olivia.galarza

Reply 11 months ago

you need 200 because you might have to re start a lot and you are not going to have a lot so you have to buy at lest 200-900

0
sgonzalez0555
sgonzalez0555

Reply 1 year ago

you could also use less

1
Mahin Mvp
Mahin Mvp

Question 11 months ago

How much stick did you use for this?

0
olivia.galarza
olivia.galarza

Answer 11 months ago

you might have to use 200

0
yitzchakb
yitzchakb

11 months ago on Introduction

when u said in step 8 that u added more horizontal supports, where?