ARCHIMEDES
Archimedes was a Greek mathematician and philosopher
who lived from 287 to 212 B.C. According to legend, he was asked by the emperor
to determine whether a crown was made of pure gold or a mixture of gold and
less valuable metals, such as silver and copper. After receiving this
assignment, Archimedes was taking a bath one day when he noticed that the
deeper his body sank into the water, the more water overflowed the bath, and
his body seemed to weigh less the more it was submerged. He concluded that the
apparent loss of weight of an object submerged in a liquid is equal to the
weight of the liquid it displaces. This principle, now named after him.
Having previously observed that the volume of an
object determines the volume of the liquid it displaces, he would weigh the
crown and the same weight of gold both immersed in water in separate
containers. Because every object has a different ratio of weight to volume, or density,
the crown (if it was not made entirely of gold) and the pure gold that weighed
the same amount in air would have different weights in water because they would
displace different volumes of water. Supposedly, Archimedes was so excited by
his brilliance that he ran from the bath shouting “Eureka”-the Greek word for
“I have found it!”.
Chemistry is largely an experimental science. Like
Archimedes’ discovery, most advances in chemistry are the results of
observations and experiments, although the setting is usually in a laboratory.
MARIE CURIE
More than a century ago scientists became interested
in the radioactivity phenomenon. A young graduate student named Marie
Sklodowska Curie, with her husband Pierre Curie as her coworker, chose as the
subject of her doctoral research radioactive uranium ore. In 1898 the Curies
isolated a new element, which they named polonium after Marie’s native country
of Poland. Four months later, they discovered radium, another radioactive
element.
In their makeshift laboratory in a shed, Marie and
Pierre processed tons of pitchblende (a uranium oxide ore) to obtain just 0.1 g
of the fluorescent blue substance at their bedside, and they loved to visit the
shed at night to look at the luminous test tubes glowing like fairy lights. The
unusual properties of radium made it the most important element to be
discovered since oxygen. Marie Curie’s thesis was hailed by many scientists as
“the greatest contribution to science ever made by a doctoral student.”
Along with Becquerel (the discoverer of
radioactivity), the Curies were awarded the Nobel Prize in Physics in 1903-the
same year in which Marie received her doctoral degree. By then, Marie Curie was
a household word, the world’s most famous scientists nevertheless encountered
hostility and discrimination in the scientist community. She was denied admission
to the French Academy of Sciences by one vote because she was a woman!
Marie Curie was the first woman to win a Noble Prize,
the first person to win two Nobel Prize (the second in chemistry in 1911), and
the first Noble Prize winner to have a child go on to win a Noble Prize. Today
the element with the atomic number 96, curium (Cm), is named in Marie Curie’s
honor.
