Natural-Uranium Heavy-Water Reactors
In the U.S. power reactors are fueled with enriched uranium and are cooled by ordinary water. The Canadian "Candu" system, working with unenriched uranium and heavy water, offers interesting alternatives...
Features
The Final Steps in Secretion
Precisely how does the living cell secrete substances? It seems that such substances are packaged in a membrane that releases its contents when it fuses with the outer membrane of the cell...
Quarks with Color and Flavor
The particles called quarks may be truly elementary. Their "colors" explain why they cannot be isolated; their "flavors" distinguish four basic kinds, including one that has the property called charm...
Image Reconstruction from Projections
A mathematical technique makes it possible to use a series of X-ray exposures made from different angles to reveal the internal organs of the body in cross section instead of superimposed on one another...
The Rise of a Maya Merchant Class
The centuries just before the Spanish conquest are usually viewed as a time of Maya decline and decadence. A review of the evidence suggests instead that new leaders were pursuing new objectives...
Active Animals of the Deep-Sea Floor
Baited automatic cameras dropped to the bottom of the ocean reveal a surprising population of large fishes and other scavengers that find and consume dead animals that fall from the waters far above...
Musical Illusions
Presenting certain sequences of tones simultaneously to both ears produces paradoxical auditory illusions. Surprisingly, right-handed subjects and left-handed subjects perceive the illusions differently...
The Debate over the Hydrogen Bomb
A recently declassified report sheds light on the original U.S. decision to develop the "Super." The unanimous opposition of the Oppenheimer committee, overruled then, appears now to have been basically correct...
Departments
50 and 100 Years Ago, October 1975
Science and the Citizen, October 1975
- Letters
Letters to the Editors, October 1975
- Recommended
Books, October 1975
- Mathematical Recreation
Mathematical Games, October 1975
- Amateur Scientist
The Amateur Scientist, October 1975
- Departments
The Authors, October 1975
Bibliography, October 1975
