Desalting Water by Freezing
The alleviation of shortages of fresh water is often viewed in terms of distillation or the electrical removal of ions. Processes based on freezing crystals of fresh water out of salt may be more economical
Volume 207, Issue 6
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Features
Atmospheric Tides
Tiny regular pulsations of the atmosphere have long been attributed to the pull of the sun and the moon. Rocket observations now suggest that the cause is the absorption of ultraviolet radiation by ozone
The Evolution of the Hand
In 1960 tools were found together with the hand bones of a prehuman primate that lived more than a million years ago. This indicates that the hand of modern man has much earlier origins than had been thought
Biological Luminescence
A remarkable variety of organisms from bacteria to fishes shine by their own light. The light is produced by diverse chemical systems, the best understood of which is the system isolated from fireflies
The Conduction of Heat in Solids
It is a familiar observation that some materials are better conductors of heat than others. The process is governed by the properties of a unit of sound energy known as the phonon
The Use and Misuse of Game Theory
Can this fashionable technique really be used to solve the problems of human conflict? The author believes that it cannot, but that it can teach us what to do in order to solve such problems rationally
Surface Tension in the Lungs
Recent investigations have shown that the air spaces of the lung are coated with a complex substance that lowers surface tension. It now appears that this substance keeps the lungs from collapsing
Ultraviolet Radiation and Nucleic Acid
The damaging effects of ultraviolet on living things have long been known. Now they are being explained in terms of specific changes in molecules of the genetic material