DISCOVERERS OF

RADIOACTIVITY

GROUP 1

Antoine Henri Becquerel

• was a French physicist, Nobel laureate, and one of the discoverers of radioactivity. He won the 1903 Nobel Prize in Physics for discovering radioactivity.

• One of those who took the task of looking for other invisible radiation.

In 1896, while investigating phosphorescence in uranium salts, Becquerel accidentally discovered radioactivity.

Investigating the work of Wilhelm Conrad Röntgen, Becquerel wrapped a fluorescent substance, potassium uranyl sulfate, in photographic plates and black material in preparation for an experiment requiring bright sunlight. However, prior to actually performing the experiment, Becquerel found that the photographic plates were fully exposed. This discovery led Becquerel to investigate the spontaneous emission of nuclear radiation.

BECQUEREL’S SETUP

Becquerel wrapped a photographic plate in a thick black pepper

He placed a crystal of the fluorescent uranium salt on top of the paper.

Then he exposed the setup to sunlight.

He found a foggy photographic film, confirming his prediction that the uranylsulfate did emit radiation.

Image of Becquerel's photographic plate which

has been fogged by exposure to radiation from a uranium salt. The shadow of

a metal Maltese Cross placed between the plate and the uranium salt is

clearly visible.

Following his serendipitous discovery of the phenomenon, Becquerel studied further what he called “INVISIBLE PHOSPHORESCENCE”.

For about a year and a half, a young graduate student, MARIE SKLODOWSKA-CURIE, decided to pursue it for her doctoral study.

Marie Curie

was a physicist and chemist of Polish upbringing and, subsequently, French citizenship. She was a pioneer in the field of radioactivity, the first person honored with two Nobel Prizes

• Her achievements include the creation of a theory of radioactivity (a term coined by her), techniques for isolating radioactive isotopes, and the discovery of two new elements, polonium and radium.

• She did several experiments that confirmed Becquerel’s observation. She found that the effects of the Becquerel’s rays were the same regardless of whether the uranium was solid or pulverized, wet or dry, or whether it was in a pure state or combined with other elements.

• She hypothesized that the rays could be emanating from the uranium atoms. To test her hypothesis, she proceeded to look for other radioactive elements.

• In July 1898, Skłodowska–Curie and her husband together published a paper announcing the existence of an element which they named "polonium," in honor of her native Poland, which would for another twenty years remain partitioned among three empires. On 26 December 1898, the Curies announced the existence of a second element, which they named "radium" for its intense radioactivity — a word that they coined.

Ernest Rutherford• British chemist and physicist who

was known as the father of nuclear physics. He discovered that atoms have a small charged nucleus, and thereby pioneered the Rutherford model of the atom, through his discovery of Rutherford scattering with his gold foil experiment. He was awarded the Nobel Prize in Chemistry in 1908. He is widely credited as splitting the atom in 1917 and leading the first experiment to "split the nucleus" in a controlled manner by two students under his direction, John Cockcroft and Ernest Walton in 1932.

Discovery

• He began to study Becquerel’s rays and found that there are at least 2 distinct types of radiation in those rays – one that is easily absorbed, and another which is more penetrating.

• He called the first as alpha (α) radiation and the second one as beta (β) radiation

Alpha and Beta Decay

• In 1903, he was able to show that α rays can be deflected using strong electric and magnetic fields, thus proving that alpha rays were positively charged particles.

• His work with Hans Geiger also helped determine that alpha particles had a charge of +2.

• Finally, Rutherford and Royds captured alpha particles using a setup. The results of such experiment led them to conclude that an alpha particle is the nucleus of a helium atom.

GROUP 1 Joan Dimayuga

Jessica Andales Van Adriane Bulanhagui

Geraldine Talatala Edd-Ghar Valencia

Mary Ann Baluyot

THANKTHANK

YOU!!!!YOU!!!!