Food Additives
Perhaps as many as 2,500 substances are currently being added to foods for flavoring, coloring, preservation and other purposes. How are the necessity and safety of these substances determined?...
Features
Nonvisual Light Reception
In the brains of some vertebrates are unidentified organs that respond to daylight. Experiments with blinded birds demonstrate that these organs control biological rhythms
Geosynclines, Mountains and Continent-Building
A geosyncline is a huge deposit of sedimentary rock that forms at the edge of a continent. When it is compressed, it buckles up into a mountain range. It also enables a continent to grow by accretion...
Electrostatics
The field around a charged body is used to manipulate particles of matter. Among the modern applications of electrostatics are fly-ash precipitators, paint sprayers and Xerox copying machines...
The Cave Bear
This large-headed species lived from the Pyrenees to the Caspian Sea during the Ice Age. One cave alone has yielded the remains of 30,000 such bears. What caused the species to become extinct?...
Do Infants Think?
They supposedly know the world only in terms of sensory impressions and motor activities. New experiments suggest that their cognitive, or hypothesis-forming, development begins at the age of nine months...
The Sources of Muscular Energy
The immediate source is adenosine triphosphate (ATP). The ultimate sources are the combustion of food and the breakdown of glycogen. The time relations of these processes offer some practical hints...
How did Kepler Discover his First Two Laws?
It is generally assumed that he did so by calculating the distances between a planet and the sun and then perceiving that the distances fitted into an ellipse. It is more likely that the ellipse came first...
Departments
50 and 100 Years Ago: March 1972
Science and the Citizen: March 1972
- Letters
Letters to the Editors, March 1972
- Recommended
Books
- Mathematical Recreation
Mathematical Games
- Amateur Scientist
The Amateur Scientist
- Departments
The Authors
Bibliography
