It is hard to believe next week will be our last week in the lab. This week was very positive because the controller is now working well enough to hand off to Dr. Bifano and to be useful to him in his class.
Major software change
We started the week trying to debug a problem with the transformation from a matrix of the desired image to the slopes that will be used to drive the controller. It requires scaling and shifting and finding the gradient and it mostly worked but we couldn't figure out why the resulting slopes didn't seem centered inside the pupil. The scaling and shifting was not just a matter of multiplying and adding. Instead we had to remap it to a new grid depending the lenslet positions of the wavefront sensor. We found some things to fix and then found the most significant problem. Sometimes the software referred to matrices with x's and y's and sometimes with rows and columns. The problem was that it was not consistent on which went with which. These variables are all throughout the code. So, we decided to change everything to rows and columns. It was a massive change that required modifying all of the software at once. Luckily for us, this change was coincident with Dr. Bifano being free to work with us for nearly two solid days. The three of us went through the code together line by line start to finish. Now that we're done it really works great.
A new aberration glass
We found that our motor still turned our aberration wheel too fast for the controller to be able to keep up with removing the distortion from the wavefront. We changed the code to make it move a little, and then wait for the controller to fix the wavefront before it moves on. It means that it turns slower through the more difficult parts and then faster through the clear glass. Even still, we realized that the aberrations were too large for us to correct. Dr. Bifano brought in some polyurethane spray and tried spraying three different microscope slides with different spray techniques. We measured the variation in the surface and experimented to see how well the controller could correct for them. We decided the best was the one that was sprayed with an even coat from a about a foot away. We were still worrying about how to make it go slower when Dr. Bifano had the idea of just moving the slide slowly horizontally instead of rotating the big wheel. We found a way to hook up the motor to the knob on a translation stage (which is a platform for mounting optics that lets you adjust its position). We realized the knob was going to slowly move away from the motor and then Chris had the idea of letting the motor ride on the stage with the slide. We all cracked up because it was such a perfect solution and we hooked it all up and it is exactly what we want. We can really move the slide slowly. We have it set to take about 20 seconds for a location on the slide to move from one edge of the camera to the other.
Meeting with undergrads
On Friday we had the great change to meet with four undergrad students who are spending their summer doing a "Research Experience for Undegrads." It was a chance for us to ask them about their high school experiences and how it prepared them or didn't for college. They admitted that all of the advice they had for us would not be popular with students but the students would thank us when they got to college. Their suggestions were NO calculators (even for logs!), more oral presentations, more pop quizzes, less hand holding. We talked a lot about the types of labs and projects they did in college and about how much they learned from being given an open ended problem and being forced to solve it without much guidance. They also suggested requiring students to solve the same homework problem multiple ways. They talked about different study habits that worked for them. One person said he practiced as many problems as he could - far beyond the set that was assigned. Another said he and his friends tried to figure out what the teacher would put on the exam and in doing so reviewed what were the important things they had learned. The time we spent with these very bright and candid students was priceless.
Thoughts about research
As we get to the end of our experience at BU I want to write down some thoughts that I want to remember when I get back to school. For one, I've seen there is a lot of value in getting to physically build something related to what it is you are learning. In a lot of my labs at Quabbin I only have one piece of lab equipment and we have to gather data from it together as a class which often results in me leading the experiment from the front of the class with student volunteers to help with different parts. Instead I would like to set up my class so that each small group of students has a chance to run the equipment on their own. During that time other students could be at other "stations" working on other problems or similar but different labs.
In our high school classes we are expected to know everything about what we are teaching and to be able to answer any questions the students have. In college, professors also teach classes and that part of their role is very similar. However, in college professors also participate in research with their students (typically graduate students). The research gives them a chance to make new developments in their field, but it also is a special way to provide students to work as apprentices and to learn by doing. While I don't anticipate making any journal worthy developments in research at high school, I am excited by the idea of doing solving some bigger open ended problems together with students after school. We were given a great set of problems to start me off from the Problem Based Learning workshop we had this summer. I would like to invite engineers and scientists from local companies and universities to come to Quabbin so that students can present their solutions to them and also hear about their jobs. I hope I can get some students interested in doing a club like this. I think it will help that the need to do a capstone project for graduation now and this would be a perfect capstone.
Next week will be a busy one with presentations and poster sessions. There is a lot to be done to get ready for those. I am hoping to enjoy the last week and soak up as much more as I can from here before I leave.