Results

The tournament was hosted virtually by USAYPT due to the ongoing pandemic. The USIYPT 2021 champion is Phillips Exeter Academy, with second place going to Woodberry Forest School. The Swartz Trophy goes to The Nueva School. The Bibilashvili award went to all eleven participating schools..

2021 Problems

CHATTER RING The Chatter ring, also Gyro ring or Jitter ring, is a toy with small spinning rings, called beads, around a big hoop, called the ring. The goal is to keep all of the beads spinning for as long, and as fast, as possible. [1] Investigate how one works, both experimentally and theoretically.

[1] The Chatter Ring has been marketed also under the names Gyro Ring, Jitter Ring, and Flitter Ring, with a retail price of under US$20.

LAVA LAMP Edward Craven Walker and David George Smith invented the Lava Lamp in 1963[2], and it soon became a fad, remaining popular throughout the 1970s. Investigate, both theoretically and experimentally, the physics of lava lamps.

[2] The figure is from US patent US3387396A, which was filed along with UK patent GB1034255A, on March 18, 1964.

MODELING IMPACT CRATERS What happens when a large rock hits a planet or moon? Does it matter if it hits the water or land? How much kinetic energy does it take to produce a crater of a particular diameter? Where does this energy go during the impact? What forms the central peaks found in some lunar craters such as Tycho [3] shown. Conduct experiments designed to reproduce the shape of various terrestrial and lunar craters. Use your experimental results, and appropriate scaling relations, to estimate the energy needed to produce observed impact craters. How do your results compare with estimates from the scientific literature?

[3] The top figure is a mosaic of images taken with the Lunar Reconnaissance Orbiter, by scientists at NASA/Goddard and Arizona State University, while the bottom is a view of the central peak by the same team.

JOSEPH HENRY’S ROCKING MOTOR In 1831 Joseph Henry invented the first electromagnetic motor, or as he put it: “I have lately succeeded in producing motion in a little machine by a power, which, I believe, has never before been applied in mechanics—by magnetic attraction and repulsion.”[4] Read Henry’s article and reproduce his experiment. Clearly explain how it works using Henry’s reasoning, and then using modern electromagnetic field theory. Next, design and build, a solar powered electromagnetic rocking motor optimized for pumping water in an arid rural area.

[4]Henry, Joseph, On a Reciprocating motion produced by Magnetic Attraction and Repulsion, American Journal of Science and Arts, (1831) Vol. XX, No. 2, Art. XVII, pp. 240-343.