RadioactivityThe DiscoveryBy:Kaitlin Shorr and Tara Monaghan

Henri Becquerel: Biography

● Full Birth Name: Antoine Henri Becquerel

● Born: December 15, 1852, in Paris, France

● Died: August 25, 1908 ● Field: Nuclear Science Physics● Occupation: physicist● Education: École Polytechnique,

École des Ponts et Chaussées● 1897- researched the newly

discovered x-rays which led him to the phenomenon of radioactivity.

Henri Becquerel’s Scientific Work● Becquerel's earliest work:

was with the concern of plane polarization of light, with the phenomenon of phosphorescence and with the absorption of light by crystals (his doctorate thesis).

● He also worked on the subject of terrestrial magnetism.

● In 1896, his previous work overshadowed his discovery of the phenomenon of natural radioactivity.

Henri Becquerel's Discovery

● 1896: he used naturally fluorescent minerals to study the properties of x-rays.

● He exposed potassium uranyl sulfate to sunlight and then placed it on photographic plates wrapped in black paper.

● He believed that the uranium absorbed the sun’s energy and then emitted it as x-rays.

● A couple days went by and he tested it again by putting the uranium in a closed door with the photographic plate.

● It left a clear strong image on the photographic plate.

● When his experiment was disproved( 26th and 27th of February) he tested anyway and it proved that uranium emitted radiation with the source of the sun.

● He had, after his findings, discovered that uranium could produce a picture on the photographic plate without light, radioactivity.

Becquerel Apparatus ● used an apparatus to show that the radiation he discovered

could not be x-rays. ● x-rays are neutral and cannot be bent in a magnetic field. ● new radiation was bent by the magnetic field so that the

radiation must be charged and different than x-rays. ● when different radioactive substances were put in the magnetic

field, they deflected in different directions or not at all.● showed that there were three classes of radioactivity: negative,

positive, and electrically neutral.

Pierre Curie: Biography

● Born: On May 15, 1859, in Paris, France

● Died: April 19, 1906● Education: Faculty of Sciences at

Sorbonne and got his doctorate the year he married Marie.

● Before he and his brother, Jacques, distinguished themselves in the study of the properties of crystals.

● In 1882, Pierre had headed the laboratory at the Ecole de Physique et de Chimie Industrielle in Paris.

Pierre Curie’s Scientific Work● studied the properties of

crystals○ discovered piezoelectricity

● studied the magnetic properties of materials

● constructed a torsion balance with a tolerance of 0.01 mg

● discovered Weiss-Curie’s Law

● discovered Curie temperature

Marie Curie: Biography

● Born: As Maria Sklodowska in Warsaw, Poland on November 7, 1867

● Died: July 4, 1934● Education: spent many years as a teacher and governess; joined

her sister, Bronia, in Paris to study mathematics and physics at Sorbonne

● earned degrees in both mathematics and physics in 1893 and 94● met physicist, Pierre Curie, and got married (1895)● had two children, Irene (1897) and Eve (1904).

Marie Curies’s Discovery● Marie

○ decided to study the mysterious radiation Becquerel had discovered

○ 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

● detected a similar immutable radiation in the compounds of thorium

● 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

● concluded that pitchblende contains a small amount of an unknown radiating element

• Used an electrometer to search for new substances which uses the level of radioactivity to determine the strength of the current

• discovered two new spontaneously radiating elements, which they name polonium and radium.

• colleague, Andre Debierne, discovered actinium

• began the task of isolating these elements so that their chemical properties could be determined.

Pierre Joins Marie in her work

Awards Won● the Curies and Becquerel

○ Nobel Prize in Physics for the discovery of radioactivity

● Marie Curie ○ Nobel Prize in chemistry for isolating radium

● "Pierre Curie - Biographical." Pierre Curie - Biographical. N.p., n.d. Web. 04 Nov. 2013. <http://www.nobelprize.org/nobel_prizes/physics/laureates/1903/pierre-curie-bio.html>.

● "Henri Becquerel - Facts." Henri Becquerel - Facts. N.p., n.d. Web. 04 Nov. 2013. <http://www.nobelprize.org/nobel_prizes/physics/laureates/1903/becquerel-facts.html>.

● "Pierre and Marie Curie." Pierre and Marie Curie. N.p., n.d. Web. 04 Nov. 2013. <http://chemistry.mtu.edu/~pcharles/SCIHISTORY/Marie_Curie.html>.

● "Marie Curie and the History of Radioactivity." - Online Science. N.p., n.d. Web. 06 Nov. 2013. <http://www.sciencemuseum.org.uk/onlinestuff/stories/marie_curie_and_the_history_of_radioactivity.aspx?page=2>.