the great 9th grade boat project
For this project, we had to take our newly found knowledge of buoyancy and gravity's affect on floating objects, and make our own boats to float out onto the bay. But here's the catch,...... our boats could ONLY be made out of cardboard, packing tape and plastic bottles. NO rafts. All of the 9th grade classes had to calculate the best flotation and aerodynamics and then apply it to the final boat structure. In the end, everyone floated, it was when the card board got wet or too much water got in that the boat sunk. For my group, I jumped out of my boat, putting to much pressure on one little section of the boat and causing it to overflow with water. Oops :) The last thing we had to achieve was to pick a topic and have a whole demonstration of our choice on that topic. My group, Rob, Peyten and I, chose Buoyancy; Negative, Neutral, and Positive. We brought in a fish, named McLovin, and he demonstrated all three of the stages of Buoyancy.
Question one:
At first our design was good. We had a rectangular base with a triangle at the front for a little bit of added aerodynamics. It floated and held ALL of the bottles even though it was one of the smallest boats. But our actual boat, ended up being just rectangular and absolutely huge. Because it was so big, the buoyant force could easily hold it on top of the water and all the layers of tape we used also helped out alot, but without the triangle tip, our sense of direction was sad and we spun in circles a lot. or maybe that was because it was just so big. Either way we couldn’t really make it anywhere. I would definitely make the boat smaller so we could actually get somewhere and maybe add a few more layers of cardboard, but in the end I was actually very proud of my boat. It floated even when people told my group that it wasn’t going to make it an inch out into the water and ours turned out to be one of the best floating boats. Only a little tiny bit of water got in when Peyten jump in before we launched off and the rest was when I jumped into the water and took it down with me.
Question two:
Lea’s boat was just LAYERED in tape like there were no gaps what-so-ever and even though mine had quite a few layers of tape, I would definitely make it smaller so more tape could be layered on my boat as well. I also like, Nicholas, Diana and Panda’s idea. It was small, slender and had a ton of buoyant force. I bet if you added the sides together it had almost as much buoyant force as my boat so that’s kind of brilliant. I would actually like to make it so that balance is easier, maybe just a little bit of flat bottom instead of a triangular prism. The last thing I would add to my boat, that several others had would have to be seats...... because our boat did cave when i jumped out. It looked like it was eating Peyten and Panda alive! With seats it probably wouldn’t have folded as easily.
Question three:
Archimedes Principle always makes me laugh. I love the story of how he notice the water spill out of his tub and then decided run down the streets of Greece, naked. This principle tells us that, with the right amount of buoyant force applied, anything can float, whether it be a piece of wood or a piece of steel or a cardboard boat. Because my boat’s base was so big, a huge amount of water was pushing back up onto my boat making it easy to float. But cardboard floats no matter what, its how you make a steel boat float that’s amazing. By messing with the average density (whether a random chunk of something is able to float or not) you can spread it out so there is more buoyant force, and press air bubbles into it so that it is less dense. We tried to take this rule and apply it to our boat, making it too big to row but float with ease :)
McLovin
![Picture](/uploads/1/6/5/9/16591066/6880748.jpeg)
To the left, you see a picture of a fish.... a Beta to be specific. Sadly, our Beta, McLovin, never had any photographs taken of him so this fish, McLovin Junior, or MJ, must take his place. MJ, along with other fish, has a special pocket of air inside himself that he can compress and cause to grow by taking in the oxygen within the water. When, the pocket shrinks, air is let out of his body and causes him to become DENSER or NEGATIVELY BUOYANT and sink. When he takes in oxygen, the air pocket expands and, since air is less dense than water, he begins to float up or become POSITIVELY BUOYANT. NEUTRAL BUOYANCY, if you haven't already guessed, is when he floats somewhere in the middle, not sinking, not floating, just right smack in between the two.
Reflection
In the end, my group and I worked very hard on this project. Even though our boat look terrible, like it would sink the second it hit the water, we floated perfectly. Didn't sink until I jumped out! Our boat was probably the biggest one and took forever to tape. Not to mention we taped it over about three times. The amount of surface area made it INCREDIBLY frustrating to cover. When you look at my work personally, I feel that I was very productive and got the work done. I had my doubts. We didn't follow our original design and it looked horrific, everyone was telling us we were going to fail. But in the end, our boat floated perfectly with very little water getting in AND had three people in it where as other boats only had one or two. I was proud of the work I had done.