-
Falcon Heavy
I was supervising Jr IS, but as I circulated around the lab, I watched the clock. Everyone was working quietly. Just before launch, I snuck back to my office and closed the door. The SpaceX Falcon Heavy was surrounded by swirling clouds of condensation at Kennedy Space Center‘s historic Pad 39A. Amidst spectactors’ cheers and…
-
The Impossible Problem
In 1969, Hans Freudenthal posed a puzzle that Martin Gardner would later call “The Impossible Problem”. Below is a 2000 version due to Erich Friedman. I have secretly chosen two nonzero digits and have separately told their sum to Sam and their product to Pam, both of whom are honest and logical. Pam says, “I…
-
Electronic Kilogram
The kilogram is the only metric unit still defined by an artifact. The International Prototype Kilogram, IPK or “Le Grand K”, is a golf-ball-sized platinum-iridium cylinder in a vault outside Paris. This year I expect the General Conference on Weights and Measures to replace the IKP by an electronic realization that balances gravitational and electrical power.…
-
Taylor Bowl
On Wednesday, September 13, 1989, I met with newly elected Physics Club officers Tom Taczak ’91, Dennis Kuhl ’90, Doug Halverson ’91, and Karen McEwen ’90 in Westminister House. I wrote in my diary, “first phys club meeting w. officers goes well”. That year we invented Taylor Bowl, an annual bowling competition between the Physics and Math clubs, both…
-
Newton’s Can(n)on
One of my favorite illustrations is the cannon thought experiment from volume three of Isaac Newton‘s Principia Mathematica. Johannes Kepler argued that planets orbit elliptically with Sol at one focus. Galileo Galilei argued that terrestrial bodies fall parabolically in space and time. Living in the next generation and standing on their shoulders, Newton realized that…
-
Ein Stein
I’ve been fascinated by aperiodic tilings of the plane since Martin Gardner first wrote about them in Scientific American. In the 1960s, Robert Berger discovered a set of 20 426 prototiles or tile-types that can tile the plane but only with no translational periodicity — a wonderful mix of the expected and the surprising, a kind of…
-
Gossamer Flight
As a kid, I devoured the pages of Popular Science magazine and was fascinated by the quest for human-powered flight: Was a flying bicycle possible? In the mid 1970s, I read that aerospace engineer Paul MacCready had assembled a team to build a large, lightweight, human-powered aircraft that could be rapidly repaired and redesigned. In…
-
The Cupola
In the sky is a castle, built in free fall, brick-by-brick, where the sun rises and sets every ninety minutes. The castle derives its energy from sunlight and recycles its water. Sealed against a vacuum, its inhabitants float and glide through its passageways and gaze down at Earth through its expansive cupola. In an earlier…
-
The Falls
1930s businessman Edgar Kaufmann Sr. and his family lived in Pittsburgh Pennsylvania. Kaufmann owned a rural retreat outside the city and wanted a weekend home there. He assumed his 67-year-old architect would design the home with a good view of the Bear Run waterfall. Instead, the architect designed the home on the waterfall. Frank Lloyd…
-
The Burj
The tallest structure in the world since 2008, Burj Khalifa (or Khalifa Tower) is the fantasy skyscraper of my childhood. Designed by Skidmore, Owings & Merrill (SOM), with Adrian Smith and Bill Baker as chief architect and engineer, the Burj is aesthetically and structurally magnificent. No single photo can do the Burj justice, but the…
Thanks, Mark! I enjoy reading your posts as well.