physics 102 chapter 2 and 3

7/30/2019 Physics 102 chapter 2 and 3

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The Church considered Aristotelian natural philosophy to provide support to religious doctrines,

but other naturalist pursuits were considered to be subversive. The Church tended to be

suspicious of natural magic, for example, even though natural magic was simply concerned with

the demonstrable properties of material bodies (such as the ability of magnets to attract iron or the ability

of certain plants or their extracts to cure diseases). One way or another, therefore, the powerful

combination of Aristotelian teachings with Church doctrines tended to exclude direct study

and analysis of nature. The situation began to change during the Renaissance, a period of

tremendous cultural achievement in Europe that began in the early 14th century and ended about

1600. The scientific revolution can be seen as a major respect of the sweeping and far-reaching changes

of the Renaissance. In broad terms the scientific revolution had four major aspects: (1) the development of the

experimental method, (2) the realization that nature obeys mathematical rules, (3) the use of scientific

knowledge to achieve practical aims, and (4) the development of scientific institutions.

Development of the Experimental methodThe Renaissance was the period when the experimental method, still characteristic of science

today, began to be developed and came increasingly to be used for understanding all aspects ofthe physical world. Previously, the natural world had been thought to be comprehensible based on

thoughtful consideration alone. The experimental method holds that understanding comes through hands-on trialand error under controlled conditions. The experimental method was not in itself new it had been a

common aspect of the natural magic tradition from ancient times. For example, all the experimental

techniques used by the English physicist William Gilbert, author of what is generally acknowledged to be the

earliest example of an experimental study of a natural phenomenon ,De Magnete (1600;OfMagnet s,Magnet ic Bodies, andthe Great Magnet o f the Earth, 1890),were first developed by Petrus

Peregrinus, a renowned medieval magus (magician).Experimentation was a major aspect of

the natural magic tradition and was ready for appropriation by Renaissance natural philosopherswho recognized its potential. The experimental methodology used in magic became more

acceptable to Renaissance scholars thanks to the rediscovery of ancient magical writings.Religious opposition to magic had less force after the discovery of various writings allegedlywritten by HermesTrismegistus, Zoroaster, Orpheus, and other mythical or legendary characters. We now

know these texts were written in the early centuries of the Christian Era and deliberately attributed

to such legendary authors, but Renaissance scholars believed they were genuinely ancient

documents. This gave the texts great authority and led to increased respect for magicalapproaches .Increased emphasis on experience and observation complemented the adoption of

manipulative experimental techniques. Andreas Vesalius, innovative professor of surgery at the

University of Padua, claimed to have noticed over 200 errors in Galen's anatomical writingswhen he performed his own dissections. Scholars had previously relied on Galens works

rather than performing their own dissections. Vesaliuss emphasis upon a return to anatomical

dissection led to major discoveries. William Harvey, who was taught by one of Vesalius's successors atPadua, discovered that blood circulates through the body. Similarly, the discovery of numerous new species ofanimals and plants in the New World led to a more empirical approach to natural history. Previously, bestiaries

(books containing collected descriptions of animals) and herbals (books containing collected descriptions of

plants) had included religious symbolism, legends, superstitions, and other non natural lore. Sincethere was no equivalent information about newly discovered species, however, herbal sand bestiaries

compiled after the Renaissance were more likely to record properties based on actual

observation. The advent of printing also played an important part in the transmission of accurateinformation. When the circulation of texts depended upon handwritten copies, illustrations were often crudely

executed by the various scribes who copied the book. Subsequent copies of the copy could be

unrecognizable. In the preparation of a printed edition, however, a skilled illustrator could be called in to

prepare a single illustration that would then be mass-produced. The standard of illustrations improvedimmeasurably. Almost inevitably the illustrations became more realistic and stimulated

a concern for proper observation of natural phenomena .Another important aspect of the new focus on

experimentation and observation (empiricism) was the invention of new observational instruments. The

Italian astronomer Galileo, for example, used the telescope first developed for commercial purposes tomake astonishing astronomical observations. His exciting success stimulated the development of a whole

range of instruments for studying nature, such as the microscope ,thermometer, and barometer.

Mathematization of NatureThe scientific revolution has also been characterized as the period of the mathematization of

the world picture. Quantitative information and mathematical analysis of the physical world

began to be seen to offer more reliable knowledge than the more qualitative and philosophical

analyses that had been typical of traditional natural philosophy.


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The mathematical sciences had their own long history, but thanks to Aristotle's strictures they

had always been kept separate from natural philosophy and regarded as inferior to it. Aristotle's authorityweakened throughout the Renaissance, however, as the rediscovery of the writings of other ancient Greek

philosophers with views widely divergent from those of Aristotle, such as Plato, Epicurus, and the Stoics, made it

plain that he was by no means the only ancient authority. As scepticism became credible in light of the

remarkable exposures of the failings of traditional intellectual positions, mathematics became anincreasingly powerful force. Mathematicians claimed to deal with absolute knowledge, capable of undeniable

proof and so immune from sceptical criticisms. The full story of the rise in status of mathematics is complex

and crowded. Notable contributors included Polish astronomer Nicolaus Copernicus, who claimedthat, for no other reason than that the mathematics indicated it, Earth must revolve around the Sun, and

German astronomer Johannes Kepler, who reinforced this idea with astronomical measurements

vastly more precise than any that had previously been made. Copernicus s moving Earthdemanded a new theory of how moving bodies behave. This theory of motion was effectively

initiated as a new mathematical science by Galileo and reached its pinnacle a few decades later

in the work of Isaac Newton.

Practical Uses of Scientific KnowledgeExperimentalism and mathematization were both stimulated by an increasing concern that

knowledge of nature should be practically useful, bringing distinct benefits to its practitioners, itspatrons, or even to people in general. Apart from supporting dubious medical ideas, the only use

to which natural philosophy had been put throughout the Middle Ages was for bolstering

religion. During the scientific revolution the practical usefulness of knowledge, an assumption

previously confined to the magical and the mathematical traditions, was extended to natural philosophy. To alarge extent this new emphasis was a result of the demands of new patrons, chiefly wealthy

princes, who sought some practical benefit from their financial support for the study of nature.

The requirement that knowledge be practically useful was also in keeping, however, with theclaims of the Renaissance humanists that thevit a act iva(active life) was contrary to the

teachings of the Church morally superior to the vit a contemplat iva(contemplative life) of the

monk because of the benefits an active life could bring to others. The major spokesman for this new focusin natural philosophy was Francis Bacon, one-time Lord Chancellor of England. Bacon promoted his

highly influential vision of a reformed empirical knowledge of nature that he believed would

result in immense benefits to mankind.

development of Scientific InstitutionsFinally, the scientific revolution was also a period during which new organizations

and institutions were established for the study of the natural world. While the universities stilltended to maintain the traditional natural philosophy, the new empirical, mathematical, and

practical approaches were encouraged in the royal courts of Europe and in meetings of like-

minded individuals, such as the informal gatherings of experimental philosophers in Oxford andLondon that occurred during the 1650s. The Royal Society of London was established on a

formal basis in 1660 by attendees of those earlier gatherings. Although nominally under the

patronage of Charles II, the Royal Society received no financial support from the monarchy. A

similar French society, theAcademies des Sciences de Paris, however, was set up by Jean-Baptiste Colbert, Louis XIV's

controller-general of finance, and its fellows were paid from the treasury. Whatever their precise constitution, the

proliferation of collaborative scientific societies testifies to the widespread recognition that, asBacon wrote, knowledge is power, and knowledge of nature is potentially extremely powerful.

People of ScienceResearch the birth and death information, schooling, contributions, work information and awards of the

following persons; Plato, Socrates, Aristotle, William Gilbert, Galileo Galilie, Isaac Newton,Nicolaus Copernicus ,Johannes Kepler, and Tycho BraheB.


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Definition, History, People and Branches of Physics

Definition of Physics-is the branch of science that deals with matter and energy, and its

interactions;-matter-is anything that occupies space (may have volume) and has mass (matter has

quantity); energy is the capacity to do work.

Branches of Physics-Divisions: Classical Physics-

physics branches under classical physics are those that developed and were recognized before 1900

e.g. optics, acoustics, mechanics, thermodynamics, astronomy, electricity, magnetism, electromagnetism;Modern Physics physics branches under modern physics are those that developed during 20

the century to present e.g. quantum physics, relativistic physics plasma physics, elementary

particle physics, solid state physics, condensed matter, molecular physics ,atomic physics, andnuclear physics

Father of Classical Physics-ISAAC NEWTON

Father of Modern Physics -ALBERT EINSTEIN

History of PhysicsPhysics is closely related to the other natural sciences and, in a sense, encompasses them.

Chemistry, for example, deals with the interaction of atoms to form molecules; much of moderngeology is largely a study of the physics of the earth and is known as geophysics; and astronomy

deals with the physics of the stars and outer space. Even living systems are made up of

fundamental particles and, as studied in biophysics and biochemistry ,they follow the same types

of laws as the simpler particles traditionally studied by a physicist. The Babylonians, Egyptians,and early Mesoamericans observed the motions of the planets and succeeded in predicting

eclipses, but they failed to find an underlying system governing planetary motion. Little was

added by the Greek civilization, partly because the uncritical acceptance of the ideas of the major philosophersPlato and Aristotle discouraged experimentation .Some progress was made, however, notably in

Alexandria, the scientific center of Greek civilization. There, the Greek mathematician

and inventor Archimedes designed various practical mechanical devices, such as levers andscrews, and measured the density of solid bodies by submerging them in a liquid. Other

important Greek scientists were the astronomer Aristarchus of Smos, who measured the ratio of

the distances from the earth to the sun and the moon; the mathematician, astronomer, and geographerEratosthenes, who determined the circumference of the earth and drew up a catalog of stars; the astronomer

Hipparchus, who discovered the precession of the equinoxes; and the astronomer, mathematician, and geographer

Ptolemy, who proposed the system of planetary motion that was named after him, in which the earth was the

center and the sun, moon, and stars moved around it in circular orbits In the middle ages, littleadvance was made in physics, or in any other science, during the Middle Ages, other than the

preservation of the classical Greek treatises, for which the Arab scholars such as Averros and Al - Quarashi,the

latter also known as Ibn al -Naf

s, deserve much credit. The founding of the great medieval

universities by monastic orders in Europe, starting in the 13th century, generally failed toadvance physics or any experimental investigations. The Italian Scholastic philosopher

and theologian Saint Thomas Aquinas, for instance, attempted to demonstrate that the works of

Plato and Aristotle were consistent with the Scriptures. The English Scholastic philosopher and

scientist Roger Bacon was one of the few philosophers who advocated the experimental method.

physics 102 chapter 2 and 3

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