September, 1997

October, 1997

November, 1997

December, 1997

January, 1998

When struck by a drumstick or beater, a drumhead vibrates in a complicated manner and radiates sound. In order to understand the vibrations, it is useful to describe them in terms of normal modes, which describe the motion of the drumhead(s), the shell, and the enclosed air. Vibrational modes and sound radiation from a variety of drums will be described in this talk.

Bells have been a part of nearly every culture in history. In this talk, we will compare church bells, carillon bells, temple bells, handbells and ancient Chinese two-tone bells. The talk will include videotapes of a wide variety of bells.

February, 1998

Place a hot, million degree plasma in a donut-shaped vacuum chamber and what happens? Two things of particular interest. First, magnetic field is generated spontaneously. Current flows in the plasma ``resistor'' with no applied voltage. This laboratory ``dynamo effect'' is similar to the natural dynamos found in the Earth, sun, and other stars. Second, the plasma, if unheated, cools down in one-thousandth of a second. These two macroscopic effects arise from tiny fluctuations, or waves, in the plasma which cause the magnetic field lines to wander chaotically in space. These effects are observed in the MST plasma physics experiment at the University of Wisconsin.

Our understanding of dynamo and energy transport has advanced to the point that we are beginning to control them. We can reduce the magnetic turbulence and the resultant plasma cooling, a result with impact on the quest for a fusion energy source.

March, 1998

April, 1998

Professor Herschbach will discuss recent progress in solving the 50-year old problem of identifying the origin of sodium nightglow. He has found new support for the proposition that sodium nightglow is generated by sodium atoms, ablated from meteors, undergoing reactions with ozone and oxygen. He and his research students are perhaps best known for their development of an experimental technique that employs colliding atomic and molecular beams so as to observe microscopically the temporal evolution of chemical reactions. At Harvard, Prof. Heschbach's introductory course is referred to as ``Chem Zen''.

Professor Herschbach will offer personal observations on teaching and learning, learning and teaching, and the architectural character of frontier science.

May, 1998

The Higgs boson is a hypothetical particle which may or may not exist. The Large Hadron Collider (LHC) in Geneva (to which I hope the US High Energy Physics program will make a major contribution) is not simply a machine to look for a particle that may not exist. Instead, the LHC is needed because we know that there is new physics involving the W and Z bosons that should begin to show up at the LHC. What makes it exciting is that we do not know what the new physics is. I will attempt to explain, in a very elementary way, accessible to graduate students and advanced undergraduates, how we can know where to look for this new physics, even though we don't know what it is. The answer has to do with symmetry and the scattering of Goldstone bosons. I will illustrate the crucial physics pictorially with computer animations.

June, 1998