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Spring 2017, Phys 131, Reminders from 2-09 Training

Page history last edited by Kim Moore 3 years, 3 months ago

Reminders from 2/09 Phys 131 TA/LA Training, for week of 2/13 (Lab 1, Part 2):

 

Greetings, Physics 131 TAs and LAs!

Below are the reminders that I promised you from the most recent Thursday training session along with a little additional info about the videos (which we looked at in training).  Remember to bring your own TA laptop with you this week, so that you can play the videos with sound (Life of the Blood, Neutrophils (0-12sec), and Neutrophils (12-64sec)).  I have also attached a photo of the blackboard for this week.  When you have the lab reports from the students, please bring them to me in room 1322 (my office) so that I can scan them.  If you have them to me by 4pm on Thursday, I will have them scanned and back to you in training on Thursday evening  Good luck this week! ~KIM

 

1. Recitation: Forces for Objects and Systems

Link to recitation: http://www.physics.umd.edu/courses/Phys131/spring2014/Labs/Forces%20tutorial.pdf 

For more info on system schema: http://umdberg.pbworks.com/w/page/68452162/System%20Schema%20Introduction%20%282013%29

 

Students should NOT write on the "room copies" of the recitation paper.  Please collect the room copies between recitation and lab.  If supplies are running low, email Lead TA Kim ASAP.

 

The new vocabulary we covered was "Newton's 0th Law: Object Egotism."  We also talked about: i) writing Newton's 2nd Law in a particular format; and ii) how force vector labels should be formatted for this class.

 

(Break--Pass back graded Lab 1, Part 1; see 2 c below....)

 

2. Lab 1, Part 2:

Link to documents: http://umdberg.pbworks.com/w/page/68933700/NEXUS%20Physics%20Labs%2C%202013-2014

 

*Don't forget to read the TA document from beginning to end--most of what you need to know to run this lab is there.

 

Lots of stuff is going on in this lab.

a) IF you are using the SCL roles: The students should be working in their SCL roles (Journalist, Data Analyst, Critic and Checker--if you are using the roles with your students) and you should record which student is performing in which role (remember, they switch roles for every lab, so that they have done each role at least once in the course of the semester).  If they aren't sure what the roles are, refer them to the Scientific Community Lab (SCL)  document: http://umdberg.pbworks.com/w/page/58234096/Intro%20to%20the%20Scientific%20Community%20Lab

 

b) The students will turn in a FULL lab report TODAY (at the end of the lab).  If students ask what should be in the report, you can always refer them to the SCL document.  Also, your TA lab document includes the following: "Inform students that a lab report (discussing their qualitative and quantitative exploration of and resolution to the scenario) will be collected from each group at the end of the lab today (no error bars needed on graphs for this lab only). Feel free to say that again!  The students will push for an item-by-item list of what to write.  Don't give in!  They are asking you to do the thinking for them.....

 

c)  At some point you do need to pass back their graded data/graphs from Lab 1, Part 1 (amoeba).  I pass that back between recitation and lab (in the break).  I tell the students that "The Checker keeps the lab" when I pass stuff back, but there was no checker for Lab 1, Part 1, so just have them pick somebody to keep it.  Do point out to all students, though, that they should learn from the comments you made on their graded work to produce better data tables and graphs for the lab they are doing today!  The other nice thing about passing work back during the break is that students will have a chance to look through your comments without taking time away from the lab.  I tell students that if they have questions about their grade, they are welcome to ask me about the grading after the lab time is finished (or in my course center hours, etc.).  Also, don't forget to record the students' Lab 1, Part 1 scores in ELMS!!

 

d) As you introduce this lab and have students look at the sample videos, ask them which video looks the fastest.  Students can find these videos in the "My Documents" folder on the desktop machines.  You can also display these videos from the TA computer by turning on the overhead projector and pulling down the screen.  Can they tell which things are moving fastest using their eyes alone?  (These videos are often sped-up or slowed-down so that the action takes place at a rate comprehensible by our brains.  Hence the need for QUANTIFICATION to resolve the question of the need for antibiotics!)  Ask students what the possible scenario solutions would be (for each video being the fastest).  Ask students how they think the human body responds, immunologically, to bacterial invasion of a wound.  They are likely to indicate some sort of chase-and-eat mechanism (like a cops (neutrophils) and robbers (bacteria) simulation).  Show them the cartoon video (Once Upon a Time in the Life of....) and the first twelve seconds of the Neutrophil Extracellular Trap video--both on the TA computer in the 'My Documents' folder. BOTH of these videos show a chase-and-eat scenario.  (The classroom computers have no sound cards.  To play the files with sound, you will need to play the files from your own computer/laptop.  There should be speakers on the TA table to connect to your computer.  You can use the blue cable plugged into the back of the TA desktop CPU to connect the projector to your laptop.  Don't forget to turn up the volume on the speakers.  And DON'T show the second half of the Neutrophil Extracellular Trap video--save this for the end of the lab!)  {You can play these videos off of your own computer--files attached., or found here: Once upon a time... Life - The blood (1 of 3) (hq)_31-60s.mp4-.mp4 ; Neutrophil Extracellular Trap (hq)_0-12s.mp4-.mp4 (for use at the start of the lab); and, Neutrophil Extracellular Trap (hq)_12-64s.mp4-.mp4 (for use at the end of lab).}

 

e) You may want to hint to students that it is easiest to track objects moving either purely vertically or purely horizontally.  (They have only done 1-D kinematics, at this point.)  For the wound closure video, if they are tracking individual cells (instead of tracking the green 'wavefront'), the cells must be near the leading edge of the migration (cells near the edge move MUCH faster than cells not near the edge).  For the bacteria video, the majority of the E. Coli are NOT moving purely horizontally or purely vertically, but there are at least FOUR that do in the course of the video--they can find and track some of these.

 

f) This is students' first exposure to LARGE data files.  Help them learn to handle large data.  I added the following to the TA document:

A particular challenge for the students presented by this lab is the students' first interaction with LARGE data files (especially from the wound closure video).  You will need to help students learn to plan ahead in interacting with large data files:

  • ·         before starting a manipulation of data in Excel, they should create a back-up of the data (so that they can easily 'undo' any analysis mistakes and save themselves from having to analyze the video twice in ImageJ); and
  • ·         before starting a manipulation of data in Excel, they should also sketch out on the whiteboard what steps they will need to take to turn their data (slice and pixel information) into the physics quantities that they want—writing down the plan beforehand will help them be more efficient and will help them diagnose analysis problems before they happen.  (Left to their own devices, the students often analyze the data one lurching step at a time, without thinking about how the next step will/will not help them get to the quantity they want.  As a result, they will do many unnecessary/wrong calculations and will often, when they have finished, not have a clear understanding of what they have done.)

 

g) Students will turn in a lab and TAs should grade it.  (Remind them to put their names on the report!)  This lab is worth 15 points.  I promised you more information about what the lab report should include, what you should do as a grader, and what you should do to create a lab rubric.  I wrote it all up and put it on the wiki, here:

http://umdberg.pbworks.com/w/page/69242132/Hints%20to%20TAs%20for%20grading%20lab%20reports

I also included the rubric that I have used to grade this lab.  Let me know if you have any other questions or concerns.  (Keep in mind that the student participation, for Recitation and for Lab, is recorded SEPARATELY from the lab score.  Please track student attendance and participation in an organized way to make this part of your job easier on you!  If you have not yet entered the student participation scores for past weeks of recitation or of lab, please do so ASAP!)

* Grade in any color other than red (if you are able to do so).

* Enter the report score (out of 15 points) in the Lab 1, Part 2 column in the ELMS gradebook.  You need to get the graded reports back to the students before they turn in their next lab report (so by the start of Lab 2, Part 2).  Make sure that you have also entered the participation points for this and last week into ELMS.  Please keep up with the grading and participation scores!

* As you grade the labs, remember that you are shooting for a decent standard deviation.  I don't care what your average score is (they will be renormalized at the end of the semester to make the grading more fair for students with different TAs), but I need a decent point-spread in each section in order to renormalize properly.  Cumulative lab scores for the students are renormalized by me at the very end of the semester.

 

h) If you run out of paper for the printer, ask Bill Norwood (office directly opposite our room 3310) or Omar Torres (office directly next door to 3310) for more.  They are also the people you can get more staples from.  The stapler, in case you haven't found it yet, should be next to the printer or on the TA desk at the front of the room.  If you notice that the paper/staples are running low, please get more (rather than leaving the next TA running out of supplies)!

 

i) Getting the speeds for each video and answering the scenario question about prescribing antibiotics are NOT the end of this lab!  When we get a result that doesn't quite match our experience of the world, it is our DUTY to try to reconcile our experiences with this new information.  [Remember that part of what we are doing here is considering epistemology (What does it mean to know? How do we know that we know? and How do we build new knowledge?) and evaluating the fit between our model of the world and our measurements of the world.  If the model and the measurements don't fit, where does the source of the discrepancy lie?  Is the model flawed (if so, how do we fix it)?  Is the data analysis flawed (if so, what would need to be done differently)?  Is the data itself at fault (if so, how could the experiment be modified to produce better data)?]  In this instance, it seems we must modify our initial, simple model for the body's immunological response to bacterial infection of a wound.  In case you didn't catch all the cool options the human body uses to protect itself in response to uber-slow white blood cells, here is a recap:

  • NETS--ejects its own DNA as a sticky net (play the second part of the Neutrophil Extracellular Trap video--lots of cool bio words), and it turns out the NET is covered with antimicrobial chemicals;
  • large concentration--floods the region with LOTS of white blood cells--zone defense; and
  • establishing a perimeter--creates a bounded region surrounded by lots of white blood cells--road block ('encysting' the infection).

(Though there are certainly others!  For example, raising the ambient temperature (fever)....)

 

3. Other issues of note:

 

a) Handling questions about HW/Grading/WA: encourage students to get help solving problems in the course center (room 0208). 

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