Henri Becquerel

1. Antoine Henri Becquerel was
born in Paris on December 15,
1852. He was a member of a
distinguished family of scholars
and scientists. His father,
Alexander Edmond Becquerel,
was a Professor of Applied
Physics and had done research
on solar radiation and on phos-
phorescence, while his grandfa-
ther, Antoine César, had been a
Fellow of the Royal Society and
the inventor of an electrolytic
method for extracting metals
from their ores. Becquerel
was a third generation scien-
tist. Written accounts of
that period of his life suggest
there was a close relationship
between father and son in the
passing on of the scientific
tradition. Two previous gen-
erations of scientists gave
Henri Becquerel the drive to
further enlighten the world
through scientific research.
Antoine Henri Becquerel
Early Life
Educational Background
Becquerel entered the
Polytechnic in 1872, then
the government depart-
ment of Ponts-et-
Chaussées in 1874, becom-
ing an engineer in 1877 and
being promoted to Chief
Engineer in 1894. In 1888
he acquired his doctorate
with his dissertation on the
absorption of light by crys-
tals. From 1878 he had held
an appointment as an Assis-
tant at the Museum of
Natural History, taking over
from his father in the Chair
of Applied Physics at the
Conservatoire des Arts et
Metiers. Then in 1892 he was
appointed Professor of Ap-
plied Physics in the Depart-
ment of Natural History at
the Paris Museum. He then
later became a Professor at
the Polytechnic in 1895.

Antoine Henri
Becquerel

2. Following a discussion
with Henri Poincaré on
the radiation which
had recently been dis-
covered by Röntgen (X
-rays) and which was
accompanied by a type
of phosphorescence in
the vacuum tube, Bec-
querel decided to in-
vestigate whether
there was any connec-
tion between X-rays
and naturally occurring
phosphorescence.
He had inherited from
his father a supply of
uranium salts, which
phosphoresce on expo-
sure to light. When the
salts were placed near
to a photographic plate
covered with opaque
paper, the plate was
discovered to be
fogged. The phenome-
non was found to be
common to all the ura-
nium salts studied and
was concluded to be a
property of the ura-
nium atom. Becquerel
concluded "that the
phosphorescent sub-
stance in question
emits radiation which
penetrates paper
opaque to light." Ini-
tially he believed that
the sun's energy was
being absorbed by the
uranium which then
emitted X rays.
Further investigation,
on the 26th and 27th
Contributions to Science
such as the sun. Bec-
querel had discovered
radioactivity, the spon-
taneous emission of ra-
diation by a material.
Later, Becquerel demon-
strated that the radia-
tion emitted by uranium
shared certain charac-
teristics with X rays
but, unlike X rays, could
be deflected by a mag-
netic field and there-
fore must consist of
charged particles. For
his discovery of radioac-
tivity, Becquerel was
awarded the 1903 Nobel
Prize for physics.
of February, was de-
layed because the
skies over Paris were
overcast and the ura-
nium-covered plates
Becquerel intended to
expose to the sun were
returned to a drawer.
On the first of March,
he developed the pho-
tographic plates ex-
pecting only faint im-
ages to appear. To his
surprise, the images
were clear and strong.
This meant that the
uranium emitted radia-
tion without an exter-
nal source of energy
Page 2
Antoine Henri Becquerel
William Rontgen.
Inset Photo:
Radiograph of Frau
Rontgen’s Hand
Stamp made in honor of
Becquerel’s Achievements
“Decisiveness is often
the art of timely
cruelty.”
- Henri Becquerel

3. The discovery of radioac-
tivity has help us a great
deal. We now know of ways
to protect ourselves from
it. We have even found
ways to use it in medicine.
Radioactivity and radiation
are used in cancer treat-
ment and for scans and x
rays. A unit has been
named after him, which
helps us when doing
calculations. One Becquerel
(Bq) is one disintegration per
second of a radioactive sub-
stance.
Marie also has a unit named
after her:
One Curie is the activity of a
substance which undergoes
3.7x10
10
disintegrations per
second.

it’s name. Marie and her
husband Pierre went on to
discover the elements
known as radium and polo-
nium. They also shared to
Nobel Peace Prize with
Becquerel in 1903.
Marie Curie was actually
the student of Antoine
Henri Becquerel. Al-
though Becquerel discov-
ered the phenomenon of
radioactivity, it was
Marie Curie who gave it
Impact on Our Lives
Interesting Facts
Other Facts About Becquerel
in 1889 and succeeded
Berthelot as Life Sec-
retary. He was also a
member of the Accade-
mia dei Lincei and of
the Royal Academy of
Berlin, amongst others.
He was made an Officer
of the Legion of Honour
in 1900. He was married
to Mlle. Janin, the
daughter of a civil engi-
neer. They had a son
Jean, born 1878, who
was also a physicist: the
fourth generation of
scientists in the Bec-
querel family. Antoine
Henri Becquerel died at
Le Croisic on August 25,
Becquerel published his
findings in many papers,
principally in the An-
nales de Physique et de
Chimie and the Comptes
Rendus de l'Academie
des Sciences.
He was elected a mem-
ber of the Academie
des Sciences de France
Page 3

Seamour Sheep Comic on
Radiation
Marie and
Pierre Curie
“Nothing in life is to be
feared. It is only to be
understood.”
- Marie Curie

4. Excellence, Access. (2009, December 4). Radioactivity: historical figures.
Retrieved from http://www.accessexcellence.org/AE/AEC/CC/
historical_background.php

From Nobel Lectures, Physics 1901-1921, Elsevier Publishing Company, Am-
sterdam, 1967

Heaven, S. (Artist). (2008). Seamour sheep. [Web]. Retrieved from http://
www.seamoursheecom/comics/english/seamour-sheep-61.jpgp.
References


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