Define the Problem
We made a Gantt Chart and divided responsibilities so that we could have a formal plan to tackle the project. We allotted time for certain activities so that we would not fall behind and we assigned roles so that both team members would feel obliged to participate and take ownership rather than only one doing all of the work.
Gantt Chart
We were able to have an extra day, which we used to rebuild our prototype and test it.
Team Responsibilities
Design Brief
Generate Concepts
Brainstorm (materials): old t-shirt, cotton, screen roll, coffee filter, cloth, sand, gauze, activated carbon, aquarium gravel, foam
Design 1
|
Design 2
|
Design 3
|
Existing Solutions:
Pros: The gradience of pebbles to sand should allow for bigger parts to be filtered out first, with smaller parts following; the activated carbon should cleanse the water before it reaches the paper towel, where it will be cleaned to the greatest extent; the materials are cheap and easy to find (except maybe the carbon); it seems as if water would pass through fairly quickly
Cons: It doesn't seem like it would be very reusable, the paper towel would eventually start to fall apart and the water may even be able to pass between the sides of the bottle and the paper towel after extended use https://www.sunrisespecialty.com/how-to-make-water-filter |
Pros: It probably "wood" work :) because trees are naturally able to move water through their trunks, and they move it against gravity; it is also made of only a few parts than can be easily carried in one's pocket
Cons: Obviously, these components are pretty specific, and there could be leaks if it is not fastened properly; this filter also doesn't have a very large capacity and it would probably take a long time to filter a lot of water https://www.sunrisespecialty.com/how-to-make-water-filter |
Pros: It's eco-friendly because it doesn't use as much plastic; it can be used in emergency situations; the charcoal at the bottom filters out chlorine; it looks like it can be reused multiple times except for the cotton and the charcoal
Cons: It can take some time to filter out the water; it might need multiple filters in order to completely filter out all the dirt and chemicals; the charcoal and cotton would probably need to be replaced after a certain amount of time or it would be ineffective waterfiltermag.com |
Preemptive Materials Testing (NTUs):
-Coffee filter: 18.1
-Cloth & Coffee filter: 70
-Activated carbon & Sand: 180
-Screen roll & Coffee filter: 70
-Sand & Coffee filter: 330
-Gauze: 140
-Cotton & Coffee filter: 7.7
-Paper towel: 40
The cotton and the coffee filter seem to work the best, but that is why these components cannot be major parts of our design. We thought that by layering these materials in a certain order, we could ultimately filter the water the best. For instance, placing sand on top would filter out the bigger parts while the screen and cloth would help remove smaller parts, and finally the cotton and coffee filter would be at the bottom to filter the very tiny pieces of dirt.
-Coffee filter: 18.1
-Cloth & Coffee filter: 70
-Activated carbon & Sand: 180
-Screen roll & Coffee filter: 70
-Sand & Coffee filter: 330
-Gauze: 140
-Cotton & Coffee filter: 7.7
-Paper towel: 40
The cotton and the coffee filter seem to work the best, but that is why these components cannot be major parts of our design. We thought that by layering these materials in a certain order, we could ultimately filter the water the best. For instance, placing sand on top would filter out the bigger parts while the screen and cloth would help remove smaller parts, and finally the cotton and coffee filter would be at the bottom to filter the very tiny pieces of dirt.
We went with our first design because, even though it had more components, we thought that the incorporation of cotton as our main component would be a big help in filtering out the dirty water because after testing it, cotton and the coffee filter performed extraordinarily well with the result of 7.7 NTUs. The screen roll and cloth also performed decently with 70 NTUs, and we thought that the aquarium gravel at the top with the sand right below it would filter out the bigger components.
Develop the Solution
Final Design Sketch
Construct and Test the Prototype
Result: 170 NTUs
Evaluate Results: 170 NTUs is way too high, we need to get this number down to at least around 20 NTUs; the filter also got really dirty and didn't seem like it could be reused
Summary: With the unavailability of cotton and gauze, cotton being a main part of our design, our first prototype failed miserably and we decided to try again by making changes such as bringing in cotton balls and using a bigger and smoother bottle for ease of construction.
Improved Solution:
Results: Test: 25 NTUs, 50 NTUs Final: 3:41 ---> 22 NTUs
Our filter was the worst in class, but it performed better than expected considering the preliminary tests. In addition to the high NTU value, our filter was also relatively slow. To make the water cleaner we could have used better coffee filters or we could have not followed the rules and made cotton a main component. To address the time issue, we could have found a better alternative to paper towels or activated carbon, because both components seemed to absorb the water.
Evaluate the Solution
Summary of revisions: We used 2 coffee filters as planned, this time with a bigger bottle so that the construction was easier; Alexis brought in cotton balls (the cotton balls that everyone else used as a major component in order to make their winning designs) from home so that we were able to add cotton on top of the coffee filters. We then used two sheets of cloth and on top of that we had two layers of paper towels so that we could include a unique material. Then we placed a screen on top of the paper towels and finally some activated carbon. We decided to not include the sand or aquarium rocks because they seemed to make the water murkier. We tested paper towels and they seemed to work well so we decided to use them in our improved design. Of course there are still improvements that could have been made with more time, but our filter satisfied most of the design criteria other than the most important part: under 5 NTUs. Our filter was probably too slow but we did learn that it was definitely reusable, and it even seemed to improve with use. The time issue would also improve with use, as the paper towels and cotton balls would become saturated and water would more easily pass through.
Reflection
I think that this project was one of the worst that I've experienced, mainly because I was not able to be in the classroom. Alexis and I were able to communicate well, especially because she had AirPods so I didn't have to shout over other kids to be heard, although sometimes I felt like I couldn't help in any way or I couldn't see what was going on. It was also annoying, and in a way disturbing, that a class of engineers was unable to be conscientious of their use of materials. I felt helpless to the fact that most kids in the class were testing materials in lieu of using them in their final design without realizing that at the same time they were running out of these very materials as they just threw them away after using them only once. It is sort of ironic that we just finished talking about sustainable energy use and yet we have this problem. It's also a good example of a tragedy of the commons, where everyone only thinks about themselves without considering the impact of their actions on the entire supply of materials, and in the end, everyone loses. Luckily, Alexis was able to bring in her own cotton balls, but of course, everyone else decided to use her cotton balls because they still wanted to create the best filter, and they didn't bring in materials of their own. I think that Alexis and I should be proud of our design because we did follow the constraints, as we did not make cotton the focus of our filter and we only used two coffee filters. Instead we tried to use at least one unique material (that could be either the screen or the paper towels) and our design proved to be reusable. We worked well as a team, mostly because we know each other well and we were able to communicate well. Previously, I thought that a filter with a top layer of rocks on top of sand would work pretty well, as long as the layers below consisted of materials that could better filter the water. I learned, however, that it seems as if the rocks and sand actually make the water dirtier, but this could also be because our original design did not include cotton or gauze, as we did not have access to these materials at the time. I think that if I were to do this again then I would want to be in class and I would like to do more research on possible components or perhaps more research on the components of industrial water filters. The things that I though would work, from minimal research, did not really turn out how I had expected, so maybe testing some different materials would lead to better results. In the future, I think that it would be a good idea to require students to bring in materials, or make sure that they are aware of their use of materials. Then again, maybe it is a good lesson on resourcefulness, but that is only of the students learn from their mistakes and don't continue to take the same actions.