Thursday, March 13, 2014

Make a graph

Help me help you. There seems to be some confusion that I'd really like to be able to clear up and I'd welcome some feedback. In the at-home lab activity we recently did for class (, the first data analysis section says:
My intention here was that the students would take the time-dependent temperature data they collected and prepare a plot that looks something like this:
{NOTE: This plot contains more data that I expect in the student experiment.}
A significant number of students did not realize that they needed to include a graph as part of their data analysis and assignment. I don't understand why this was not clear. I am not being snarky or condescending or angry or mean when I say that, I honestly don't understand why that instruction in the "Data Analysis" isn't clear, so I would sincerely appreciate any help on how to write that instruction more clearly. I have a couple ideas of why this was not an effective instruction:

  1. The word "plot" doesn't mean the same thing to everyone. Is there a better word that would make this more clear? Graph? "X-Y scatter plot"? I do not require students to use a spreadsheet to generate their plots because I don't want to introduce additional barriers and hand-drawn plots/graphs are sufficient for the data presentation and analysis in this class… Would it be better to require computer generated plots/graphs just to reinforce that a graph is required for the data presentation and analysis?
  2. Is this more a symptom of the broader problem of "science is hard" rather than poorly written instructions? If a student firmly believes that "science is hard" or "I'm not good at math", then the student is likely to accept a lower standard for himself or herself and perform below his or her abilities. 
  3. Do the students just not care? I refuse to believe that this is the most common problem; the vast majority of the students in this class are dedicated hard workers and really want to learn something. At the same time, the students taking this class are not (on average) the typical "sciencey" student, they are taking this course because they see it as one of the easier options for fulfilling the science requirement of their degree. That means that there are at least a few (and they're usually not that hard to identify) who are just in the class to do the bare minimum to pass and have no real interest in learning any more than they need to squeak by with a "C".

There is no magic single answer to this issue, BUT if there are some simple fixes (change the wording, etc) that will help some students succeed in this class, I'm happy to consider them. Anonymous comments are permitted here, so feel free to be as open as you would like. I'm always open to learning new and better ways to do things, so open feedback is helpful.

Sunday, March 9, 2014

Lab Assignment Tips

After looking over your Lab 1 assignments, there are a couple general points that I think would help everyone make some improvements on future assignments:

1. Individual vs Group Assignments
For your labs (and everything else in BCBT 100), you must turn in individual assignments to receive a grade. Even if you're working with a partner (or 2) on a lab experiment, each partner is required to turn in an individual assignment for grading. This doesn't just mean 2 copies of the same assignment with a different name at the top (that would be plagiarism and could result in your expulsion from the University), but individual assignments from each partner. I expect and encourage you to discuss your experimental observations and conclusions with others in the class, and if you are working with a partner I expect that the raw data you use will be the same, but your responses to questions should be yours and in your voice

2. Complete Answers
Especially in labs, always assume that there is a "Why?" or an "Explain" part of every question. Give me an answer that shows me a little bit of your thought process. "How confident are you in the accuracy of your result?" shouldn't just be answered with "Very confident" or "Yes." {I'm not sure how "Yes" even could be an answer to that question...} If you are "very confident" in your result, there must be some reason for your confidence. And no, the answer is not "I am very confident in my result because I am just that good." An answer that would be quite convincing and give me a good indication of your thought process would be something like "The error in our repeated measurements {+/- 0.014} is quite small compared to the average of the repeated measurements {17.372}, so we are very confident in the precision of our answer." I can say with nearly 100% certainty that I will almost never ask a question that I expect to be answered with a single word. 

3. Show Your Work
Whenever you have to do any math, show at least 1 sample calculation for each step of the math you have to do. It's not always obvious there some of your numbers come from, so a little bit of help would be nice. {This is closely related to the "Complete Answers" tip above...}

4. Graphs Should Fill the Available Space
This is especially true when you're trying to fit a line to a bunch of data points by eye. If you have a half page of space for your graph, don't squeeze all the data into a little postage stamp in the corner. By spreading out the data, you will minimize the error in your line fit. Scientists devote a stunning amount of time to analyzing and trying to minimize error in their experiments; be a good scientist!

I'll post more tips as they come up. When in doubt, always ask.

Wednesday, March 5, 2014

Study Guide Answers

A few people have asked if I'm going to post "answers" to the study guide for Exam 2.

Short answer = no.

Less short answer = The "answers" are already posted. For Exam 1 I posted specific sample multiple choice questions, so there was an answer key. For Exam 2 (and likely Exams 3 & 4...), I posted a study guide that contains open-ended questions. The answers to these questions are contained in the slides I used in class and/or the assigned readings from the textbook. By posting questions this way, I hope to encourage you to think about many of these concepts a little more broadly rather than focus on picking the exact right answer from a list of possible choices.

For those of you who may be a little anxious that the exam will be a whole different format than Exam 1, fear not; your actual exam will still be multiple choice. By preparing for the exam with open-ended questions, you will be better prepared to answer a variety of multiple choice questions on each topic rather than just answer the exact questions you have studied. Some of the study guide questions will probably show up on the exam as multiple choice questions, but by preparing for those questions without the restriction of a specific set of multiple choice options, you will be better prepared to succeed.

If you really want to see something that looks like answers to some of the questions on the study guide, many of these can be found in one of these links:

Good luck.