Evolution and Wheels In the past, evolutionary biologists contemplating the absence of wheels in nature agreed that the explanation was not undesirability: wheels would be good for animals, just as they are for us. Animals were prevented from evolvin...
Electricity The modern age is an age of electricity. People are so used to electric lights, radio, televisions, and telephones that it is hard to imagine what life would be like without them. When there is a power failure, people grope about in flick...
Creating Colors There are two ways to create colors in a photograph. One method, called additive, starts with three basic colors and adds them together to produce some other colors. The second method, called subtractive, starts with white light (a mi...
Collectibles Collectibles have been a part of almost every culture since ancient times. Whereas some objects have been collected for their usefulness, others have been selected for their aesthetic beauty alone. In the United States, the kinds of coll...
Colds and Age A critical factor that plays a part in susceptibility to colds is age. A study done by the University of ichigan School of Public Health revealed particulars that seem to hold true for the general population. Infants are the most cold r...
Cohesion-tension Theory Atmospheric pressure can support a column of water up to 10 meters high. But plants can move water much higher; the sequoia tree can pump water to its very top more than 100 meters above the ground. Until the end of the ninete...
Coal-fired Power Plants The invention of the incandescent light bulb by Thomas A. Edison in 1879 created a demand for a cheap, readily available fuel with which to generate large amounts of electric power. Coal seemed to fit the bill, and it fueled t...
Chimpanzee The most striking single fact about chimpanzees is the flexibility of their social life, the lack of any rigid form of organization. It represents about as far a departure from the baboon type of organization as one can find among the high...
Children's Numerical Skills People appear to be born to compute. The numerical skills of children develop so early and so inexorably that it is easy to imagine an internal clock of mathematical maturity guiding their growth. Not long after learning t...
Changing Roles of Public Education One of the most important social developments that helped to make possible a shift in thinking about the role of public education was the effect of the baby boom of the 1950's and 1960's on the schools. In the 1920'...
Cells and Temperature Cells cannot remain alive outside certain limits of temperature, and much narrower limits mark the boundaries of effective functioning. Enzyme systems of mammals and birds are most efficient only within a narrow range around 37 ℃...
British Columbia British Columbia is the third largest Canadian province, both in area and population. It is nearly 1.5 times as large as Texas, and extends 800 miles (1,280km) north from the United States border. It includes Canada's entire west coa...
Botany Botany, the study of plants, occupies a peculiar position in the history of human knowledge.For many thousands of years it was the one field of awareness about which humans had anything more than the vaguest of insights. It is impossible to kn...
Bacteria Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rod-shaped bacter...
Archaeology Archaeology is a source of history, not just a humble auxiliary discipline. Archaeological data are historical documents in their own right, not mere illustrations to written texts. Just as much as any other historian, an archaeologist st...
