"If I have seen further, it is only by standing on the shoulders of giants." –
Isaac Newton [1]
Physics (from the
Ancient Greek φύσις
physis meaning "
nature") is the fundamental branch of
science that developed out of the study of nature and
philosophy known, until around the end of the 19th century, as "
natural philosophy". Today, physics is ultimately defined as the study of
matter,
energy and the relationships between them.
[citation needed] Physics is, in some senses, the oldest and most basic pure science; its discoveries find applications throughout the
natural sciences, since matter and energy are the basic constituents of the natural world. The other sciences are generally more limited in their scope and may be considered branches that have split off from physics to become sciences in their own right. Physics today may be divided loosely into
classical physics and
modern physics.
§Ancient history[edit]
§Ancient Greece[edit]
The move towards a rational understanding of nature began at least since the
Archaic period in Greece (650–480
BCE) with the
Pre-Socratic philosophers. The philosopher
Thales of Miletus (7th and 6th centuries BCE), dubbed "the Father of Science" for refusing to accept various supernatural, religious or mythological explanations for natural
phenomena, proclaimed that every event had a natural cause.
[2] Thales also made advancements in 580 BCE by suggesting that water is
the basic element, experimenting with the attraction between
magnets and rubbed
amber and formulating the first recorded
cosmologies.
Anaximander, famous for his proto-
evolutionary theory, disputed the Thales' ideas and proposed that rather than water, a substance called
apeiron was the building block of all matter. Around 500 BCE,
Heraclitusproposed that the only basic law governing the
Universe was the principle of change and that nothing remains in the same state indefinitely. This observation made him one of the first scholars in ancient physics to address the role of
time in the universe, a key and sometimes contentious concept in modern and present-day physics.
[citation needed] The early physicist
Leucippus (
fl. first half of the 5th century BCE) adamantly opposed the idea of direct
divine intervention in the universe, proposing instead that natural phenomena had a natural cause. Leucippus and his student
Democritus were the first to develop the theory of
atomism, the idea that everything is composed entirely of various imperishable, indivisible elements called
atoms.
During the
classical period in Greece (6th, 5th and 4th centuries BCE) and in
Hellenistic times,
natural philosophy slowly developed into an exciting and contentious field of study.
Aristotle (
Greek:
Ἀριστοτέλης,
Aristotélēs) (384 – 322 BCE), a student of
Plato, promoted the concept that observation of physical phenomena could ultimately lead to the discovery of the natural laws governing them. Aristotle's writings cover physics,
metaphysics,
poetry,
theater,
music,
logic,
rhetoric,
linguistics,
politics,
government,
ethics,
biology and
zoology. He wrote the first work which refers to that line of study as "Physics" – in the 4th century BCE, Aristotle founded the system known as
Aristotelian physics. He attempted to explain ideas such as
motion (and
gravity) with the theory of
four elements. Aristotle believed that all matter was made up of aether, or some combination of four elements: earth, water, air, and fire. According to Aristotle, these four terrestrial elements are capable of inter-transformation and move toward their natural place, so a stone falls downward toward the center of the cosmos, but flames rise upward toward the
circumference. Eventually,
Aristotelian physics became enormously popular for many centuries in Europe, informing the scientific and scholastic developments of the
Middle Ages. It remained the mainstream scientific paradigm in Europe until the time of
Galileo Galilei and
Isaac Newton.
Early in Classical Greece, knowledge that the Earth is
spherical ("round") was common. Around 240 BCE, as the result
a seminal experiment,
Eratosthenes (276–194 BCE) accurately estimated its circumference. In contrast to Aristotle's geocentric views,
Aristarchus of Samos (
Greek:
Ἀρίσταρχος; c.310 – c.230 BCE) presented an explicit argument for a
heliocentric model of the
Solar system, i.e. for placing the
Sun, not the
Earth, at its centre.
Seleucus of Seleucia, a follower of Aristarchus' heliocentric theory, stated that
the Earth rotated around its own axis, which, in turn,
revolved around the Sun. Though the arguments he used were lost,
Plutarch stated that Seleucus was the first to prove the heliocentric system through reasoning.
In the 3rd century BCE, the
Greek mathematician Archimedes of Syracuse (
Greek:
Ἀρχιμήδης (287–212 BCE) – generally considered to be the greatest mathematician of antiquity and one of the greatest of all time – laid the foundations of
hydrostatics,
statics and calculated the underlying mathematics of the
lever. A leading scientist of classical antiquity, Archimedes also developed elaborate systems of pulleys to move large objects with a minimum of effort. The
Archimedes' screw underpins modern hydroengineering, and his machines of war helped to hold back the armies of Rome in the
First Punic War. Archimedes even tore apart the arguments of Aristotle and his metaphysics, pointing out that it was impossible to separate mathematics and nature and proved it by converting mathematical theories into practical inventions. Furthermore, in his work
On Floating Bodies, around 250 BCE, Archimedes developed the law of
buoyancy, also known as
Archimedes' Principle. In mathematics, Archimedes used the method of exhaustion to calculate the area under the arc of a
parabola with the summation of an infinite series, and gave a remarkably accurate approximation of
pi. He also defined the
spiral bearing his name, formulae for the
volumes of surfaces of revolution and an ingenious system for expressing very large numbers. He also developed the principles of equilibrium states and
centers of gravity, ideas that would influence the Islamic scholars, Galileo, and Newton.
Hipparchus (190–120 BCE), focusing on astronomy and mathematics, used sophisticated geometrical techniques to map the motion of the stars and
planets, even predicting the times that
Solar eclipses would happen. In addition, he added calculations of the distance of the Sun and Moon from the Earth, based upon his improvements to the observational instruments used at that time. Another of the most famous of the early physicists was
Ptolemy (90–168 CE), one of the leading minds during the time of the
Roman Empire. Ptolemy was the author of several scientific treatises, at least three of which were of continuing importance to later Islamic and European science. The first is the astronomical treatise now known as the
Almagest (in Greek, Ἡ Μεγάλη Σύνταξις, "The Great Treatise", originally Μαθηματικὴ Σύνταξις, "Mathematical Treatise"). The second is the
Geography, which is a thorough discussion of the geographic knowledge of the
Greco-Roman world.
Much of the accumulated knowledge of the ancient world was lost. Even of the works of the better known thinkers, few fragments survived. Although he wrote at least fourteen books, almost nothing of
Hipparchus' direct work survived. Of the 150 reputed
Aristotelian works, only 30 exist, and some of those are "little more than lecture notes".
UNTUK MENGETAHUI LEBIH JAUH ARTIKEL INI SILAHKAN KLIK LINK DIBAWAH INI :
) equals the amount of energy added to a system (Q), such as heat, minus the work expended by the system on its surroundings (W).
is the Boltzmann constant (
) and 
is the partition function, i. e. the number of all possible states in the system.
