Download The Atom: Building Blocks of The Universe

The Atom: Building Blocks of The
Universe
By: Daniel, Lauren, Kristen W., Kristen P.
During this presentation we will explain all the
different principles and models, of certain
philosophers, derived to lead us to what we now
know. We will also explain the evolution of
atomic theory. Atoms are unable to be seen by
the naked eye, which is why scientists have
been forced to create theories and conduct
experiments, to obtain some knowledge towards
understanding the complex structure of the
atom.
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Atomism is the theory, that all
the objects in the world are
composed of very small
indestructible particles called
atoms. In other words the
society was built with nothing
more than indivisible building
blocks. The word atomism
derives from the ancient Greek
word atomos which means
"that which cannot be cut into
smaller pieces".
The Four Elements
During the fifth century B.C., according to a Greek
philosopher named Empedocles, all matter is composed
of four elements: Earth, Fire, Air, and Water. Fire and air
are outwardly reaching elements, reaching up and out,
while on the other hand earth and water turn down. He
believed that all these elements were not only physical
manifestations but also spiritual. They were associated
with four Greek gods: Zeus, Hera, Hades, Nestis.
The earliest model of the
atom pictured it as a solid
sphere of positive charge
with negatively charged
electrons embedded in
them like raisins in a
cookie.
John Dalton expanded on
the ideas of the Geek
philosophers. He stated
that atoms had their own
size, shape, and mass
The Plum Pudding model of the atom
was proposed by J.J. Thomson, the
discoverer of the electron in 1987.
The plum pudding model was
proposed in March, 1904 before
the discovery of the atomic
nucleus. In this model, the atom
Is composed of electrons
surrounded by a soup of positive
charge to balance the electron’s
negative charge, like plums
surrounded by pudding. The electrons
were thought to be positioned throughout
the atom, but with many electron structures possible,
particularly rotating rings. Instead of a soup the atom was said
to have a soup of a positive charge.
British physicist Ernest
Rutherford proposed this
model in 1911. The model
described the atom as a
tiny, dense, positively
charged core called a
nucleus, in which nearly
all the mass is concentrated
around which the electrons
circulate at some distance,
much like planets revolving
around the sun. The Rutherford atomic
model has been also called the nuclear
atom. This experiment was basically just a
representation of his gold foil experiment.
The atomic orbital model is
the currently accepted model of how
the electrons are placed around the
nucleus in an atom. It is
Also referred to as the Wave Mechanics
model. In the atomic
orbital model, the atom consists
of a nucleus surrounded by orbiting
electrons. These electrons exist in
atomic orbitals, which a set of quantum
states of the negatively charged
electrons trapped in the electrical field
generated by the positively charged
nucleus. In example they are in a form
that is similar to our solar system.
At the end of 19th century, physicists knew there
were electrons inside atoms, and that the
wiggling of these electrons gave off light and
other electromagnetic radiation. But there was
still a curious mystery to solve. Physicists would
heat up different elements until they glowed, and
then direct the light through a prism...
This is what
Sun iight looks
Like when it is
shown through
a prism.
For an example:
But when scientists looked at the light coming off
Hydrogen only
Of another element, they didn’t see the whole element,
Gives off these
Colors of the
Instead they got bright lines of certain colors, or
Spectrum.
“visible light.”
To explain the spectral line puzzle, Bohr came up with an excellent model of the atom
Which had electrons orbiting around a nucleus. He came up with an extraordinary rule
That electrons can only be in “special” orbits. All other orbits were just not possible.
They could “jump” between these special orbits, however when they did do this they
Would wiggle a little bit which would cause radiation. Which causes bursts of light called
Photons.