Scientific Revolution

What was it?

• Changes in the way Europeans thought– Systematic doubt– Empirical, sensory

verification– Abstraction of human

knowledge into separate sciences

– View that world works like a machine

When was it?

• Like the Renaissance, no set beginning date– Newton (1700s)?– Galileo (1600s)?– Da Vinci (1500s)?– Earlier (re-discovery of

Aristotle, in 1200s)?

Why did it happen?• Trade with Islam brought

Europeans the works of Aristotle• Development of Scholasticism

– 1100s-1500s– resolve contradictions beteewn

church, ancients thru Aristotlean deductive logic

• Alchemy (prim. Chemistry)• Humanism

– Introduction of Greek (Plato) classics, to Europe

– Ultimately led to Prot. Reformation

• Da Vinci’s view of universe, which turned Medieval beliefs upside down– Inquisitive, for it’s own sake

Astronomy: The Greeks• Most believed in a Earth

centered (“geocentric”) universe– Look at the stars…

– Cycles!

– Problem w/ geocentric: planets moved in circles, but also moved backwards (precession)

– Problem w/ heliocentric: if Sun at center, Earth moves 1000s of MPH (jump up – where land?)

Precession (Epicycles)

Astronomy: Copernicus (1473-1543)

• In year of his death, published On the Revolutions of the Heavenly Spheres

• Proposed sun centered (“heliocentric”) universe– Theory “fixed” math

problems in geocentric system

– Argued God was in sun (spiritual fix)

Astronomy: Arabic Numbers• Through most of

middle ages, everyone used roman numerals– Hard to do math– Challenge: Addition!

• Arabs used place number system– Advantage: easy to

calculate– And calculate, they did!

Other Astronomers• Tycho Brahe (1546-

1601)– Performed years worth

of stellar observations– Result? Proved

Copernican system right• Johannes Kepler

(1571-1630)– Proved orbits were

elliptical, not circular– His model perfectly

predicted planetary motions

– His book, New Astronomy, inspired Galileo

Galileo Galilei (1564-1642)

• Referred to as the “Father of Modern Astronomy”

• First to use telescope to observe the sky– Mtns on Moon!– 5 moons around Jupiter

• Published findings in The Starry Messenger

• Masterwork: Dialogues on the Two Chief Systems of the World

• Written in style of a conversation, it insisted universe operated along mathematical principles

Galileo and the Church

• Galileo, a professor, taught his students of his findings

• In 1616, Cardinal Roberto Bellarmino personally ordered Galileo NOT to teach the Copernican system; he agreed, and only talked about the hypothesis of heliocentrism

• In 1632, he published “Dialogue Concerning the Two Chief World Systems”, a criticism of the Geocentric model

• In 1632, he was ordered to appear before the Inquisition, accused of heresy

Galileo and the Inquisition• Why did the Church care

about Galileo?– Psalms 93: “the world is

firmly established, it cannot be moved”

– Psalms 104: “the LORD set the earth on its foundations; it can never be moved”

– Ecclesiastes 1: “and the sun rises and sets, and returns to its place”

• In his Dialogues, Galileo personally offended the Pope, a former supporter

Decision of the Inquisition• Galileo was required to recant, or deny, his

heliocentric beliefs; this was considered heretical• Galileo was ordered imprisoned; later, he was

put under house arrest• His “Dialogue” was banned, and any further

writing of his was forbidden

Scientific Method• Francis Bacon (1561-

1626) advocated inductive thinking– Observe natural phenomena– Derive general principles to

explain observations

• His idea led to the formal scientific method– Gather evidence– Collect additional data

through experimentation– Test hypothesis

Isaac Newton (1643-1727)• English physicist, natural

scientist, astronomer, mathematician

• Believed in “clockwork universe”

• 1687 Masterwork = The Mathematical Principles of Natural Philosophy (known as Principia Mathematica)– Universe was mechanistic– Universe explained thru math– Laid out attraction of gravity– Laid out 3 laws of motion

Biology• Antony van

Leeuwenhoek (1632-1723) (“Father of microbiology”)– Use of microscope (up

to 500x!) to examine plants, animals

– Named cells

• Carolus Linnaeus (1707-1778)– Systema Naturae:

catalogued all creatures in a system

Chemistry• While people were discovering

chemical reactions, no one could explain how they worked

• Henry Cavendish: discovered hydrogen

• Joseph Priestley: discovered oxygen

• Europeans began moving away from belief that all matter was made of 4 elements (Fire, Air, Water, Earth)

• Antoine Lavoisier: law of conservation of mass

Electricity

• Stephen Gray, 1729: proved electricity could be transmitted through metal wires

• 1745: Leyden jar (first electrical storage device)

• Ben Franklin, 1749: lightning = electricity

MedicineDissection of human

cadaver by Belgian

physician Andreas

Vesalius (1514-1564)

• Dissections led to investigation of body– Anatomy– Circulation of blood– Inoculation– Vaccination

• Proposal that body was a natural system, followed predictable and rational ways

• Man was mechanistic!

The End

Newton’s apple tree