Wednesday, July 30, 2008

The penguin from Ohio Wesleyn University, given to me by the physics department there. (There are penguins throughout Fundamentals of Physics, the textbook that I write.)

More images from the summer program (see below).

The Summer Honors Institute at Cleveland State University enjoyed the attendance of these local high school students, whose challenge was to create a power-point presentation for the last day.

Anirudh (Rudy) Jayanti, electrosurgery
Shoumik Pennathur and Nicholas Kar, projectile motion in air drag
Jeff Woos, Big Bang and more
Anupama Sundaram and Linda Nguyen, Newton’s laws
Nicholas Catalano and Katerina Glyptis, conservation of momentum
Liam Robinson and Sahil Gosain, Jesus lizard
Sandeep Sidhu, Galileo and his scientific works
Richard Kolk and Jeffrey Huynh, slinky physics
Yilun Cai and Jake Green, rattleback
Kyle Demko, conservation of energy
Kevin Russell and Diego Axon-Sanchez, density of objects (Archimedes)
Priya Datta and Faith Tandoc, the particle-wave duality of light

Sunday, July 06, 2008

Bottom: Amanda Beach, shown getting up on the bed of nails several years ago, has graduated with a degree in physics and will now probably move on to less hurtful things. Congratulations to her. Top: Amanda, Jearl, and Mary at Amanda's graduation party 6 July 2008.

Wednesday, July 02, 2008

In the latest set of stories at, I include several photos of the Millennium Bridge, which spans the Thames River in London, connecting the vicinity of Saint Paul's Cathedral (seen in the background here) with the Tate Modern museum. When the bridge was opened with great celebration to mark the new century, the first surge of people crossing it caused it to sway and gallop so much that some of the people had trouble keeping their footing. The engineers who designed the bridge were both stunned and embarrassed.

The physics is quite interesting because there was a feedback system at play. As the pedestrians walked, they pushed not only down but also sideways. At first all these pushes were randomly timed but once the density of pedestrians passed a critical point, the oscillations were large enough that many pedestrians could walk only by walking in step with the oscillations. That meant that many of them began to march in synchrony along the bridge, which caused the oscillations to build up even more, which caused even more pedestrians to march in synchrony, which ... well, you get the idea.

The bridge was closed while a solution to the oscillations was found. At the FCP web site I show some of the "mass dampers" that were now attached to the bridge to offset the pushing by the pedestrians as they walk along the bridge.

(Photo by Jearl Walker,