MARIE CURIE  1867-1934   Warsaw, Poland
 Pioneer of Radioactivity

 - Discovered Radium and Polonium 1899
 - Coined the word "radioactivity"

 - Thesis RESEARCHED ON RADIOACTIVE SUBSTANCES 1903 ranks among the
   classics of science

 - First to win more than one nobel prize: 1903, 1911, 1935


 The Background Story on Marie and Pierre Curie:

Pierre and Marie Curie are best known for their pioneering work in the
study of RADIOACTIVITY, which led to their discovery in 1898 of the
elements RADIUM and POLONIUM. Marie Curie was born Manya Sklodowska in
Warsaw, Poland, on Nov. 7, 1867. After many impoverished years as a
teacher and governess, she joined her sister Bronia in Paris in order to
study mathematics and physics at the Sorbonne, earning degrees in both
subjects in 1893 and 1894. In the spring of the latter year she met the
physicist Pierre Curie. They married a year later, and Marie subsequently
gave birth to two daughters, Irene (1897) and Eve (1904). 

Pierre Curie, b. May 15, 1859, d. Apr. 19, 1906, obtained his doctorate in
the year of his marriage, but he had already distinguished himself (along
with his brother Jacques) in the study of the properties of crystals. He
discovered the phenomenon of PIEZOELECTRICITY, whereby changes in the
volume of certain crystals excite small electric potentials. Along with
work on crystal symmetry, Pierre Curie studied the magnetic properties of
materials and constructed a torsion balance with a tolerance of 0.01 mg.
He discovered that the magnetic susceptibility of paramagnetic materials
is inversely proportional to the absolute temperature (Weiss-Curie's law)
and that there exists a critical temperature above which the magnetic
properties disappear (CURIE TEMPERATURE). 

Since 1882, Pierre had headed the laboratory at the Ecole de Physique et
de Chimie Industrielle in Paris, and it was here that both Marie and
Pierre continued to work after their marriage. For her doctoral thesis,
Madame Curie decided to study the mysterious radiation that had been
discovered in 1896 by Henri Becquerel. 

With the aid of an electrometer built by Pierre and Jacques, Marie
measured the strength of the radiation emitted from uranium compounds and
found it proportional to the uranium content, constant over a long period
of time, and uninfluenced by external conditions. She detected a similar
immutable radiation in the compounds of thorium. While checking these
results, she made the unexpected discovery that uranium pitchblende and
the mineral chalcolite emitted about four times as much radiation as could
be expected from their uranium content. In 1898 she therefore drew the
revolutionary conclusion that pitchblende contains a small amount of an
unknown radiatiant. In their research over the next year, they discovered
two new spontaneously radiating elements, which they named polonium (after
Marie's native country) and radium. A third element,  actinium, was
discovered by their colleague Andre Debierne. 

They now began the tedious and monumental task of isolating these elements
so that their chemical properties could be determined. In 1903, Marie Curie
obtained her doctorate for a thesis on radioactive substances, and with her
husband and Henri Becquerel she won the Nobel Prize for physics for the
joint discovery of radioactivity. The financial aspect of this prize
finally relieved the Curies of material hardship. 

The following year Pierre was appointed professor at the Sorbonne, and
Marie became his assistant. She was deeply affected when Pierre died after
being struck by a truck on a Paris street. She overcame this blow only by
putting all her energy into the scientific work that they had begun
together. The Sorbonne provided the opportunity by offering her the post
that Pierre had held of lecturer and head of the laboratory. She thus
became the first female lecturer at the Sorbonne, and in 1908 she was
appointed professor. 

For the isolation of pure radium, Marie Curie received a second Nobel
Prize in 1911, this time for chemistry.  During World War I, Madame Curie
dedicated herself entirely to the development of the use of X rays in
medicine. In 1918 she took upon herself the direction of the scientific
department of the Radium Institute, which she had planned with her
husband, and where her daughter Irene JOLIOT-CURIE worked with her 
husband Frederic Joliot. Marie's research for the rest of her life was
dedicated to the chemistry of radioactive materials and their medical
applications. She frequently lectured abroad, and  she labored to establish
international scholarships for scientists. 

Her death, on July 4, 1934, of leukemia was undoubtedly caused by
prolonged exposure to radiation. The work of Marie and Pierre Curie, which
by its nature dealtwith changes in the atomic nucleus, led the way toward
the modern understanding of the atom as an entity that can be split to
release enormous energy.