Niels BohrA Brief History

By: Dusty, Garrett, Jason & Timmay!

Who He Was

• Name: Neils Bohr• Home: Copenhagen,

Denmark• Lived: Oct. 7 1885-

1962• Education: Doctorate

in physics, University of Copenhagen, 1911

Niels Bohr

• Neils Bohr, a Danish Physicist, developed many theories about atoms and their construction during the 19 and 20th century. This lead to many interesting ideas about atomic reactions to the presence of energy and its effects. We still use Bohr’s theories to explain many occurrences in the world around us.

Accomplishments

• 1913: Published theory of atomic structure, based on Rutherford’s pre-existing theory of the atom.

• 1916: Professor of Physics, University of Copenhagen

• 1920: Named director of the newly constructed Institute of Theoretical Physics

• 1922: Won Nobel Prize for physics, for his work on atomic structure

• 1926: He became a Fellow of the Royal Society of London

• 1938: Received the Royal Society Copley Medal

Development of Theories

Energychanges the orbitals that electrons are in

Orbitals are sucessivelylarger as energy

increases

Energy ModelBohr Model 1

Electrons are in different energy levels(shells) around the nucleus

Light isproduced

Atoms can beidentified by spectrum

color

Different energylevels exist

Spectrumis evident

Energy ModelBohr Model 2

Electrons being energized jump to nextenergy level and fall back

Basic ModelRutherford

Positively Charged NucleusNegitivly Charged particles Orbiting Nucleus

Rutherford Model #1

Rutherford Model #2

Bohr’s First Model

The End Of A Long Career• After perfecting his atomic

model, Bohr continued to study physics and chemistry keeping in mind what he and his peers had discovered about the atom. Never neglecting new theories different from his own, Bohr remained open-minded and active in the science world.

• After the war he strove to achieve a society where nuclear energy could be used to benefit the world rather than destroy it. Sadly, he died in 1962.

Article Analysis Autumn has returned to the Northern Hemisphere, bringing with it

longer nights and more auroral displays. But fall is not the only good season for sky watchers. Historically, both spring and fall host frequent auroral activity. While scientists are still figuring out the reasons for this, make sure you take some extra time this season to check your skies for one of nature's most beautiful displays.

"We've known about this seasonal effect for more than 100 years," says Dennis Gallagher of NASA's Marshall Space Flight Center. "Some aspects of it are understood, but not all."

Aurorae occur when solar particles stream off of the sun and interact with Earth's magnetic field. We are protected from most of the solar wind due to Earth's magnetosphere. The sun's magnetosphere extends millions of miles out into space extending beyond all the planets. The two magnetospheres bump up against each other at the magnetopause, or the outer edge of Earth's magnetosphere. Only when a large influx of solar particles batters the magnetopause do those particles get excited and begin to glow, beginning at the poles and extending farther down

toward the midlatitudes during large solar storms.

Bohr’s Explanation

“It has been presented to me that particles from the sun, known as solar wind, float through space and interact with the earth’s magnetosphere, a magnetic barrier that protects us from solar wind. Where the sun’s magnetosphere meets with the earth’s, there is something called a magnetopause. When large amounts of solar wind meet magnetopause there is a transmission of energy to solar particles. When energy reacts with these atoms, their electrons become excited and ‘leap’ from their current energy level to a higher one. This depends on the amount of energy that is present. The energy cannot be sustained, therefore, the electrons must fall back to their previous energy level. This is an obvious change in energy and the result is seen as light, in multiple frequencies, being emitted. These frequencies depend on both the amount of energy and the atoms being affected. We see these different energy levels as different colours of bright light in the sky known as Aurora Borealis, or more commonly known as The Northern Lights, due to the latitudes where they are most brightly seen.” -Based on ideas of Dr. Niels Bohr.