The human population is now about 3.6 billion. An extrapolation of present world demographic trends that lies between two extreme projections shows it leveling off at some 8.4 billion by the year 2100...
By Tomas Frejka
The Fine Structure of the Earth's Interior
The waves sent out by earthquakes and nuclear explosions have been studied in detail with new seismometer arrays. They show, among other things, that the core of the earth has a solid kernel...
By Bruce A. Bolt
The Visualization of Genes in Action
The electron microscope reveals individual genes being transcribed into RNA and their RNA being translated into protein. The pictures look remarkably like diagrams based on genetic and biochemical data...
By O. L. Miller
Interstellar Molecules
Twenty-six kinds of molecule have now been discovered In the gas between the stars of our galaxy. Among them are carbon monoxide, water, ammonia, hydrogen sulfide, formaldehyde and methyl alcohol...
By Barry K. Turner
The Asymmetry of the Human Brain
In most people the left cerebral hemisphere plays a dominant role in speech. The specialized functions of the right hemisphere are now emerging. One of these functions is the perception of melody...
By Doreen Kimura
Bicycle Technology
This humane and efficient machine played a central role in the evolution of the ball bearing, the pneumatic tire, tubular construction and the automobile and the airplane
By S. S. Wilson
The Migrations of the Shad
The largest member of the herring family, much prized as a food fish, moves between the sea and its river spawning grounds with remarkable precision. Its main guide appears to be temperature...
By William C. Leggett
The Origins of Number Concepts
Experiments with children indicate that they first become aware of numbers in terms of ordered sequences and only later in terms of quantities. Such findings may give rise to a newer "new math"...