Grp. Presentation (Bohr, Rutherford and Hau) Members: Cuisia, Marie Camille Agbunag, Nikka Aguirre, Patricia Chua, Selena Kyle Cordero, Cristina Marie Gambalan, Wendy Joaquin, Mary Joy Oliquino, Samantha

1. ATOMIC STRUCTURE
Probing the Atom

2. Sir Ernest
Rutherford
(1871-1937)

3. He is a New Zealand-
born British chemist and physicist who
became known as the father of nuclear
physics. In early work he discovered the
concept of radioactive half-life, proved
that radioactivity involved the
transmutation of one chemical element to
another, and also differentiated and
named alpha and beta radiation, proving
that the former was
essentially helium ions. This work was
done at McGill University in Canada. It is
the basis for the Nobel Prize in
Chemistry he was awarded in 1908 "for
his investigations into the disintegration
of the elements, and the chemistry of
radioactive substances"

4. In 1911, Rutherford and his
coworkers discovered that the
alpha particles were helium atoms
with their electrons removed.
They were positive and very
massive compared to the electron.

5. They focused a stream of high-speed alpha particles on a thin gold foil
and observed how they would be scattered after passing through the foil.
Fig. 1: Rutherford's experiment

6. If Thomson’s model was correct, the alpha
particles with their high-speed and heavy mass
would all pass through the gold foil largely
undeflected.
To their surprise, they observed that, in fact,
most of the particles went straight through but
there were a few that were scattered at wide
angles and there were some, although fewer still,
that were deflected by very large angles, and
some occasional ones which practically bounced
back to the source.

7. Based on these observations, they
dismissed Thomson’s raisin bread
model and proposed the ff:
The fact that most alpha particles
were able to go through the foil
implies that the gold atoms in the
foil must be empty space.
An atom has a core that is very
small.
The negatively charged electrons
move around the nucleus and occupy
most of the volume of the atom.

8. Fig. 1.2: The nuclear model of atom

9. Niels Bohr
(1855-1962)

10. He was a Danish physicist who made
foundational contributions to
understanding atomic structure and quantum
mechanics, for which he received the Nobel
Prize in Physics in 1922.Bohr mentored and
collaborated with many of the top physicists
of the century at his institute in Copenhagen.
He was part of a team of physicists working
on the Manhattan Project. Bohr married
Margrethe Nørlund in 1912, and one of their
sons, Aage Bohr, grew up to be an important
physicist who in 1975 also received the Nobel
Prize. Bohr has been described as one of the
most influential scientists of the 20th century.

11. In view of Rutherford’s model, he
assumed that the prevailing laws of
physics at that time were not sufficient
to describe the atom. He proposed that
the electrons move in orbits around the
nucleus but only orbits of certain radii,
corresponding to certain definite
energies, are permitted. An electron in
a permitted orbit has a specific energy
and is said to be in an ‘allowed’ energy
state. An electron in an allowed energy
state will not radiate energy and
therefore will not be spiral to the
nucleus.

12. Fig. 2: Bohr’s Model

13. Lene Vestergaard
Hau
(1959-present)

14. Was born in Denmark, on November 13, 1959)
is a Danish physicist. In 1999, she led a Harvard
University team who, by use of a superfluid,
succeeded in slowing a beam of light to about
17 metres per second, and, in 2001, was able to
momentarily stop a beam.
In 1989, Hau accepted a two-year appointment
as a postdoctoral fellow at Harvard University.
She received her degree from the University of
Aarhus in Denmark in 1991. Her formalized
training is in theoretical physics but her interest
moved to experimental research in an effort to
create a new form of matter known as a Bose-
Einstein condensate. In 1991 she joined the
Rowland Institute for Science at Cambridge as a
scientific staff member. Since 1999 she has held
the Gordon McKay Professor of Applied Physics
and Professor of Physics at Harvard. She now is
the Mallinckrodt Professor of Physics and
Applied Physics at Harvard.

15. Dr. Hau’s scientific and service contributions have been recognized through
honors that include:
 the MacArthur Fellow 2001–2006;
 the NKT award, awarded by the Danish Physical Society, 2001;
 the Ole Rømer Medal, awarded by the president of the University of
Copenhagen, 2001;
 an Honorary Degree, Æreshåndværker Kjøbenhavns Håndværkerforening,
awarded in the presence of Her Majesty, Queen Margrethe II of Denmark,
Copenhagen, 2001;
 recipient of the Samuel Friedman Rescue Award, awarded by the Friedman
Foundation, University of California, Los Angeles, 2001;
 recipient of the Year 2000 Award from the Top Danmark Foundation,
Copenhagen Denmark, 2000;
 recipient of the J. C. Jacobsen 200 Year Anniversary Award, awarded by the
Carlsberg Foundation, Denmark, 1989;
 recipient of the Research Fellowship, 1986–1989, awarded by the Faculty of
Sciences, University of Aarhus, Denmark.
Dr. Hau recently was awarded an honorary appointment to the Royal Danish
Academy of Sciences and Letters and was elected a foreign member of the
Royal Swedish Academy of Sciences in 2008.
She received in 2010 Danes Worldwide's annual awards "Årets
Verdensdansker" [Best World Dane] because she, according to Danes
Worldwide emphatically and persistently has put Denmark on the world map.

16. MEMBERS:
 Cuisia,Marie Camille
 Agbunag, Nikka
 Aguirre, Patricia
 Chua, Selena Kyle
 Cordero, Cristina Marie
 Gambalan, Wendy
 Joaquin, Mary Joy
 Oliquino, Samantha