Modern Physics

A workshop presented 13 November 2004

In honor of the 2005 International Year of Physics and the 100'th anniversary of Einstein's marvelous year of 1905. In 1905 Einstein published three papers

The first explained the photoelectric effect by postulating the quantization of light.

The second proposed the special theory of relativity

and the third used a mathematical description of Brownian motion to prove the existence of atoms.


General Relativity and the Universe

The overall lecture with demonstrations is available here "The Expansion of the Universe"

Curved space, There is more distance between two objects when a massive object is brought nearby..

Balloon Universe Blow up a balloon and model the expansion of the universe.

Circle Universe, simplify the Universe to one curved dimension.

Curved pi, measure the value of "pi" on the surface of a balloon.

Expansion of light, when light travels through an expanding universe its wavelength is stretched.

Expanding Universe, Use two transparencies to show how everyplace is the center as the universe expands

MR diagram, graph the mass versus radius of everything in the universe.

Relativistic appearance of stars, a series of images

Universe City size, Map the entire universe onto 14 city blocks.

Universe City time, Take a walk down a street where light travels 1 block per decade.

GPS and general relativity, clocks run slower in a gravity field. Atomic clocks in orbit used by the global positioning system gain 38,000 nanoseconds a day, this would lead to a daily error of 7 miles in position unless they are corrected for general relativity.

Gravitational Lens, The stem of a wiinegalss can be used as a lens to make images like those made by massive objects.

Special Relativity in your television, electrons in your television travel from the rear of the cathode ray tube to the front at about 1/3 the speed of light.

Gravitational Lens, use the optics of the stem of a wineglass to simulate gravitational lensing.

Quantum Mechanics

Energy Level Model, use a stool to illustrate energy levels of an atom.

Energy versus color , red green and blue LEDs turn on at different voltages

Bohr atom model, Use a gravity well to model how stable electron orbits form around a proton.


A readable non-mathematical book on relativity is "Was Einstein Right?" by Clifford Will

An excellent mathematical introduction to relativity using algebra, and vectors is "Spacetime Physics" by Edwin Taylor.

An excellent discussion of the Twin Paradox is available on line at the Physics FAQ site.


Scientific Explorations with Paul Doherty

© 2004

8 November 2004