Aidan

My Design Process

To begin, I defined the problem that we needed to solve for this project. We needed to make something that demonstrates energy conversion. Then, I analyzed precedents and used them to inspire my solutions. Next, I reviewed my solutions and determined which one was the most feasible; in my case, it was the air cannon. Then, I constructed the air cannon. Finally, I analyzed the completed air cannon and compared it to my expectations, as well as considering feedback from the users. The feedback and analysis will be used to further my knowledge about design and help me with future products.

Throughout the design cycle, I followed the standard ISB design process closely. I started with defining and inquiring, then moved onto developing and planning, and after that, creating and improving. I actually went back to developing and planning to make a few changes to my blueprints. I found that the time constraints made it difficult to go back and revise the plans. However, the process did result in a successful product.

 

My Product

As shown in the prior post, my product is an air cannon. The air cannon shoots air by using a sheet of plastic propelled by an elastic band. The air is forced down the barrel and comes out of the other end, which is usually pointed at another person. After a second, the air hits the other person. The product demonstrates a conversion of chemical energy (human body) to kinetic energy (moving the elastic back) to elastic energy (stored in the elastic), then, when the elastic is released, to kinetic energy (the air), sound energy, and some excess heat energy in the form of resistance between moving molecules.

 

My Learning

I learned about several new manufacturing techniques, as stated in the previous post:

“During the session, I learned several new techniques and skills. In order to drill holes in the soft plastic bucket, I had to press the surface against a hard piece of wood. To ensure that the screws did not break the plastic tub, washers were needed between the tub and the screw. To soften and smooth the edges of the grip, I originally planned on using sandpaper, but I was introduced to the electric sander and used that instead; the electrical sander was far faster and provided a smoother finish.”

Also, I gained valuable experience about design.

 

Success?

I believe that my product is successful. While it may be ugly and ineffective at times, it is nonetheless a tool that demonstrates energy conversion, from chemical energy to kinetic energy to elastic energy to kinetic energy. The air cannon is able to shoot air up to three meters and was used extensively on Tuesday. Throughout the testing, none of the mechanisms failed on the air cannon. It was always able to shoot air at targets close by. However, there are some problems with the design. For one, the air cannon is extremely inaccurate. Often, it took multiple shots to hit a target. Also, the grip was described as being too wobbly; that problem was quickly remedied with hot glue. Despite the existence of problems within my final prototype, I would still consider it a success.

 

Impacts

For physics teachers, I do believe this product would help them teach energy conversion. An air cannon is quite fun and would draw the attention of students towards the teacher. For younger teenagers and adults, this air cannon would be a fun toy. The consenting and voluntary testers of this product were able to have fun shooting at each other and feeling bubbles of air hit them.

As for the environment, I predict that the product has a pretty neutral environmental impact. Most of the materials used were basically trash; the plastic tubs and sheets were scavenged from the reuse bins and the wood was from a pile of used wood pieces. The screws, elastics, and tape were new, but they made up an insignificant portion of the final product. However, if this product was to be made at an industrial scale with planned improvements, then it would have more impact. While wood is sustainable, its transportation is not. Also, more new materials will be used. However, despite all these problems, manufacture of this product would not have a noticeable impact on the environment.

During our lab sessions, I completed building the air cannon.

To begin, I selected the materials I needed. I found some plastic tubs and plastic sheets in the reusable plastics bin in the design lab; by reusing materials, I was able to reduce my environmental impact and use up old materials within the bins. I was able to procure a roll of elastics from the closets, which I later cut into three strips – two for the cannon, and one as backup.

First, I cut holes in the bottoms of the plastic tubs with a pair of scissors. I marked out the lines I needed to cut with a permanent marker taped onto a compass, then punctured the bottoms with my scissors. Afterwards, I traced out an outline of the grip on a piece of paper and cut it out. I brought that piece into the design lab and used it as a template for my grip. With the help of Mr. Diego, I cut out the grip on a piece of 2cm thick wood, sanded down the grip, drilled holes in the bucket and grip, and screwed them together with long Phillips screws. During the session, I learned several new techniques and skills. In order to drill holes in the soft plastic bucket, I had to press the surface against a hard piece of wood. To ensure that the screws did not break the plastic tub, washers were needed between the tub and the screw. To soften and smooth the edges of the grip, I originally planned on using sandpaper, but I was introduced to the electric sander and used that instead; the electrical sander was far faster and provided a smoother finish.

Next, I extended the barrel using the smaller tub, which was taped on. I realized that my original idea of modular barrel attachments was far too finicky, so I made an attachment using a piece of paper pressure-fitted onto the barrel. This helped decrease the barrel weight and allowed for easier construction of modular attachments.

Finally, I attached the elastics and plastic sheet on the back of the air cannon. I realized the original plastic sheet selected was far too thick, so I found another thinner sheet in the reuse bin. I mostly used duct tape for the attachment process, as it was the most visible type of tape. Any other would have been too hard to spot and would cause a more difficult repair down the line, when the plastic sheet inevitably breaks. Unfortunately, my idea for a handle to pull back the elastics was not feasible as it would cause far too much stress on either the elastic bands or the plastic sheet, or cause an air leak.

 

The air cannon, as its name implies, shot air. While the range was not great, and the amount of air launched was barely enough to knock down some paper, it nonetheless shot air. The air can be felt from over a meter away, but the accuracy can only be described as terrible. Often, only a third of the shots hit, even while aiming in the same direction. It was precise, but not accurate. Also, barrel attachments can be made out of paper and pressure-fitted onto the front. This allows for quick changes to the barrel, but the additional piece in the front often decreased the amount of air coming out and therefore the effectiveness of the air cannon. The grip, on the other hand, was very nice. Nobody complained about its size or shape. The edges were sanded down to prevent them from cutting into the hand, and the grip was slightly angled for better ergonomics.

 

I tested the air cannon on my friends with their consent. Also, Mr. Walton tested it out when he saw me with it.

Much of the feedback were about the accuracy and range. While the air was noticeable from a range up to a few meters, it was hard to aim the cannon. Often, it took multiple attempts just to hit someone at a range of one meter. According to Peter, the best way to aim was to have the target stand still and constantly adjust the direction of the cannon until the air hit. Henry also mentioned that the grip moved during firing. While durability was not a concern, the shaking barrel was one of the culprits behind the inaccuracy. In a somewhat successful attempt to solve the issue, I added hot glue between the barrel and the handle. Mr. Walton thought the duct tape was a bit ugly and detrimental to the aesthetics.

 

Given the opportunity, I would make many changes to the current design. While reusing plastic tubs is environmentally friendly, a 3D printed barrel would be far more durable and versatile. I would add some reinforcements in the back so the barrel would not squish as much during firing. The current barrel attachment system is subpar; a 3D printed barrel would allow for a system similar to the original design plan. I would keep the current wooden grip design, as it felt satisfying and sturdy. Finally, instead of using random, small strips of duct tape, I would use larger pieces placed consistently around the back so it appears somewhat like a pattern while still keeping the advantages of duct tape.