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Physics & Astronomy Seminar
Spring 2001

Seminars are held on Tuesdays, 3:45-4:45pm in SB 101, unless otherwise noted.
Meet at 3:30 in SB 157 for refreshments.
See Calvin's Visitor Resources for maps and directions to the Science Building.
If you would like to receive regular email announcements for each week's seminar, or have other questions or comments, contact seminar chair Deborah Haarsma.

Previous semesters: Fall 1999, Spring 2000, Fall 2000

Date	Title (click on title to see abstract)	Speaker
January 30	The Physics of Ink-Jet Printing	Dr. Hubert Vander Plas `72, Hewlett-Packard
February 6, in SB110	Quantum Computers and Schroedinger's Cat	Prof. Christopher Monroe, University of Michigan
FRIDAY, February 9, in SB110	From Space Surveillance to Microelectronics: An Overview of Research at Lincoln Laboratory	Dr. Matthew Vanderhill `69, MIT Lincoln Laboratory
February 13	Viewing of The Fire That Burns Within
February 20	An Inside Look at Teaching High School Science: Dazzling Demos and Beyond	Dan Zuidema `99, Grand Rapids Christian High School
February 27	Quiz the Professors	Calvin faculty
March 6	Refreshments only
March 13	Save That Dross! How "Refining Your Silver" Might Best Be Left to Matters of Spiritual Purity	Prof. Harold Schnyders `91, Lake Forest College
March 20	Spring Break
March 27	Refreshments only
April 3	Development of a simple electrodynamic loudspeaker for use as a student laboratory project	Prof. John Krupczak, Hope College
April 10	Refreshments only
April 17, in SB110	Exploring the Universe, One Picture at a Time: An Update on Calvin's New CCD Camera	Calvin Observatory Assistants (Andrew VandenHeuvel, Joshua Gabrielse, Catherine Boersma, Peter Schrock, Phil Ammar, and Adam Bentham)
April 24	Advising Recess
May 1	Whiter than White, Blacker than Black, Greener than Green: The Perception of Color	videotaped lecture by Dr. Robert Greenler
May 8	Red Giants to White Dwarfs: Studying the Transitional Objects	Prof. Bruce Hrivnak, Valparaiso University

February 6: Quantum Computers and Schroedinger's Cat
A "quantum computer" can store and process quantum superpositions of numbers. This parallelism leads to an exponential speedup over conventional computers for certain algorithms. However, the prospects for constructing a quantum computer are highly speculative, owing to the extremely fragile nature of quantum superpositions: a quantum memory must be sufficiently isolated from the environment to prevent a collapse of the superposition. A quantum computer is nothing more than a smaller (and more humane) version of Schroedinger's Cat, and if one is ever built, it will strongly impact both computer science and fundamental quantum mechanics. A leading physical candidate for a quantum computer is a collection of trapped atomic ions. Experiments with individual trapped atoms are reported in this context, including the demonstration of simple quantum logic gates and the controlled generation of "entangled" quantum states. The outlook for future quantum computing using trapped atoms or alternative technologies will be discussed.

Feb 13: Viewing of "The Fire That Burns Within"
Video interviews with 10 physicists employed in a wide range of careers.

Feb 27: Quiz the Professors
A panel of Calvin physics & astronomy faculty answers your questions about careers, grad school, planning your major (or double major or minor), summer research opportunities, physics as a Christian vocation, etc. Bring your questions!

March 13: Save That Dross! How "Refining Your Silver" Might Best Be Left to Matters of Spiritual Purity
Magnetoresistance, the change in electrical resistance of a material placed in a magnetic field, is of tremendous importance to the multi-billion dollar per year disk drive industry. Many scientists (including Calvin's Prof. Steenwyk) are engaged in the optimization of a material or device to have the largest resistance change in the smallest applied magnetic field. Recently, non-magnetic Silver Telluride (Ag2+dTe) was seen to display a massive, linear with magnetic field resistance change [1], even at room temperature. However, when a mere 0.1% of the dross is consumed ( d = .0012), the effect is severely diminished. Come, refine your thinking on what might someday supplant the spin-valve as a piece of your 1 terabyte hard drive.
[1] H.S. Schnyders, M.-L. Saboungi, T.F. Rosenbaum, Appl. Phys. Lett. 76, no. 13, 1710 (2000).

April 3: Development of a simple electrodynamic loudspeaker for use as a student laboratory project
The development of an inexpensive electrodynamic speaker as a laboratory project which students can build and take home will be described. The speaker produces a loud and clear sound when connected to a home audio system. The speaker serves as an example of the application of electromagnetism in a familiar technology device. The simple speaker uses a plastic drinking cup as a base, a tight-fitting lid as the cone, and a drinking straw as a support for the voice coil. Non- obvious aspects of development will be highlighted such as the use of finite element modeling to design the magnetic field in the voice coil. The talk will include a hands-on activity.

April 17: Exploring the Universe, One Picture at a Time: An Update on Calvin's New CCD Camera
We have had the privilege to be the first to enjoy Calvin's new CCD imaging camera and accessories. Students are now able to take the universe, once visible only temporarily, and place it on their bulletin boards for 'day'ly viewing. Come and see the marvelous things that are happening on the science building's fourth floor.
We will discuss what a CCD camera really is, including how it works and why it works. We will see the images already taken here at Calvin, and learn how we process them to get valuable scientific information (not to mention, pretty pictures). And we will explore what lies ahead for the observatory and the CCD technology here at Calvin. Come learn about the equipment that is changing the way astronomy is done at Calvin.

May 1: Whiter than White, Blacker than Black, Greener than Green: The Perception of Color
In this videotaped lecture, Dr. Robert Greenler explains through clever demonstrations the nature of light, the way color works in opaque and transparent objects, and the characteristics of the human eye that influence our perception of color.

May 8: Red Giants to White Dwarfs: Studying the Transitional Objects
While stars appear to be unchanging, they do change and evolve over long periods of time. Stars like our Sun eventually expand to become red giants, lose their outer gaseous atmospheres revealing their cores, and then gradually cool to become white dwarfs, the final "death" of most stars. I will report on my study of stars in the transitional phase between red giants and white dwarfs, which I have carried out using telescopes on mountain tops and from space. This has revealed new information about how stars lose mass and the chemistry of the gas.