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JCE ChemEd Xchange provides a place for sharing information and opinions. Currently, articles, blogs and reading lists from ChemEd X contributors are listed below. We plan to include other items that the community wishes to share through their contributions to ChemEd X.

Hal Harris's picture

An Exact Value for Avogadro's Number

Thu, 03/01/2007 - 00:00 -- Hal Harris

The currently accepted formal definition of a mole is the number of carbon-12 atoms in exactly 12 grams of the pure substace. This is not a good operational definition, however, because it takes too long to find, purify, and count all those atoms. The best experimental value is based on x-ray diffraction experiments on silicon crystals and puts the number within 0.0000010 of 6.0221415 x 10^23.

Hal Harris's picture

Exploding Disk Cannons, Slimemobiles, and 32 Other Projects for Saturday Science

Thu, 02/01/2007 - 00:00 -- Hal Harris

Neil Downie runs a Saturday science program for kids in Guildford, UK, that appears to be the most fun that anybody could have. This book is the third in a series that describes projects that he has invented for kids to build and investigate (often with the help of an adult).

Hal Harris's picture

The God Delusion

Fri, 12/01/2006 - 00:00 -- Hal Harris

Unless you teach in a religiously-sponsored school, religion probably plays little role in your teaching of science. However, the "prior knowledge" of your students includes some decidedly non-scientific, religion-inspired viewpoints that ought to be taken into account.

Hal Harris's picture

The Rock from Mars: A Detective Story on Two Planets

Thu, 11/02/2006 - 01:00 -- Hal Harris

If you've been reading Hal's Picks for a long time, you might remember something about this rock, ALH84001, because the publication in Science of the paper that announced evidence in a meteorite that life had once existed on Mars was my Pick back in August of 1996. The article was controversial, as you might expect.

Hal Harris's picture

Fuels Gold

Fri, 09/01/2006 - 01:00 -- Hal Harris

The search for replacements for oil and natural gas is heating up, as the price of oil rises. No alternative is getting more attention than biofuels - which in the US means ethanol from corn or biodiesel from soybeans. The movement has terrific political momentum because it promises not only to increase the price of corn, but also to enrich those who have invested in distillation facilities.

Hal Harris's picture

American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer

Sat, 07/01/2006 - 01:00 -- Hal Harris

I am old enough to remember the 1954 hearings in the matter of J. Robert Oppenheimer, but I was too young to understand that there was more to this story about a supposed Communist in the nuclear weapons program than was being reported in the Los Angeles newspapers of the time.

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