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A secondary goal of this project is to introduce the emerging field of microfluidics. Microfluidics refers to the use of devices in which fluid flows are restricted to channels with micrometer dimensions. Such devices are interesting for at least 3 reasons:
In addition, this laboratory project is intended to provide an opportunity to learn about
Open-ended. You and your partner will be asked to design and carry out an experiment. A good experiment will lead to insight into some phenomenon that was not well understood before the experiment was performed. Your report will be graded based on (1) the coherence of the experimental design, (2) the reliability of the measurements, and (3) the appropriateness of the conclusions. If your results seem inconsistent with each other or inconclusive, that's bad. It is not important that your results support your preconceived notions or the theories we talk about in lectures and recitations. The first step to making a discovery is realizing when something interesting (i.e., unexpected) has occurred.
Partners. You will be working with a partner in all aspects of this project (proposal, experiment, and report). Properly managed, this can be an enormous benefit. Our experience with projects in 6.021J is that two students can make much more than twice as much progress on a research project than a single student can. We think that the reason for this is that a single student stops at the first barrier that he/she cannot overcome. By contrast, a pair of students stop at the first barrier that neither student can overcome. However, if poorly managed, working with a partner can be a handicap. If you find yourself in this situation, please consult with one of the instructors for help in getting back on track.
Staff. A research project is not like a test.
You are not expected to work in isolation.
You are encouraged to get outside help, especially from the teaching staff.
We want you to do a good project,
and we welcome the chance to help you think through your results and
plan the next step.
If others help you in significant and specific ways
(e.g., suggested a new approach), it is imperative that you
acknowledge this in an acknowledgements section of your report.
For more information about what to acknowledge and how to acknowledge it, see
http://web.mit.edu/academicintegrity/
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Proposal: Linearity of Mixing in Microchambers Partner Names (E-mail): Partner One (pone@email) and Partner Two (ptwo@email) Hypothesis: The process by which fluids mix as they flow through microchambers is linear. Background: The primary mechanism by which fluids mix when they flow through microchambers is diffusion. Since diffusion is a linear process (i.e., the relation between flux and concentration gradient is linear), we expect that the fluid mixing in microchambers will be linear. Procedure: A laminar flow chamber with two inputs will be used to assess fluid mixing in microchambers. The concentration of dye in the two chambers will be investigated in 3 conditions:
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This basic measurement will familiarize you with the experimental setup, in terms of both its capability and limitation. The main purpose of this pre-lab is to revise / improve your proposal, based on the reality / limitation of the experimental setup and the materials provided. Based on the basic experiment you made, you can improve your draft proposal, and make the experimental methods much more detailed. If time permits, you could even try to perform a preliminary experiment by trying to get one data point of your proposed experiment. Maybe you have suggested doing something that simply takes too much time. Maybe you did not know the exact concentration of solutes (or cells) you wanted to try. Fix any problems and make the proposal more realistic and focused, by talking to staff members present during the pre-lab sessions. The successful outcome of the pre-lab session should be a feasible proposal that will be approved by the staff members (TAs / project instructor / other staff members), which should be submitted to the course web site electronically by 5:00 PM on Friday, September 23. At the time of your submission of revised proposal, you should also submit a scheduling request for a 3 hour time block in the lab, to perform the proposed experiment.
Laboratory notes should be sufficiently detailed so that (1) the experiment could be repeated at some later time, (2) results from different experiments can be compared, and (3) so that your procedures can be reconstructed at a later time without relying on your memory. The first page for each experiment should give the date and time, as well as a brief description of the purpose of the experiment. All relevant procedures and observations should be entered in your lab notebook and the time should be indicated regularly.
Nothing should ever be erased. If an error is detected in some procedure or some reading, that should be noted in the book. The original observation should under no circumstances be obliterated so that it cannot be read. Perhaps you will subsequently find that the original observation was correct and that the correction was in error. The general rule is to write down everything that is done that may later become relevant. Scientists are rarely sorry that they wrote too much in the lab notebook -- only that they wrote too little.
You do not have to purchase a special laboratory notebook for this project. However, we do ask that you take laboratory notes during your experiment, as a step toward learning about effective practices in experimental work. You will be asked to attach your notes to your laboratory report, and we will assess these notes as part of the grading procedure.
Cover Page. On the cover page include the title of the laboratory session, the authors' names, your laboratory subsection, the dates of the laboratory session(s), and the name of your partner (if not a co-author).
Abstract. The abstract is a one paragraph summary of the report including the question investigated, the methods used, and the principal results and conclusions. Your intended audience (your classmates) should be able to understand the abstract without having to read any of the report. Since it summarizes your report, this section should be written last.
Introduction. The introduction is a brief section (fewer than 350 words) designed to motivate why your findings are interesting and important. The introduction should offer a rationale for your study. One way to motivate interest in your findings is to explain how your study fits within a broader context. For example, you could briefly summarize prior research in this field and argue that there are important unresolved issues (that just happen to be what you studied). Background information is helpful, but extensive library searches are not required. You may give citations to material from this website or elsewhere. The introduction should be directly relevant to your report; broad discussions of microfabrication or biology are not necessary or desirable.
Methods. Briefly describe the methods that you used to obtain and analyze your results. Avoid lengthy repetitions of materials that are easily referenced. Instead, simply provide a citation, such as "Osmotic properties of cells were studied using a microfluidics channel, as described on the lab website [1]." Methods should be organized topically, not chronologically. Avoid "First we did this, then we did that, then we did yet another thing." Break the methods section into subsections, such as "Measuring cell volumes" or "Compositions of solutions."
Results. Describe your technical findings (whether or not they fit with expectations). Generally, results can be communicated more efficiently and accurately with figures and graphs than with words alone. However, a collection of graphs without a written description of their relevance is not acceptable. The text of the results section should carry the reader through a presentation of facts that is intended to lead to a conclusion.
Discussion. Describe the major conclusions from the study. Explain the importance of your results -- especially how they bear on the issues you raised in the introduction section. It is often appropriate to point out limitations of your results (e.g., methodological errors, excessive scatter in results, or low statistical significance). The discussion section can also include relevant speculations and ideas for improving the experiment to test the hypotheses more rigorously.
Appendix. The appendix should include a copy of the notes taken in your lab notebook during the laboratory session. The appendix should also include your critiques from the technical and writing staffs, as well as the critique that you prepared for your peer.
Reports that are written haphazardly and without planning are usually unintelligible and receive poor grades. We strongly recommend that you start by developing a storyboard to structure the logic of the report. Revise your storyboard until the flow of your argument makes sense (ask yourself, "If this were someone else's report, would I believe the conclusion?"). At that point, you can usually write the report by fleshing out the outline.
First Draft / Writing Clinic
The deadline for the first draft is Oct 19th, 10:00am. Please turn in one hardcopy in recitation as well as an electronic copy via the subject website. Only pdf files are accepted electronically.
You will be assigned one first draft from a student peer group to critique. Your critique is due in the Writing Clinic to be held during normal recitation hours on Oct 26. At that time, you will get an opportunity to talk with the staff members (technical and writing) who critiqued your first draft. Final reports are due November 2. Turn in one hardcopy, complete with appendices (described above) plus one electronic copy via the web. One pdf files will be accepted electronically.
Throughout this project, keep in mind that you will NOT be judged on whether your predictions were accurate, or whether your measurements are consistent with the theoretical models presented in class. You will not even be judged on whether your final report answers the question posed in your proposal. What you WILL be judged on is your ability to formulate a question, make measurements to address that question, and present a coherent explanation of your results. A report that says "these measurements match theory", when they don't, will likely receive a very poor grade. A report that says "these measurements don't make sense" will score slightly higher. If the report suggests a reason why they don't make sense, the score will be higher still. The best reports will include additional measurements to test this new hypothesis, and show that it explains the observations.
The grade for the experimental project will be based on the proposal and on the project report using the following considerations:
First draft (10%). Your first draft will be graded primarily for completeness.
Critique of Peer (5%). The best critiques make high-level suggestions (e.g., suggesting major restructuring, new figures, ...), ask probing questions (e.g., could your result be explained by ...?), and make low-level comments (e.g., grammar errors, graphical errors).
Report structure (15%). All information in your report should be orgainzed in proper sections.
Clarity and Conciseness of Exposition (10%). A good report is easy to read. The content of each paragraph and each graph should be clear. Everything included in the report should be there for a reason. Points will be deducted for extraneous material. Reports should be less than 10 pages long, unless there are good reasons for additional pages.
Technical Clarity/Conciseness (10%). The techical content should be clear and concise. All technical points should appear for a reason.
Technical Content (20%). The best reports include a thorough investigation of at least one technical topic and contain no technical errors.
Insightfulness (30%). Insightfulness can be demonstrated by (1) proposing an experimental method that can resolve some scientific issue, (2) carrying out experiments and/or analyses that lead to clear conclusions, (3) preparing a report that demonstrates a clear understanding of the strengths and weaknesses of your results and analyses. Simply performing one of the standard experiments and showing unmotivated measurements will receive 0 points. Clever design of an experiment or imaginative analysis of the results will receive 30 points. Demonstrating a clear understanding of your experiment, your analyses, and what can be concluded is sufficient for 15 points.
For more detailed description, you can download the grading sheet for microfluidics projects
DUE DATES ARE FIRM, AND THERE IS A SEVERE LATENESS PENALTY. If you meet the both proposal deadline (9/16 and 9/23), you will get automatic full credit for professionality (5%). Also, if you miss the deadline for the first draft (10/14), you will lose 10% portion dedicated to the first draft. What is worse than that 10% credit is the fact that you will lose the opportunity to get feedback from your peers / staff members, which is a golden opportunity to improve your report.
The grade for a late (final) report will be multiplied by a lateness factor
L = 0.3 exp(-t/4) + 0.7 exp(-t/72)
where t is the number of hours late. The lateness factor is plotted below.
Notice that the maximum grade for a report that is more than ONE DAY LATE is less than 50%.