Scientific American Magazine

The fourth in a series of reports on racial attitudes shows that U.S. whites have increased their support of integration at a steady pace, with a striking period of more rapid change between 1970 and 1972

Long before the Sumerians invented writing, accounts in western Asia were kept with clay tokens of various distinctive shapes. It appears that the tokens gave rise to the Sumerian ideographs

Among the light elements nuclei with unequal numbers of protons and neutrons are highly unstable. Some survive just long enough to be detected and exhibit unusual regimes of radioactive decay

Intense radiation at microwave frequencies is emitted by certain nebular regions and stellar atmospheres. It is generated by maser action, which does for microwaves what laser action does for light

Computer simulations of development make it possible to perform experiments that cannot be done in the biological laboratory. They help to reveal some of the basic forces that sculpture the embryo

Complex systems such as telephone exchanges and computers consist of large numbers of simple components. Complexity theory seeks to establish the number of components needed to perform a given task

The forces that erode stone in nature also erode it when it is used for buildings, and they are intensified by contaminants in the air of cities. The erosion can be retarded by novel chemical treatments

It is described for Ades aegypti: the female of which feeds on blood. The feeding apparatus is not some kind of hypodermic needle but an exquisitely made piece of biological machinery