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novation Hyperlab provides access to a broad range of the tools of applied

physics and engineering in a single location and can disseminate resources

to schools around the Colorado region.

Location: Tate Lab 131

Sponsor: Committee on Physics in Undergraduate Education

Date: Monday, July 28

Time: 1:30–2:40 p.m.

Presider: Juan Burciaga

BD01:

1:30-2 p.m. Keeping it Fresh: An introductory Physics

Sequence for any Background

Invited – Dwight L. Whitaker, Pomona College, Claremont, CA 91711-6301;

One of the biggest challenges with serving a diverse population of students

with a range of high school preparations is to structure an introductory

course sequence that doesn’t repeat subjects for the well prepared or

alienate the less prepared. At Pomona College we have restructured our

first-year physics majors’ sequence so that all students start with the same

course. To keep the material fresh and challenging for all the students,

they start with a course that covers material usually reserved for a third

semester “modern physics” course (special relativity, quantum mechan-

ics, and statistical physics). By pitching these subjects at a level that all

students can grasp, we create a cohort of majors that all start in the same

place, which we believe improves our retention of majors. After their first

semester, students then take a semester of mechanics and E&M, which the

most advanced students can place out of and move onto our upper-level

offerings. We are now in our fifth year of this experiment and have seen an

increase in majors compared the previous model. The student feedback has

also been positive.

BD02:

2-2:30 p.m. Lower Division Honors Physics at UC Davis

Invited – Joseph Kiskis, University of California at Davis, Department of Phys-

ics, Davis, CA 95616-5270;

The Department of Physics at the University of California at Davis offers

a five quarter lower division honors physics course. This is in addition to

the two non-honors sequences of large courses—one for students majoring

the biological sciences and one for those in engineering and the physical

sciences. The honors course is primarily for physics majors and others in

the latter group, but all majors are welcome. I will describe the origin of the

course about a dozen years ago, its structure, texts, and teaching methods.

One of the main course goals is to introduce students to special relativity

and quantum mechanics during their first year.

BD03:

2:30-2:40 p.m. Honors Labs within Traditional Lectures

Contributed – Matt Evans, University of Wisconsin - Eau Claire, 105 Garfield

Ave., Eau Claire, WI 54701;

Erik Hendrickson U of WI - Eau Claire

Supplying a University Honors experience in physics is difficult due to the

limited numbers of students seeking this option and constraints on faculty

time. Our solution is to have all students participate in the same lecture,

but supply the honors students with a separate laboratory. This enables us

to craft more open-ended labs, dive deeper into the material, and challenge

these exceptional students without disenfranchising our regular students.

Examples of labs, assigned papers, and various grading methods will be

shared.

Location: STSS 230

Sponsor: AAPT

Date: Monday, July 28

Time: 1:30–3 p.m.

Presider: Hunter Close

BE01:

1:30-1:40 p.m. Upper-Division Student Difficulties with

the Dirac Delta Function

Contributed – Bethany R. Wilcox, University of Colorado, Boulder, CO 80302;

Steven J. Pollock, University of Colorado Boulder

The Dirac delta function is a standard mathematical tool used in multiple

topical areas throughout the undergraduate physics curriculum. While

delta functions are often introduced to simplify a problem mathematically,

students often struggle to manipulate and interpret them. To better under-

stand student difficulties with the delta function at the upper-division level,

we examined responses to traditional exam questions and conducted mul-

tiple think-aloud interviews. Our analysis is guided by an analytic frame-

work that looks at how students activate, construct, execute, and reflect on

the Dirac delta function in physics. Here, we focus on student difficulties

using the delta function to express charge distributions in the context of

junior-level electrostatics. Challenges include invoking the delta function

spontaneously, constructing two- and three-dimensional delta functions,

integrating delta functions in different coordinate systems, and recognizing

that the delta function has units. We also discuss possible implications of

these findings for instruction.

BE02:

1:40-1:50 p.m. Investigations of Spin First Instructional

Approach in Teaching Quantum Mechanics

Contributed – Homeyra R. Sadaghiani, Cal Poly Pomona, Pomona, CA

91768-2557;

We are investigating student learning of quantum mechanics in two dif-

ferent contexts. In one approach, postulates of quantum mechanics are

introduced in the context of the wavefunction of a particle in a box with

continuous bases of position probability densities. The second approach

uses the context of Stern-Gerlach experiments with discrete spin bases. We

have measured student learning of the core concepts in courses using these

approaches with common exam questions and a standardized conceptual

instrument. Preliminary data suggest a small but positive impact on stu-

dents’ scores on topics related to quantum mechanical measurement in the

classes taught using the discrete bases in the second approach. Preliminary

data also suggest that using the discrete bases approach may shift student

focus from computation to more sense making by providing concrete

experimental evidence and simplifying the mathematical calculation pro-

cesses. We will discuss the implications of this study for choices of initial

context, the order, and emphasis of content being taught.

BE03:

1:50-2 p.m. Student Reasoning about Superposition in

Quantum Mechanics

Contributed – Gina Passante, University of Washington, Department of Phys-

ics, Seattle, WA 98195-0001;

Paul J. Emigh, Peter S. Shaffer, University of Washington

Superposition is at the heart of quantum mechanics, and yet we have found

that many students struggle with this idea even at the end of instruction.

Although most students can successfully use the idea of superposition to

calculate probabilities of different measurement outcomes, we have found

that they often fail to recognize how a superposition state differs from a

mixture or from a system whose initial state is unknown. This distinc-

tion is one of fundamental importance in quantum mechanics and has

implications for more complex topics such as entanglement. We present

data from undergraduate and graduate-level quantum mechanics courses

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