Pierre Curie, inventor and researcher of genius

Pierre Curie was born on 15 May 1859 in Paris. Famous for his research on radioactivity and his talents as an experimenter and instrument designer, his dreamy personality did not predestine him to such a future in this field. In 1903, he and his wife, Marie Sklodowska-Curie, were awarded the Nobel Prize in Physics. For the birthday of this physicist and inventor of genius, we look back at his life and his inventions, which are closely linked to the history of the school.

"If I had the time, I would let myself go and tell all the daydreams I have made"

©Musée Curie (collection ACJC)
Jacques (gauche), Pierre (droite) et leurs parents en 1878 Pierre Curie grew up in a family of the lower middle class with little money. He had an older brother, Jacques, with whom he was very close and who would also become a physicist. Their mother was Sophie-Claire Depouilly and their father, Eugène Curie, was a doctor with a passion for science who would have liked to do research.
A shy and contemplative child, Pierre Curie’s functioning was hardly academic, as his wife Marie confides in her book Pierre Curie: "Pierre’s intellectual qualities were not of the kind that make it possible to quickly assimilate a school curriculum. His dreamy mind did not submit to the regulation of intellectual effort imposed by the school. His difficulty in following this regime was generally attributed to a certain slowness of mind. He himself believed himself to be of slow intelligence and frequently said so.

As education was not compulsory at the time, his parents provided his education themselves. Later, a family friend, Alexandre Bazille, took over and taught him elementary and special mathematics. This developed Pierre Curie’s mental capacities, and he proved to have remarkable abilities in this field. He was also very interested in the natural sciences and was particularly interested in the fauna and flora around him.

Pierre Curie loved nature and often went for walks with his brother, Jacques Curie, to whom he was very close. In the pages of a diary written in 1870, he states: "If I had the time, I would let myself go and tell all the musings I have made. I would also like to describe my delightful valley, all scented with aromatic plants, the beautiful thicket so fresh and humid that the Bièvre flowed through, the palace of the fairies with its hop colonnades, the rocky and red hills of heather on which we were so well."

The invention of quartz-piezoelectricity

For Pierre Curie, it was a need to investigate and understand natural phenomena in order to later establish a satisfactory theory. However, in his time, quantitative scientific data were rare. There were very few measuring instruments, which made it difficult to study phenomena in practice. A lesser-known part of the physicist’s work was therefore concerned with the design of scientific instruments.

In 1880, Pierre Curie and his brother Jacques, then aged 21 and 25 respectively, discovered the phenomenon of piezoelectricity. This is the property of certain crystals, including quartz, to emit small amounts of electricity when compressed or stretched along particular axes of symmetry. This discovery led to an invention called piezoelectric quartz, an instrument for measuring small electrical charges.

Later, this device was used for Pierre and Marie Curie’s work on radioactivity, enabling them to measure, with the naked eye and with precision, the quantity of radiation emitted by uranium salts. They discovered radium (from pitchblende) and polonium. In addition, during the First World War, Paul Langevin and his colleagues used the properties of the piezoelectric effect to develop sonar.

Pierre Curie and the ESPCI

At the end of 1882, the collaboration between the two brothers was interrupted. Jacques Curie was appointed professor of mineralogy at the University of Montpellier, while Pierre Curie became a preparator at the newly created Ecole Municipale de Physique et Chimie Industrielles de la ville de Paris! (EMPCI, i.e. our school today, the ESPCI). He then became head of works and remained so for 12 years. He developed various instruments, including an aperiodic pan balance, in order to carry out high-precision weighing quickly.
From 1891 onwards, the physicist carried out a long series of research projects on magnetism, which he presented as a doctoral thesis to the Faculty of Science in Paris in 1895. He explained his work in this way: "Bodies can be divided, from the point of view of their magnetic properties, into three distinct groups: diamagnetic bodies, weakly magnetic bodies and ferromagnetic bodies. At first sight, these three groups are absolutely clear-cut. The main purpose of this work was to investigate whether there are transitions between these three states of matter, and whether it is possible to make the same body pass gradually through these three states."

Gauche : Pierre Curie Droite : L'expérience de mesure permettant d suivre l'évolution de l'aimantation d'un matériau en fonction de la température.

In this study, Pierre Curie used an electromagnet to measure the temperature at which a material loses its magnetization, called the Curie temperature (or Curie point). The experiment, done at the ESPCI, was reconstructed by Bernard Pigelet, an instrument restorer. It is still accessible in the school and a demonstration of its operation is available :

In 1895, the year of his marriage to Marie Sklodowska, Pierre Curie was appointed to a new professorship at the ESPCI. He was in charge of the theoretical part of the electricity and magnetism course. At the same time, he helped his wife with her research leading to the discovery of radioactivity and developed other measuring devices. In order to measure the electricity produced by the passage of radioactive rays in the air, he designed, for example, a quadrant electrometer.

** Nobel Prize and consecration

In 1900 he was appointed as a lecturer in physics at the Faculty of Sciences of the University of Paris. Subsequently, the Nobel Prize propelled his career and a new Chair of General Physics was created at the Sorbonne for him in 1904. The following year, Pierre Curie ran for the Académie des Sciences and was elected a member on 3 July 1905. At the same time, he was responsible for the laboratory and the organisation of physics teaching at the ESPCI from 1882 until his death in 1906. In his last years, during a conference at the Sorbonne, Pierre Curie confided: "The professors of the School of Physics and Chemistry and the students who have graduated from it constitute a beneficial and productive environment, which has been very useful to me. It is among the former students of the School that we have found our collaborators and friends. I am happy to be able, here, to thank them all."

CRH ESPCI Paris - PSL Gustave Bémont (gauche), Pierre Curie (centre) et Marie Skłodowska-Curie (droite) dans leur laboratoire à l'ESPCI vers 1903