Winter Meeting: Tuesday Afternoon

I saw Kip Thorne's plenary session on black holes and gravitational waves - very interesting.  I didn't blog it because I needed all of my faculties to follow his tensor analogies. :)  The sensitivity of LIGO detectors (around 10^-16 cm) is about 10,000 times smaller than the width of a nucleus - that distance change over the distance of 4 km beam paths!

There's a post earlier about my talk, which was just after lunch.

Following that, I went into "Effective Practices in the Instructional Laboratory"

Slipping Spheres and Sliding Blocks: The "Role" of Kinetic Friction

• This session is mostly about the race of a sphere and block down a ramp
• It begins with a multivariate analysis of the parameters of the problems and how they affect the outcome of the race (low angles: ball, high angles: block)
• They go through the experimental setup for determining the motion data and friction coefficients
• There are some interesting (though small) changes to the friction coefficient - the sphere's decreased and the block's increased as the acceleration (in a half-Atwood system) increased
• They're the same material (wood), but the shapes might be an issue
• Nothing really here about using this in education, but it's a possible place for the AP class to investigate

Teaching Optics in the Introductory Mechanics Laboratory

• Labs tied to the course could become demos that don't engage the students and have them focus on too many components (apparatus, design, analysis, etc.)
• Instead, these folks keep the concepts pretty much the same during the term for the lab work, and don't progress with the material (kinematics and forces in first term, DC circuits in the second - which is in lieu of class instruction!)
• Intertwining of lab and class exposure causes analysis issue on how effective each component is
• They're using optics in the 1st term to free up time for other stuff in the 2nd term, and they never teach it in class then
• Optics labs: wrote and reviewed lab papers, did point and extended objects, refraction, beakers, lenses, not really any mirrors, modeling images
• Removed the mechanics labs during lab session, did some quick mechanics lab investigations in class instead (focusing on error analysis, etc.)
• Optics Concept Assessment pre-/post-test
• Students did as well on optics as students with more "rigorous" in-class experience
• FCI/FMCE gains were somewhat lower than in previous years, but he doesn't think that it was necessarily caused by the labs' removal
• Giving it 8 months later, students had basically forgotten their optics knowledge, but they have no previous tests to compare to
• Contact: masters@ipfw.edu

Assessing Student Learning of Error Propagation in the Undergraduate Lab

• Pre-/post-survey of error propagation using calculus method: addition adds direct uncertainty in quadrature, multiplication adds fractional uncertainties in quadrature
• HW from Taylor's An Introduction of Error Analysis
• TA didn't lecture during lab, so HW was never discussed as a whole
• Think-Pair-Share was used a bit
• There was a gain: 5/25 to 9/25 for one question, 5/25 to 15/25 for the other (significant gain)
• They classified the wrong responses: direct/fractional issues, typos, multiplying uncertainties, assuming dependence (adding uncertainty)
• The 2nd time, everyone at least tried it
• The pre-test was after a first semester though, so... yikes.  It's only a bit less scary after the 2nd term
• Contact: barker@nscl.msu.edu

I stayed for a couple of other talks here, but got tired of typing. :)

It has been a great Winter Meeting - thanks to all of the great speakers and the organizers!  After grabbing a bite, I'll head to the airport and back to the land of no palm trees.