harden metals. Copper workers discovered that by combining
copper with tin, they could create bronze, a much harder and
more useful metal that defi ned a historical period, the Bronze
Age. Later scientists discovered that they could convert iron,
an abundant but somewhat soft metal, into hard and durable
steel by the addition of carbon.
Th e earth also provided abundant building materials.
Th e earliest structures were built with logs, reeds, and mud
bricks, but in time people learned to quarry stone such as
marble, limestone, and sandstone to make buildings. Along
the way they discovered principles for engineering these
buildings and in some cases developed sophisticated math-
ematics to help them.
Early farmers became chemists and botanists by learn-
ing how to domesticate crops, cultivate them, store them,
and convert them into food. Chemistry, for example, enabled
them to convert milk from livestock into cheese. Perhaps one
of t he mo s t s uc c e s s f u l pl a nt-bre e d i n g pro g r a m s i n h i s tor y w a s
carried out by the ancient Mesoamericans, who domesticated
maize (corn) from a wild plant. Other farmers became chem-
ists when they learned that the dung from their domesticated
animals or from animals such as bats promoted crop growth
or that burning the stubble from last year’s crop provided the
soil with nutrients that encouraged this year’s crop.
Th is leads to fi re, the second element. Ancient civiliza-
tions learned to use fi re not only for warmth and light but for
other purposes as well. Ancient miners, for example, learned
to crack stone during the quarrying process by building a fi re
next to the rock to heat it and then dousing the rock with cold
water. Th e rapid temperature changes cracked the rock, mak-
ing it easier to mine. Th ey also learned to create blast furnaces
that achieved the high temperatures they needed to refi ne
and melt metal ores. Meanwhile, ancient pottery makers were
making detailed scientifi c observations about materials that
would work best for clay pots, substances that could be used
as dyes for coloring the pots, and ways to fi re and glaze the
pots to make them more durable. Th ey also learned to make
such materials as glass, using silica (sand) and fi re, and to use
minerals mined from the earth to make decorative objects.
With regard to air, ancient civilizations observed the
power in a gust of wind and decided that they could put the
air to work. Th is led to at least two primary developments.
One was to attach sails to boats, giving these boats far greater
range for purposes of exploring, trading, and conquest. Th e
other was the development of the windmill, allowing ancient
farmers to pump water, irrigate land, and thresh grain in far
greater amounts and with much greater effi ciency. Mean-
while, ancient astronomers were looking into the heavens and
observing regularities in the movements of the sun, moon,
and stars.
Water posed a particular problem for ancient civiliza-
tions, particularly those that settled near rivers. Th e ancient
Egyptians, for example, found their livelihoods tied to the
Nile River and the thin strip of fertile soil along its banks.
Th e problem they faced was that the river fl ooded each year.When the fl oodwaters receded, they left behind a great deal
of fertile silt. In ensuing dry months, however, the ground
dried out, threatening the survival of the crops. Out of ne-
cessity, the ancient Egyptians developed skills as hydrologists
and engineers. Th ey learned to build systems of dikes, canals,
dams, and storage grounds for water, which could then be
released when necessary to irrigate crops. In order to be-
come engineers and build these facilities, they had to acquire
knowledge in materials science, construction techniques, and
the like, all of which required some ability in mathematics
and measurement.
Th e modern world takes for granted an extensive base
of information about the physical world and how it works.
Ancient civilizations had to discover this information out of
nothing. Without their scientifi c achievements it is unlikely
that they would have survived in any appreciable numbers.
Had that happened, the world might still be a frightening
place of pure mystery and magic.AFRICA
BY TOM STREISSGUTH
Ancient Africans viewed the natural world and all that
occurred within it as expressions of the unseen realm of
spirits. Events on earth were predetermined, the result of
malevolent or benign forces that acted at whim. Humans
could never hope to control the fertility of the soil, the com-
ing of the rains, the occurrence of drought or illness, or the
seasonal fl ood of rivers and lakes. Th ey could only propitiate
the spirits of the natural world, look for guidance in signs
appearing on the earth and in the heavens, and seek out the
environments that were best suited to their own survival.
Th ey did not pursue science for its own sake or by the mod-
ern method of testing theories in controlled experiments.
Ancient chemistry, botany, metallurgy, physics, medicine,
astronomy, and so on came in the form of practical knowl-
edge applied to everyday needs: growing food, fi ghting wars,
curing the sick, or relieving the pain of giving birth. Fur-
ther, there was no sharp line between religious and scientifi c
practices, since a spiritual outlook governed virtually all as-
pects of life. Generally speaking, any activities that ancient
Africans carried out for the purpose of enhancing their
livelihood and manipulating their environment should be
considered science.TOOLMAKING: THE FIRST APPLIED SCIENCE
Early human beings needed to master the environment in or-
der to fi nd food, protect themselves from hostile strangers,
and hide from dangerous animals. A vital ingredient in these
endeavors was the use of tools. Th e shaping of stone imple-
ments, according to archaeologists, fi rst occurred in Africa.
At Olduvai Gorge (in present-day Tanzania) primate species
probably ancestral to modern humans were using sharp rocks
as tools some 2.6 million years ago. Th ey may have created
these rudimentary tools simply by cracking brittle stones to922 science: Africa0895-1194_Soc&Culturev4(s-z).i922 922 10/10/07 2:30:26 PM