Saturday Science Public Lectures

Fall 2017

by Dr. Michael Friedlander

The Department of Physics and University College will again sponsor a series of public lectures, to be held at 10 a.m. on Saturday mornings, October 28th – November 18th. Due to campus construction, all lectures will be held in the Laboratory Sciences Building in Lab Sciences 300. The Laboratory Sciences Building is directly across the street from the Millbrook Parking Garage, which is off the Forest Park Parkway along the northern end of the Danforth campus. These lectures, which are free and open to the public, will be presented by faculty members of the Department of Physics and are tailored for the general public. More information may be obtained at 935-6276 or on the Department’s website, physics.wustl.edu, by clicking on Events and then Saturday Morning Lectures.


Great Experiments of Modern Physics

The language scientists use to describe great experiments is interesting: words like beautiful and elegant are often used, as if an experiment was a work of art. Sometimes words like decisive or revolutionary are used, as if experiments were battles. In this lecture series, we will explore what makes a physics experiment a great experiment, exploring some contemporary experiments along with famous experiments in modern history.

Oct 25: Michael Ogilvie

Madame Wu, the fall of parity and the rise of the standard model
If you raise your right hand while looking in a mirror, the image in the mirror appears to have the left hand raised. This is an example of parity: the mirror image is equivalent to reality, but with left- and right-handed reversed. In 1956, an experiment by Chien-Shiung Wu at Columbia University showed that this equivalence does not hold in some nuclear decays: the universe is actually left-handed. This pivotal experiment began the journey to what we now know as the standard model of particle physics, the most successful fundamental theory of physics ever known.

Nov 4: Anders Carlsson

Getting a Handle on Mechanical Forces in Biological Cells
Mechanical forces are crucial in controlling many processes inside cells, and driving cell motion. These forces are generated by microscopic processes inside the cell, including growth of biopolymers, activity of motor proteins, and control of the chemistry of the cell. Fundamental understanding of these force-generating processes has been gained from ingenious physics experiments that determine the forces quantitatively in simple model systems. We will describe measurements of polymer growth forces, motor protein forces, and forces generated by the chemistry of the cell. Such measurements lay the foundation for a quantitative understanding of the cell that will have a lasting impact on health and our understanding of life.

Nov 11: Ramanath Cowsik

Does light gain energy when it falls under gravity?
When we drop a stone from a height it falls energetically onto the earth making noise and raising dust. The gain in energy is in proportion to the height from which it is dropped - greater the height from which it is dropped greater is the gain in its energy. What happens if we shine some light onto the earth from a high location; would the light gain energy? The answer to this question is ‘yes’ according to General Relativity developed by Einstein in 1915. In Physics, experiments stimulate theory, and theories suggest experiments that test them. The theory is accepted only when it is shown to be correct by the observations. In the year 1959, two scientists from Harvard, Pound and Rebka, conceived of a way to test this prediction of Einstein, which required a measurement with an accuracy of 0.000,000,000,000,004. By 1960 they completed the experiment to show that Einstein’s predictions were correct. This lecture is mainly devoted to a detailed recounting of their ingenious efforts that led to achieving such extraordinary sensitivity. During the intervening six decades the precision of the tests have increased 100 fold. We conclude with a brief description of the current theoretical perspectives and status of such experiments.

Nov 18: Carl M Bender

Why does thunder rumble?
The rumbling of thunder is not due to echoing off nearby buildings but rather occurs because of a strange property of waves in two-dimensional space. Is it possible to stop thunder from rumbling? Yes! All we need to do is to have an additional time dimension, and amazingly, beautiful experiments are being done right now that simulate a space of two time dimensions.

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