The Scientific Revolution

Truth?Truth?

In the Middle Ages, In the Middle Ages, scholars decided scholars decided truth based on the truth based on the Bible or from Bible or from Greek or Roman Greek or Roman texts.texts.

In the Renaissance, In the Renaissance, people questioned people questioned how the universe how the universe worked.worked.

This caused the This caused the Scientific Scientific Revolution.Revolution.

TheThe AristotelianAristotelian View of the UniverseView of the Universe

Aristotle put forth this view of the universe Aristotle put forth this view of the universe in the 4in the 4thth century B.C. century B.C.

This is commonly known as the This is commonly known as the GEOCENTRIC view where a motionless GEOCENTRIC view where a motionless Earth is at the center of the universe while Earth is at the center of the universe while the moon, sun, planets, and stars revolve the moon, sun, planets, and stars revolve around the Earth.around the Earth.

Notice also that it was believed that the Notice also that it was believed that the orbits were circular.orbits were circular.

Ancient astronomers also believed the Ancient astronomers also believed the Earth was composed of “heavy” elements Earth was composed of “heavy” elements while the celestial bodies were composed while the celestial bodies were composed of completely different substances and of completely different substances and thus were weightless, allowing them to thus were weightless, allowing them to orbit the Earth.orbit the Earth.

TheThe CopernicanCopernican HypothesisHypothesis

In the 16In the 16thth century, the Polish monk, century, the Polish monk, mathematician, and astronomer mathematician, and astronomer Copernicus Copernicus (1473-1543)(1473-1543) challenged the challenged the geocentric theory.geocentric theory.

His famous work On the Revolutions of His famous work On the Revolutions of the Heavenly Spheres, held the sun to the Heavenly Spheres, held the sun to be the center of the solar system aka, be the center of the solar system aka, the HELIOCENTRICthe HELIOCENTRICtheory.theory.

His ideas areHis ideas areattacked by religiousattacked by religiousauthorities; authorities; Luther called himLuther called him“the fool who wants“the fool who wantsto turn the wholeto turn the wholeart of astronomyart of astronomyupside down.”upside down.”

1. Nicolaus Copernicus1. Nicolaus Copernicus

1500’s 1500’s

PolishPolish

AstronomyAstronomy

HeliocentricHeliocentric theory – the theory – the earth and earth and planets revolve planets revolve around the sun!around the sun!

Until this time, scholars believed in the Until this time, scholars believed in the geocentric theorygeocentric theory, that everything in the , that everything in the universe revolved around the earth.universe revolved around the earth.

Copernicus’ Copernicus’ theory still theory still didn’t explain didn’t explain why the planets why the planets orbited the way orbited the way they did.they did.

Fearing ridicule Fearing ridicule or persecution, or persecution, Copernicus did Copernicus did not publish his not publish his findings until findings until 1543, the year 1543, the year he died.he died.

Model of our Solar SystemModel of our Solar System

GALILEO GALILEO EVIDENCE FOR HELIOCENTRICISMEVIDENCE FOR HELIOCENTRICISM((OBSERVATIONS OF THE MOONS OF JUPITER)OBSERVATIONS OF THE MOONS OF JUPITER)

1609-16421609-1642

ItalianItalian

Scientist & Scientist & astronomerastronomer

Invented the Invented the telescopetelescope

3. Galileo Galilei3. Galileo Galilei

GALILEO OBSERVED JUPITER AND THE ROTATION OF GALILEO OBSERVED JUPITER AND THE ROTATION OF ITS MOONSITS MOONS

In Italy,In Italy, Galileo Galileo confirmed confirmed Copernicus’ Copernicus’ heliocentric heliocentric theory through theory through the use of his the use of his telescope.telescope.

The Catholic Church warned Galileo, but in 1632 he The Catholic Church warned Galileo, but in 1632 he published a heliocentric book!published a heliocentric book!

The pope called Galileo to Rome to stand trial.The pope called Galileo to Rome to stand trial.

Under the threat of torture and excommunication, Under the threat of torture and excommunication, Galileo knelt before the cardinals and read a Galileo knelt before the cardinals and read a confession that the heliocentric theory was false.confession that the heliocentric theory was false.

Galileo was Galileo was never again a never again a free man, free man, living under living under house arrest house arrest and dying in and dying in 1642 in 1642 in Florence.Florence.

His books and His books and ideas still ideas still spread spread throughout throughout Europe.Europe.

SIR ISAAC NEWTONSIR ISAAC NEWTON

4. Isaac Newton4. Isaac Newton

1687- published 1687- published bookbook

English English

PhysicistPhysicist

Developed the law Developed the law of gravity & laws of of gravity & laws of motionmotion

What does an apple have to do What does an apple have to do with gravity? Ac-cording to with gravity? Ac-cording to George Stukeley, Newton’s George Stukeley, Newton’s biographer and friend, biographer and friend, Newton was sitting in the Newton was sitting in the shade of an apple tree when shade of an apple tree when an apple fell nearby. Newton an apple fell nearby. Newton began to wonder why apples began to wonder why apples always fall to the ground. always fall to the ground. Why don’t they fall sideways Why don’t they fall sideways or up? Newton reasoned that or up? Newton reasoned that the earth must have a power the earth must have a power that draws objects to it. That that draws objects to it. That was the beginning of the law was the beginning of the law of gravity.of gravity.

Newton established the Newton established the law of universal law of universal gravitationgravitation..

According to this law, According to this law, every object in the every object in the universe attracts every universe attracts every other object.other object.

In 1687, Newton wrote In 1687, Newton wrote Mathematical Mathematical Principles of Natural Principles of Natural PhilosophyPhilosophy, full of his , full of his ideas.ideas.

UNIVERSAL LAW OF GRAVITATIONUNIVERSAL LAW OF GRAVITATIONNEWTONIAN SYNTHESIS-RATIONAL PROOF FOR THE NEWTONIAN SYNTHESIS-RATIONAL PROOF FOR THE

HELIOCENTRIC MODELHELIOCENTRIC MODEL

NEWTON’S LAW OF GRAVITYNEWTON’S LAW OF GRAVITY

RENE’ DESCARTESRENE’ DESCARTES “I think, therefore, I am.” “I think, therefore, I am.”

Rene’ Descartes 1596-1650Rene’ Descartes 1596-1650

French mathematician French mathematician Invented analytical geometryInvented analytical geometryDeveloped a scientific method based on Developed a scientific method based on

rational rational deductiondeduction rather than empirical rather than empirical inductioninductionStressed rational speculation and reflectionStressed rational speculation and reflection

Descartes believed that he could rationally Descartes believed that he could rationally prove the existence of Godprove the existence of God

10. Rene Descartes10. Rene Descartes

1600’s1600’s

FrenchFrench

ScientistScientist

Supported idea Supported idea that human that human reason should be reason should be used to find truthused to find truth

A French researcher, A French researcher, Rene Rene DescartesDescartes relied on mathematics relied on mathematics and logic.and logic.

He believed that everything should He believed that everything should be doubted until proved by reason.be doubted until proved by reason.

“I think therefore I am.”

~Rene DescartesRene Descartes