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.