History Of Physics
Physics began when man first started to study his surroundings.
Early
applications of physics include the invention of the wheel and of
primitive
weapons. The people who built Stone Henge had knowledge of physical
mechanics in
order to move the rocks and place them on top of each other. It
was not until
during the period of Greek culture that the first systematic
treatment of
physics started with the use of mechanics. Thales is often said
to have been the
first scientist, and the first Greek philosopher. He was an
astronomer, merchant
and mathematician, and after visiting Egypt he is said
to have originated the
science of deductive geometry. He also discovered
theorems of elementary
geometry and is said to have correctly predicted an
eclipse of the sun. Many of
his studies were in astronomy but he also
observed static electricity.
Phythogoras was a Greek philosopher. He
discovered simple numerical ratios
relating the musical tones of major
consonances, to the length of the strings
used in sounding them. The
Pythagorean theorem was named after him, although
this fundamental statements
of deductive geometry was most likely first an idea
from Egyptian methods of
measurements. With the help of his followers he
discovered that the earth was
a sphere, but he did not believe it revolved
around the sun. Democritus was
the leader of a group called Atomists. Although
they were unable to prove
that matter was made up of small particles, they were
the first to come up
with the idea. Democritus believed that atoms differed in
size, shape, and
movement but were all made of the same substances. Aristotle
was the most
important scientific philosopher in Greece. He believed that all
matter on
earth consisted of four pure substances or elements, which were earth,
air,
fire, and water. He also believed that the earth was the centre of
the
universe, and that anything beyond the earth consisted of a fifth pure
substance
called quintessence. Archimedes was an inventor and mathematician,
who
discovered several basic scientific principles and developed a number
of
measuring techniques. Ptolemy was an Egyptian astronomer. He developed a
model
for predicting the positions of the sun, moon, stars, and planets.
Like
Aristotle, he believed that the earth was the center of the
universe. Between
400 AD. and 1000 AD. Most educated people in Western
Europe looked to religion
rather than scientific investigation to answer
their questions about the laws of
nature. At the same time Arabic scholars
were correcting Ptolemy system of
astronomy and performing experiments in
optics and mechanics. As trade increased
between Arab countries and western
countries, their work and Greek scientific
documents became available to
western culture. During the 1200's St. Thomas
Aquinas reconciled
Aristotle's beliefs with church principles. During this time
Roger Bacon
an English scholar conducted studies in optics. During the
Renaissance
there were many social, economic and political changes that produced
new
approaches to science. The famous Italian painter Leonardo da Vinci
conducted
studies in motion and hydraulics. The polish astronomer
Nicolaus
Copernicus proposed a system in which the sun was placed at the
centre of the
universe and the earth was one of the planets orbiting the sun.
In the 1600's
Johannes Kepler, a German astronomer constructed a new and
accurate model of the
solar system. Rene Descartes, a French philosopher and
mathematician developed
the concept of inertia ( that objects maintain their
state of motion unless
disturbed ). At this time people began to realise that
the physical world was
governed by natural laws and that it was possible to
discover those laws through
careful measurement under controlled conditions.
Galileo, an Italian physicist
developed a number of telescopes to study the
heavens, and performed laboratory
experiments on the motion of falling
bodies. In the 1600's there was a great
deal of scientific activity. Sir
Isaac Newton, an English scientist, published
his Mathematical Principle of
Natural Philosophy. He developed three laws of
motion and a law of universal
gravitation based on the work of Galileo and
Descartes. He also invented
a new form of mathematics called Calculus. During
the Industrial Revolution
scientific instruments were produced which were more
accurate and enabled
scientists to perform more complicated experiments. People
began specializing
in specific areas such as: Heat and Energy, Light, and
Electricity and
Magnetism. Scientists began to learn that heat was able to do
work. James
Joule, and English physicist, devised a way to calculate how much
work a give
quantity of heat could do. Later a number of Physicists proposed the
Law
of Conservation of Energy (energy can neither be created nor destroyed,
only
transformed from one form to another). In the early 1800's the theory
was
developed that light existed in the form of waves. Physicists believed
that all
space was filled with ether and that light energy was the vibration
of the
ether. There were other development in the study of electricity and
magnetism,
for example Count Alessandro Volta of Italy invented the electric
battery; Andre
Marie Ampere and Hans Christian showed that electricity
and magnetism were
related, and Michael Faraday and Joseph Henry showed how
mechanical energy could
be converted into electrical energy. At the end of
the 1800's many physicists
believed that all the laws concerning the universe
had been discovered. The
first Physicists in Canada taught at universities
and did very little research.
When Ernest Rutherford studied
radioactivity at McGill University, he inspired
other Physicists to do more
research. In 1930 James Hillier helped to build the
first electron microscope
while he was a student at the University of Toronto.
With financial help
from the National Research Council scientists have developed
the CANDU
nuclear power reactor. Gerhard Herzberg received a Nobel Prize for
his
studies of the ways atoms and molecules give off and absorb light. The
Alouette
satellites, which were launched in the 1960’s, have helped
Physicists to study
matter high above the earth's surface. At the turn of the
twentieth century the
understanding of the physical universe changed
completely when Antoine Henri
Becquerel and Wilhelm Roentgen discovered
radioactivity and x-rays. A general,
theoretical picture for the generation
of x-rays emerged after Niels Bohr
developed the first atomic theory. At this
time Physicists realized that they
had to reexamine the philosophical
foundations of their work. In doing so, the
public saw them as intellectuals
who probed the dark mysteries of the universe.
Physical knowledge was
reorganized and the theories of quantum mechanics were
formulated. Up until
this time most Physicists worked at universities mainly
in
German-speaking Europe. Then research moved to new countries where it
was
supported by industry, National Research Council, or private foundations.
Max
Planck, a German physicist, published his Quantum Theory of Energy
Transfer.
Later, Erwin Schrodinger and Werner Heisenberg initiated the
development of the
field of quantum mechanics. Albert Einstein showed how
mass and energy are
related in his famous equation E = mc2. Research in
physics has led to important
advances in technology, for example: in 1947
American physicists invented the
"Transistor" which revolutionized the
electronics industry, and in the
early 1960's physicists produced lasers
which are light amplifying devices and
are valuable tools in areas such as
communications, industry, and medicine.
Governments have become
interested in promoting scientific investigation. The
United States and
the Soviet Union have carried out extensive research on
thermonuclear weapons
and started a space program. Physics has evolved greatly
from when primitive
man devised ways to move heavy objects to the complex
scientific research
that is being done today. Physics has also moved from being
a branch of
Philosophy in Aristotle's day to being a very exact science
today.
Physicists are still seeking knowledge concerning the laws of
nature and the
universe and are involved in many diverse areas of research,
such as,
biophysics, astrophysics, solid-state physics, and genetic
engineering.
Physicists no longer believe, as they once did, that
everything is now known
concerning the universe and are constantly searching
for new truths.