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Spring 2016 Physics 132 Reminders from 4-08 Training

Page history last edited by Kim Moore 4 years, 1 month ago

Reminders from 4/08 Training (Lab 10, Part 1) for week of 4/11


Please make sure to get your Lab 7 and 8 scores into ELMS and to get the participation scores for labs and recitation up-to-date.  When your students' Lab 9 peer grading is ready, please update their Lab 9 score on ELMS.


Keep an eye out for students who have missed a lab (or two) and be sure to email the professor and Kim when a student's lab absences rise to two or more weeks.  Kim will be collecting info to schedule the make-up lab in a week or two (and will want to know, when she does, the student's: full name, email address, section number, and lab part(s) missed--start gathering this data now, if you think it will be hard to find!)....


1) Recitation: Diatomic Vibrations

Link: Diatomic vibrations


(Break...  Have students enroll in a Lab 10 group on ELMS...)


2) Lab 10, Week 1: Spectroscopy--Exploring Emission, Absorption, and Evolutionary Adaptation

Link: NEXUS Physics Labs, 2013-2014

File for use with spectrometer & LoggerPro: Spectrometer.cmbl --There is a clean copy of this file on the TA computer.  Ask students to print their spectral graphs (if they want to use the graph for their posters next week) or take screen shots of their work (needed for including the graph in their pdf lab report), rather than saving the file (as they often accidentally over-write the main file!).


a) Fiber optic cables: Please provide students with proper use instructions for the fiber optic cables.  These cables, costing over $200 each, should not be bent, coiled tightly, or crushed (pressed upon with sharp edges or great force).  There is a broken sample for them to look at--do not lose this sample!  Fiber optic cables should be stored between labs in the clear plastic boxes and kept up front on the TA table.  Do not pass out the cables until proper handling instructions have been given to students.  If students use the table stand and clamp in conjunction with the fiber optic, they should NOT tighten the clamp around the cable.  Check the fiber optic cables when you recollect them at the end of the lab--look for sudden kinks in the cable and make note of which group and which students in which lab were using the cable at the time.  We shouldn't have problems, but we want to know who to charge if there is breakage.


b) Safety Instructions: Besides proper handling for the fiber optics, students should be given safety instructions for the light sources.  They should be aware that all the light sources used in this lab become heated over time and should be handled gently.  Students should avoid looking directly at the light sources--no protective eye gear is necessary, but staring at a sodium or mercury lamp for an extended period of time can cause damage.  The sodium (Na) and mercury (Hg) lamps need time to warm up--so plug them in and turn them on at the start of Part II and do not turn them off until the end of the lab.  As with all labs, some of the equipment is heavy and should therefore be handled with caution, especially if they are carrying the heavy equipment between tables.  Water is also in use in this lab, so use the paper towels to clean up any spillage immediately.  To reduce danger from the fish tanks, Don and Kim have decided we should keep them on the rolling cart (in the back or center of the room).  This will keep the tanks out of the way during recitation and the first part of Lab 10 (when the tanks aren't yet needed).  The two TAs (and Don, if you call him in to help) can carry the fish tanks to the students' tables when each group decides they are ready for this equipment.  Please make sure the tank is placed on the lab table AWAY FROM the electronic equipment (computers, key boards, and electrical outlets).  When students are done using the tank, have a TA (or Don, if you let him know) replace the tanks on the rolling cart.


c) Equipment Locations: The hydrogen, sodium, and mercury spectral lamps should be stored between labs on the empty table at the back-left of the lab room.  The Red Tide spectrometer and the table stand (and the light ray box, perhaps) should stay on the tables throughout lab and recitation.  The fiber optic cables should be stored in the clear plastic boxes and kept on the front TA table between labs.  All other equipment (including the UV flashlight, LED lights, hand-held spectrometers, diffraction grating, plate of glass, and various filters) should be stored in the cardboard boxes, placed two-per-plastic-tub, and placed in the cabinet at the back-left of the room.  Please check that all lights/lamps are turned off at the end of lab and that all equipment is stored properly before the lab is over and students leave.


d) Introduction to lab: As with other labs this semester, this lab has two main purposes beyond the normal physics content--1) helping students understand a common piece of instrumentation often used in biology and chemistry classes (the spectrometer), and 2) helping students understand that experimentation is a legitimate source of new information and the most common way that scientists acquire new knowledge (that's why we have some of our labs AHEAD of the lecture material)!  Things observed in and understood fully via experimentation can exist for DECADES before being fully and accurately encompassed in theory!


e) Progress: This week, we expect that students will complete Part I (exploring the spectrum of Hydrogen) and Part II (investigating combinations of sources and filters).  Please push to make sure that students take a spectrum for the UV light, for sunlight, for the ray box's incandescent bulb, and for water as a filter and glass as a filter.  Some groups may move on to start Part III--but the above-listed specific things will be needed to form data-based, plausible hypotheses for Part III, so don't let students finish Part II until they have completed these investigations.  The two tables in the back of the room should be able to capture the sunlight--I think the USB cables for the Red Tide Spectrometers are long enough--other tables will not be able to do so as they are too far away from the windows.  In order to get everyone sunlight data (and to make sure they get both Na and Hg lamps, if they'd like) some group table/station rotation is necessary.  For night-time labs, I have attached a set of 'training materials' that I use with TAs--this is old data from previous years; you should find pages 9 and 18 of this pdf file contain the data you need to argue that an incandescent source is a good approximation for the sun.


f) Clean-up: Please check that all lights/lamps are turned off at the end of lab and that all equipment is stored properly before the lab is over and students leave.  Have students wipe up any spilled water and straighten up their paperwork.  All lab/recitation documents should be placed in the proper pile at the back of the room on the printer table.


g) Data handling: Every member of the group should have a copy of ALL of the group's data before leaving the lab.  If the group has chosen to print the spectral graphs, then whichever student takes the graphs must PROMISE to be present at (and to bring the graphs to) the following week's lab session.  Student absence is no excuse for having an incomplete lab report in the second week--lost work will need to be DONE AGAIN in the second week.  (Scare them good and you should have no trouble!)


h) Looking ahead to next week....  (To keep in mind, in case any groups start working on Part III this week....)

Part III: Plausibility hypotheses supported by data....  Your task as TA is to prompt students to engage in a good discussion of evolution of the human eye, enforcing the need for their hypotheses to be supported by data they have taken in the lab, without getting in the way.  You are NOT the evolutionary biology expert.  That is our students' job!  We want to study what they do and say in as authentic a way as possible, so please try to minimize what you say and, if you have to say anything, please try to avoid the non-normative ideas.  Do not try to influence whether students are using normative/non-normative ideas, just try to avoid being the person who inserts non-normative ideas into the students' discussions.  Remember that few undergrads have a stable, coherent, "expert-like" model of the criterion for (core ideas of) natural selection--and they are much better at reasoning on trait gain than on trait loss/lack.  Here is a summary of what we reviewed in lab training:


Normative core ideas for natural selection:

Mutation, Genetic recombination, Genetic drift, Sex, Heredity, Differential survival/reproduction, and Limited resources.

Non-normative ideas:

Teleology (needs cause evolution), Disuse-inheritance (use impacts heredity), Intentionality (mental states cause evolution), Essentialism, Adaptation/Acclimatization (simultaneous change to the environment), and 'Pressure' as cause.


Good luck!



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