USIYPT 2019: Problems

Rye Country Day School, January 26-27, 2018, Rye, New York

1.  Extraterrestrial Rainbows:

When it is both sunny and rainy, we see rainbows.  What if, rather than water, it rained some other clear liquid, as it does on Saturn’s moon Titan?  If, someday, future astronomers took a picture of a non-water rainbow, could they determine the chemical composition of the raindrops from the image?

Investigate, both experimentally and theoretically, the physics of rainbows caused by a variety of clear liquids.

2.  Faraday’s Homopolar Generator:


Michael Faraday set up a round copper plate in a magnetic field and used it to generate current, which he measured using a galvanometer.

Reproduce Faraday’s experiment.  Investigate how it works both experimentally and theoretically.

3.  Juggling Hammers:


Hold a typical carpenter’s hammer with the claw up.   Throw it in the air, catching it by the handle after a single rotation.  The claw will still be up.  Paradoxically, if you turn it 90 degrees and throw the hammer again, the claw will now be on the opposite side.

Investigate this both experimentally and theoretically.

4. Pneumatic Tube Mail Systems:


Up until the mid 20th century, pneumatic mail systems were installed to quickly transport small items over short distances but they sometimes exploded when scaled up over longer distances.

Design, and build, a working pneumatic tube mail system.  Investigate the feasibility of using such a system for high-speed travel.

1. Image credit:  Colin Leonhardt, in Science News, October 20, 2014

2. Michael Faraday, Experimental Researches in Electricity, 3 vols. (London: Taylor, 1839, 1844; Taylor and Francis, 1855) I: 26, para. 88.

4. Caption: “Helen Soros works the new pneumatic tube system to take cash at Marshall Fields store in Chicago, November 26, 1947.”