http://mathforum.org/pd/contest2.html

eInstruction has announced the finalists of its fourth annual Classroom Makeover Video Contest.

The 15 finalists, representing the top video submissions from hundreds of entries from around the world, will be narrowed down to three grand-prize winners by a guest judging panel and through votes submitted by the general public on the contest site.

http://www.purdue.edu/impactearth

This interactive web tool calculates the potential damage caused by a comet or asteroid striking the Earth. With a schematic diagram dynamically updating along the way, enter information such as impact angle, density, and diameter of the object — or select suggestions from pull-down lists, such as "school bus - 40 ft" and "the moon - 3476 km." Then click the "Calculate Impact" button to watch from the projectile's point of view as it travels through space, into our atmosphere, and on to the Earth's surface. "Impact: Earth!" estimates consequences such as debris distribution, ground shaking, size of the resulting crater, and the likelihood of a resulting tsunami.

The creators of "Impact: Earth!" include astronomy professors and members of the science team from NASA's EPOXI mission, which flew to within 435 miles of the comet Hartley 2 last Thursday.

The largest known impact threat in Earth's near future is the asteroid Apophis, which scientists estimate has a four-in-a-million chance of striking the planet on April 13, 2036, seven years after it makes a record-setting — but harmless — approach no closer than 18,300 miles above Earth's surface.

http://www.chinesepuzzles.org/

New York City's first exhibition of antique Chinese puzzles has just opened at the Museum of Chinese in America (MOCA). Visit "Chinese Puzzles: Games for the Hands and Mind" in historic Chinatown now through May 2, 2011.

The accompanying website offers short illustrated histories, cultural connections, and solutions to classics such as the tangram, nine linked rings, ingenious rings, sliding block, and burr puzzles.

Curators Wei Zhang and Peter Rasmussen taught computer science and math before concentrating on collecting and researching Chinese puzzles. They became intrigued with these puzzles partly because of the mathematics underlying them. In addition to the well-known geometry behind tangrams, the nine linked rings puzzle, for example, features binary properties.

MOCA welcomes teachers and their classes to the museum to enjoy a display of beautiful antique puzzles — some made of porcelain, carved ivory, and mother-of-pearl — and to play with a variety of modern puzzles. MOCA also conducts hands-on sessions for school groups in the museum classroom; contact Karen Lew, MOCA's Associate Director of Education, at klew@mocanyc.org.