BRONZE

#### Popsicle stick bridge

I will build a bridge using popsicle sticks and school glue that is strong enough to carry a heavy amount of weight.

### Hypothesis

I think if I make a strong base for my bridge then the bridge will hold a lot of weight because the bridge will be stronger. I think the bridge will need 100 popsicle sticks.

### Research

I did research on the internet to see which is the strongest bridge design. I found out that triangles are the strongest shape so I decided to use that shape for my bridge design. Also I found out that it is important to spread out the weights that I put on my bridge because if I put all the weight in one place it will be more likely to break. I also found out that it is important to build the bridge slowly and to wait at least 24 hours for the glue to dry before adding more to the bridge.

### Variables

The controlled varirable is the the builder (Hamza), the popsicle sticks, and the school glue that is used to build the bridge.

The manipulated variable is the weights that I put on top of the bridge.

The responding variable is the strength of the bridge which is measured by seeing at what weight the bridge breaks. For example a strong bridge will break at a big amount of weight but a weak bridge will break at a small amount of weight.

### Procedure

First, I had to look around on YouTube for a good idea, then I decided to do a popsicle stick bridge. Next, I  had to think of designs. I looked on google and on YouTube, and I came up with an idea based on what I reserarched. After I built it, I noticed that it did not work because it took up to many popsicle sticks. After that, I had to make walls but to make them stronger I made it stronger by layering it by 3. Next, I made the roof and the floor 3x. Then, it was time to test it it held 77 pounds. I think that it could hold more but we ran out of weights.

### Observations

During the building process:

I noticed that if the glue did not dry all the way, the popsicle sticks would move when I added another layer. I also noticed that if the popsicle sticks dryed crooked this made the whole bridge weaker because it was not straight which means the next layer would also not be straight. This problem happened a lot because it is easy to move a stick accidently when the glue was not fully dry. Many times I had to go back and take sticks apart and glue them again straight. Also before I decided to add a roof, the bridge was not stable and the sides kept moving. The roof was an important add on even though it was not part of the design when I started.

During the testing process:

It was important to add the weights slowly in order to find out exactly how much weight the bridge would break under. I had to keep track of how much weight I was adding. I had eight 2.5lbs weights, four 5lbs weights, four 7.5lbs weights, and one 7lbs weight so I needed to add carefully. My bridge did not break even though I added all the weights I had which was equal to 77lbs. It did not even bend so I think it could take even more weight.

### Analysis

The bridge was strong because I used a triangle design for the base. It did not bend or break when I put 77lbs on top of it which means that it was strong.

### Conclusion

My bridge was able to hold 77 pounds which is all the weights we had. It did not break because the base was strong since it was made out of triangles. The bridge needed 166 popsicle sticks, which is 66 more than my hypothsis. I was happy that it did not break because it proves my design was good. Also I want to keep my bridge forever as a memory of my first ever science fair.

### Application

This project is important because it teaches about how to build strong structures. You can use this information if you work in engineering or construction. You can even use this information when you are building a tree house.

### Sources Of Error

I think things went wrong when I made the second layer of the walls because I made it in the wrong order. So I had to take it apart and fix it. There was also some trial and error choosing my design. My first one not did not work so I had to find a new design.

### Acknowledgement

I would like to thank my parents for their support and buying me the materials I needed. Also, thanks to my dad for recording my video and my mom for being the audience.