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Spring 2016 Physics 132 Reminder from 4-22 Training

Page history last edited by Kim Moore 4 years, 2 months ago

Reminders from 4/22/2016 TA/LA Training (for week of 4/25; Lab 11)...


1) Recitation: Ultrasound--"Seeing" Inside the Body

Link: Seeing Inside The Body

Note: There are not quite enough copies for each student to have their own, but there should be enough for each most students to have their own.  When you reach the yellow tab in the stack, treat the remaining copies as "room copies."


(Break...  ALL students should enroll in a "Lab 11" group for your section in ELMS....)


2) Lab 11: Fluorescence

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 out their spectral graphs or take screen shots of their work, rather than saving the file (as they often accidentally over-write the main file!)


a) Fiber optic cables: Please review the 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).  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 reviewed with students.  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 review safety instructions for the light sources.  They should be aware that the ray box light source (incandescent bulb) used in this lab becomes 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 source for an extended period of time can cause damage.  Please make sure that all light sources are turned off when not in use and before students leave the lab room.  Additionally, the chlorophyll samples (suspended in isopropyl alcohol) should remain in the sealed bottles at all times.


c) Students will need to determine the best relative orientation of light source, sample, and detector for these measurements.  Make sure that they are justifying why the set-up they have chosen is the best.


d) Students need to collect data to observe fluorescence of the chlorophyll.  The spectra they include in their reports should indicate how they know that the observed spectrum indicates fluorescence (not just scattering of the source light).  We expect chlorophyll fluorescence to be observable for both the UV light source and the blue LED.  The incandescent bulb (white light source) should also cause fluorescence, but I am not sure if students will be able to collect that data cleanly.  In the past, some groups have also been able to detect fluorescence from the green LED.  The spectral data they collect can also help them determine the answers to some of the questions in Part II of the lab.   In gathering the data for their experiment for the blue and green LEDs, they will likely find it necessary to adjust the sample time for the data (from the default of 32ms to 100ms, adjust by clicking on the "Intensity" button above the graphical display) AND to adjust the vertical scale for the Intensity axis in the graph. 


e) When students ask for it, please provide them with the more complex and more accurate diagram of the energy levels for fluorescence (the Jablonski diagram).  These are on the 'TA' desk at the front of the room.  When lab is over, please re-collect these diagrams and place them, along with the fiber optic cables, on the TA desk.


f) Part of the point of this lab is for students to engage in a critical analysis of the multiple representations of fluorescence so that they can gain a better understanding of what fluorescence is and what measurements of fluorescence mean.  Remind students of this regularly.


g) As this is a one-week lab, lab reports should be submitted via ELMS in PDF format by the end of the 2-hour lab period.  Students also need to be enrolled in a Lab 11 group with their group-mates for their section.  Please double-check that everyone is enrolling correctly.  Students need only submit one report per group.


h) When the lab is over, please make sure that the room is straightened-up for the next section.  Re-collect all the fiber optic cables, along with the Jablonski diagrams.  Make sure that students put the other small equipment (Red Tide spectrometer, UV flashlight, and 3 LED lights) back in the cardboard boxes and these boxes back into the plastic bins in the back cabinet--please check these bins to ensure that the equipment is present and properly sorted.  The rulers/meter sticks, light ray boxes, and small stands can stay on the individual group tables.  Sort and stack the recitation and Lab 11 documents.


3) Logistics:


a) You should email me immediately if any students miss Lab 11.  I need to add them to the email about the make-up labs.  Also, please email me if you have any extra students, too, so that I can make sure a student attending a different lab section than their normal one is not accidentally considered completely absent from the lab.


b) We have training this coming Friday, 4/29, to train for the final recitation, the surveys, and the make-up lab (which will occur during the week of May 2nd).


That's everything for now.  Good luck!


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