This is the point where you get knee deep in engineering. Our idea to make a soil permeability test vessel in which water flow is measured by an ultrasonic sensor attached to the basic stamp. Early last week we decided on going with this idea, and felt we were well on our way to solution. I was ready to start building our first or second idea without even having a scale drawing. My reaction was to act as a tinkerer, but Dr. Iskander, Russ, Eduardo, and Andrew made sure we acted as engineers. An engineer must plan and discuss the function of every single part of the plan. This reminds me of my former career as a photographer. When you want to make an important image, you are responsible for every element in that frame. Our rough sketches gave us a focal point for our discussion.
We decided at that time to make the soil container out of acrylic plastic. We started to do the math to estimate the supply costs. We were going to have to spend $300 on plastic alone. This ate up all of our budget. We searched a few dusty corners in the basement, but did not find the right materials.
Dr. Iskander must approve our design before we build. He pushed us to really work the design harder. We came up with a less expensive option. Rather than use acrylic plastic, we would make the soil vessel out of flexible hose supported by plywood. We reduced the cost by 33%. We were confident that this design was it. We needed to make an accurate drawing, so it was time to learn SketchUp.
We spent most of the morning learning the ropes, but by lunch Russ and I were novice drafters. Our design team met to look at the above design. We knew the system would work, but there were some weaknesses. Our design was now two feet tall with a 1 litre bottle of water at the top. Would a this be a good fit for seven year olds? Did it look like a something a scientist would use? Time to break out the notebooks again. We started to flush out a design with our original, more expensive material.
Back to the acrylic plastic tubing.
I think Dr. Iskander drew the above design. Russ made this incredible drawing in SketchUp.
soil permeability test apparatus
I broke out the pencil.
Soil permeability test aparatus
I am having a blast designing our own piece of lab equipment. I forgot to mention the machinists that are helping us. Sebastian and Alex have been helping us understand what is best for machining. They will be fabricating our design.
This process is incredibly empowering. My students need this experience. That brings me to wonderful class I took last semester. Through a state grant I was able to take a free class called Elementary Science and Engineering I — EDCE 7502N at CCNY. This class is taught by Dr. David Crismond. He is a pioneer of design in the classroom. You can learn more about his work at the DITC Site. One of the projects we did in his class was to build a model skyscraper. He modeled this activity for us to repeat it with our students. We followed an identical design process with the student activity and the real engineering research at NYU Poly. We had a limited budget to buy materials and land to build our skyscraper. We had to submit multiple detailed designs and budgets in order to receive a building permit from the building inspector, Dr. Crismond. The building had to be as tall as possible and capable of holding a 16oz bottle at the top while undergoing a tilt test. Here is our teams model:
Team Uno's Skyscraper
Our team crushed the competition. Doesn’t our building work well in the New York skyline?
We have a two small revisions to do on our soil apparatus, but Dr. Iskander granted the building permit on Thursday. Russ placed the acrylic order on Friday. We then began planning for our second project, which is also over budget. The building inspector told us, “An engineer can do for a buck what any darn fool can do for two bucks”. We will be back to the drawing board tomorrow morning.
I will leave you with a sneak peak of two of the things we are working on this week.
What is hiding in the beaker? This soil will become transparent. Tune in Tuesday.
Our garden project needs more micro-controller horsepower than the BS2.
Have a magnificent Monday my good people!
This work is supported in part by the National Science Foundation under a Research Experience for Teachers (RET) Site grant EEC-0807286. We thank the Mechatronics Lab and the Soil Mechanics Lab for hosting us during our summer research program.