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.
What is this engineering task?
Design and build a device/machine that shows the transfer of energy.
Here are some interesting ideas that I may be thinking of:
Solar Powered Car
Pros: fun, works well, simple
Cons: very common, hard to modify
Solar Powered Charging Bank (No.3)
Pros: very useful, simple, effective
Cons: possibly dangerous, could be more aesthetically pleasing
Solar Powered Fan (No.4)
Pros: simple, easy to make
Cons: hard to modify, situational, unoriginal
Solar Powered Air Heater
Pros: useful in the winter
Cons: requires many materials, may take a long time to make
Electricity Generator (Alternative Video)
Pros: simple mechanism, generates electricity
Cons: possibly not durable, quite complicated
Wednesday: Begin creating the prototype (cut wood, gather materials, etc.)
Friday: Continue and hopefully finish the prototype for testing
Tuesday: Begin final project
Thursday: Finish and test project
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.
What will the polymer be like?
Physical properties of our polymer include:
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.
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.
Lazonby, John. “Ethene (Ethylene).” The Essential Chemical Industry Online, www.essentialchemicalindustry.org/chemicals/ethene.html.
“How Is Nylon Made?” OpenLearn, The Open University, 26 Sept. 2005, www.open.edu/openlearn/science-maths-technology/science/chemistry/how-nylon-made.
“Natural vs. Synthetic Polymers.” Gelfand Center – Carnegie Mellon University, www.cmu.edu/gelfand/education/k12-teachers/polymers/natural-synthetic-polymers/.
“Polyester.” How Products Are Made, www.madehow.com/Volume-2/Polyester.html.