Hal Harris

If you have students looking for an interesting science project, the May Scientific American has a nice one. A sun photometer can be used to determine the amount of haze in the atmosphere, and this article describes one that can be built in a couple of hours for less than $20 (although you also need to have a voltmeter).

The Bulletin for the History of Chemistry is the official publication of the American Chemical Society's Division for the History of Chemistry. The most recent issue is dedicated to the contributions of C. K. Ingold, one of the founders of physical organic chemistry. It records the proceedings of a symposium at the ACS meeting in Chicago in 1993.

The very first of "Hal's Picks", back in 1995, was the announcement of the first experimental observation of a Bose-Einstein condensate. This can be considered as a new phase of matter, in which atoms in a cold cluster lose their separate identities, because their deBroglie wavelengths exceed the dimension of the group in which they find themselves.

The origin of the molecular "handedness" that pervades earth's biology has been an evolutionary puzzle. Given that right and left-handed amino acids have equal energies, why do only the left-handed ones participate in biosynthesis? One hypothesis is that life started from templates that arose from extraterrestrial sources, such as meteors.

Science lost one of its most eloquent and persuasive spokesmen with the death last month of Carl Sagan. While he was best known as an astronomer and planetary scientist, The Demon-Haunted World should remind us that his interests were far broader than that.