This is my final product. The picture and the video already appeared in the previous blog post, but they are presented again for convenience. This model is able to adequately convert elastic potential energy into kinetic energy to power a propeller. However, it does not work due to the high mass of the whole model. The kinetic energy generated from the rubber band releasing its elastic tension was not enough to power this model. Occasionally, with the right conditions, the propeller will move the car a few centimeters forward, but this process is not stable and makes this rubber band-powered car nowhere near its optimal functionality.
Of course, when building this model, some risks had to be taken, as the original design (idea taken from a YouTube video) was built out of a lightweight plastic bottle and a bottle cap to hold the propeller in place. Some creativity was required to find a way to hold the propeller in place, determine an optimal length and width to accommodate the wheel axles and rubber band length, etc. In this case, the risks did not resolve as they should have, making the design not work. However, I spent a good amount of effort into this project and I was still able to explain the conversion of energy by explaining the balance between mass and kinetic energy.
These are the materials that I gathered (from the first class). I will be using these materials to create my prototype. My original work plan was to use wood, but I believed that wood would be too heavy and time-consuming to work with, so I substituted cardboard for it instead.
As this is from the first work period, I do not have much to reflect on, but even if my design does not work, I hope that I can learn something from this project.
Using the materials that I cut and picked up from the first class, I started to build my prototype car. I met some problems, e.g. the propeller was situated too low to spin without hitting the ground, so I had to come up with creative solutions that changed my plan a little as I was not expecting these problems when I created the plan. Unfortunately, I do not have a test video of my final prototype, but the car worked – except that it was too heavy to be moved by the propeller.
Here is a photo of the finished prototype design. More rubber bands can be hooked onto the paper clip if necessary. I did not pay much attention to aesthetics, as this is a prototype and I had to see if my design worked.
The third and fourth classes were dedicated to building my final project. Because the propeller seemed to be too weak to push such a heavy object forward, I attempted to counter this problem by using a bigger propeller. I also used a smaller and more compact design to reduce weight. Some of the materials from the prototype were recycled for this design, some were given away to other people, and some were scrapped to be used again. I used white cardboard, as it looks brighter and complements the black wheels + propeller better.
This is a downloadable video of the final prototype in action (spoiler alert: it doesn’t work). The final prototype is quite unstable, but at least sometimes it moves a little. The last blog post will cover more of the reflection on this final design.
My goal for the end of the semester is to improve my dexterity (i.e. playing speed and tonguing). The excerpt is from the piece that I believe is the most useful for improving on, Minimalist Dances (bars 194-204).
There are plenty of exercises online that can help me practice my playing speed – I will practice every day optimally, and switch exercises/etudes every week or every few days.
The Capstone Project is a trimester-long project where students choose an issue that affects China and/or the world. My choice was renewable energy, from which I learned that the problem of fossil fuels is not an easy problem to solve and why clean energy is hard to come by. This problem is one that not many know of and my opinions have certainly changed from reading various articles explaining the true danger of switching to renewable power. Many people, including me in the past, believe(d) that reducing air pollution and fossil fuel usage was as simple as using solar or wind power. However, I have found that this is not the case.
One thing I would recommend to next year’s G8 students is to find research that will actually be relevant to the topic. When writing the essay, try not to do any additional research, because it makes citing sources a lot harder. Be creative when making the video; it will make for a much more enjoyable project.
The catapult project is a creative and different way of displaying our knowledge of quadratic equations. Each team was to build a catapult that is capable of holding and shooting a table tennis ball in an arc. After the process of building, the shot of the catapult was filmed and put into Logger Pro, which gave a quadratic equation that roughly matches the arc of the table tennis ball. The purpose of this project is to solidify our understanding of quadratics and to know how quadratic equations can be applied to real-world situations.
My team (Angela and I) decided to use this catapult’s design. It is simple to build, while not requiring any wood cutting or complex structures.
One problem we had with this design was that the ball would not shoot upwards in an arc, but would shoot sideways. This caused the ball to be too low. To deal with this problem, a pencil was placed above the component that holds the ball when it is pulled back. With the pencil, the part of the catapult that launches the ball would stop before moving its maximum distance, making the ball fly at a higher angle.
I believe the hardest part of this project was evaluating whether the catapult’s design would be strong enough or if it needed modifications. Building and testing the catapult is not hard, but the planning and the modifying process may take a long time and/or be difficult because it involves a lot of trial and error.
My understanding of quadratic equations improved as I learned how quadratics are used in a real situation and how they can be used with different axes to represent different types of data (for example, height vs. time and height vs. distance are different and used in different contexts).
I believe the design process is important when doing a project like this, but the mathematical understanding of the catapults is the most important, especially in a math class. The unit of quadratics is possibly the most important of Algebra I, and there is no better way of showing understanding than in a real-life situation.
By mixing Super Slime and Boogers together, we made our first prototype called “Super Booger”. It was very stretchy and gel-like without being too sticky or wet. It seemed perfect for our design goal. One thing I would change was that even though it seemed simple to make with just two base polymers, it took a lot of extra materials to perfect and adjust it to how we wanted. This polymer was unique but hard to create.
Our second prototype called “Super Everything” attempted to combine Gloop, Boogers, Super Slime and Oobleck together. The result was stretchy and gel-like just like our first prototype, but it was sticky and was very wet as we had added a large amount of water for the Oobleck. In the end, it was too sticky and hard to clean to be a polymer that was meant to keep things together without damaging them.
We performed a few tests on Prototype #1 to see if it was really that strong. It was poked slowly and quickly to see if any of it would stick to a surface. The polymer only left the object wet for a few seconds and none of it was displaced. It was stretched extremely long and held in the air at the sides to see how long it could go without breaking. It stretched for over ten meters and did not collapse to pressure. It was dropped at around a one-meter height and bounced instead of splattering across the table.
Our first prototype is the most effective at performing its intended purpose. Since our goal was to create a polymer that holds things together like a piece of string or an elastic band, Prototype #1 proved to be much stronger. Both prototypes were fairly stretchy and gel-like, although the first prototype was much less slime-like and held its form better. Its non-sticky and dry properties made it superior to its alternative, due to the polymer’s ease of use and cleanliness.
If we had more time allocated for us to work on this product, I would try to find a way to make it less wet, as even though it left no stains or damage, it visibly left a mark when placed on the table.
I believe we did fairly well in these steps of the design process; however, two prototypes may not be enough. If we had more time to create more than two different types of polymers, we would have had a more complete and finalized product. Our prototypes should have also been tested and observed more, to see the strengths and weaknesses of each design.
Here are the steps to create our polymer, “Untangled Slime”:
Measure 55g of glue in a cup.
Measure 40mL of PVA solution in a graduated cylinder and pour into a separate cup.
Measure 40mL of laundry starch in a graduated cylinder.
Measure 8mL of borax solution in another graduated cylinder.
Pour the borax into the cup with the PVA solution and stir for a few minutes while mixing the laundry starch with the glue, stirring both simultaneously.
Combine the two polymers together in a large beaker, adding around 5mL of borax to the mixture if necessary to help the two polymers mix.
Pick up the mixture and mold it until the two polymers have visually combined into one.
The polymer should not break very easily when stretched very wide or pressed down with a moderate amount of force. Otherwise, it would not be useful to hold anything together.
Not sticky and not wet
No one likes an incredibly sticky or wet slime. It gets everywhere – on clothing, on desks, on the skin – and is hard to get off. A sticky polymer would not be useful for our design either.
A bouncy polymer will feel less slimy and will stick to fewer surfaces. It will also be less likely to break when dropped. All of these characteristics are ideal for a moldable rope-like design that we are going for.
Who doesn’t like something that looks good?
How are we going to build our prototypes?
Created using draw.io
How will the polymer be tested?
After the creating stage is completed, the polymer will be stuck to surfaces, wrapped around small objects, pushed on, poked, molded, and stretched into a long, thin strand. It will also be left out overnight to dry. These tests are to ensure that the polymer fulfills (or does not fulfill) the desired physical properties. A good prototype should be maintaining these properties.
The polymer that I (we) want to design is for a very specific situation but could potentially be helpful.
It will be similar to this design, protecting the wire from being broken and also holding it together to prevent the earbuds from tangling. The targeted audience is, if not obvious enough, people who use earbuds, namely people who experience the problem of untangling earbuds that have unfortunately been coiled together several times in their pockets.
This polymer will hold earbuds in a neat position, making them a lot easier to unravel.
The relative lack of stickiness in Gloop makes any polymer with this characteristic ideal for attaching to items. I also liked the simplicity of Super Slime, which consists of only two materials. Adding more of one material would make the substance more watery and less solid, adding more of the other would make it thicker and drip less liquid.