- Computers are needed for lab this week
- The laptops must be connected to their power bricks. There is too much signal noise if they are used without AC power connection. Power bricks are found in the non-Major's stockroom, shelf CC6
- Tips to improve signal:
- Clean the area of the skin well with alcohol and let it dry before applying electrodes
- Let contacts sit on the skin for a couple of minutes before connecting leads
- The wire from the EKG sensor labeled Lead I is connected to CH1 on the LabPro interface; Lead II is plugged into CH2
- The quality of the EKG is very much dependent upon the 'patient' used. Some will produce a very strong signal, others are basically walking corpses. If someone has a weak signal (typically in Lead I, containing no discernible peaks – Figure 1), they can use the sample Logger Pro file "Sample EKG Data.cmbl" found on T:\Phys104 (used for step #9 and later – Figure 2). Also found on the T: drive is "Sample EKG Data - Lead I Reversal.cmbl" for student use
- Here are my hand written solutions using the sample data. An average value of <r>=0.75 m was used
- The good sample data was collected by Clifford Reilly '16 and Fletch Starnes '16 on 10 March, 2015
Figure 1 – Bad
Data: Peaks not visible in Lead I |
Figure 2 – Good sample data on T: Drive |
- Students need to be reminded about how to add vectors graphically. Make sure they're drawing them tip-to-tail
- Throw away used electrodes when finished. The sheets of unused electrodes should be placed back in the foil envelope and used for later groups.
- All open packages of electrodes should be thrown away at the end of the week; new ones will be used the following year
- (Note: The Mathematica section has been removed as of Spring 2020) The Mathematica program, created by Brian Watson, can be a bit flaky. It will sometimes pause while running. Hit the play button to resume.
- During Spring 2019 semester, Mathematica would crash when trying to print. The solution is to use the Windows 10 "Snipping Tool" to capture a screenshot of the graph, and print the screenshot
- It's very important that students follow the directions of importing the data into Mathematica. They should not label the data columns, as this will confuse Mathematica
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