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.

While Ptolemy was wrong, a positive consequence of his work was that it allowed stargazers and astrologers to track the planets with greater precision

This is commonly known as the GEOCENTRIC view where a motionless Earth is at the center of the universe while the moon, sun, planets, and stars revolve around the Earth.Ancient astronomers also believed the Earth was composed of “heavy” elements while the celestial bodies were composed of completely different substances and thus were weightless, allowing them to orbit the Earth.

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.

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.

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!

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 His famous work On the Revolutions of the Heavenly Spheres, held the of the Heavenly Spheres, held the sun to be the center of the solar sun to be the center of the solar system aka, the HELIOCENTRICsystem aka, the 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.”

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.

Tycho BraheTycho Brahe (1546-1601)(1546-1601)

A Danish nobleman who received A Danish nobleman who received money from the king of Denmark to money from the king of Denmark to build an advanced observatory where build an advanced observatory where he studied the stars and planets; he studied the stars and planets; collecting over twenty years of data.collecting over twenty years of data.

He had a very limited understanding of He had a very limited understanding of mathematics, but hypothesized a mathematics, but hypothesized a universe that was part Ptolemaic and universe that was part Ptolemaic and part Copernican part Copernican (figure to the left)(figure to the left)..

2. Johannes Kepler2. Johannes Kepler

Late 1500’sLate 1500’s

GermanGerman

Math and astronomyMath and astronomy

Calculated the orbits Calculated the orbits of the planets of the planets (elliptical)(elliptical)

Johannes KeplerJohannes Kepler (1571-1630)(1571-1630)

Brilliant young assistant of BraheBrilliant young assistant of Brahe Formulated THREE laws of planetary motion:Formulated THREE laws of planetary motion:

Orbits of the planets are ELIPTICAL rather than Orbits of the planets are ELIPTICAL rather than circularcircular

Planets do NOT move at a uniform speedPlanets do NOT move at a uniform speedin their orbitsin their orbits

The time a planet takes to make its orbitThe time a planet takes to make its orbitis precisely related to its distance from the sunis precisely related to its distance from the sun

Kepler’s contributions are HUGE; Kepler’s contributions are HUGE; he had mathematically proved the he had mathematically proved the relations of a sun-centered solarrelations of a sun-centered solarsystem, aka HELIOCENTRICsystem, aka HELIOCENTRIC

1609-16421609-1642

ItalianItalian

Scientist & Scientist & astronomerastronomer

Invented the Invented the telescopetelescope

3. Galileo Galilei3. Galileo Galilei

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.

Galileo Galileo (1564-1642)(1564-1642)

Using a telescope which he refined, he viewed the moon with all Using a telescope which he refined, he viewed the moon with all of it’s irregularities and stated that the moon is NOT a luminousof it’s irregularities and stated that the moon is NOT a luminousobject but is actually made of earth-like substances.object but is actually made of earth-like substances.

Galileo’s greatest achievement was the elaboration and consolidationGalileo’s greatest achievement was the elaboration and consolidationof the of the experimental methodexperimental method; rather than speculate about what ; rather than speculate about what might or should happen, he conducted controlledmight or should happen, he conducted controlledexperiments to find out what actually did happen.experiments to find out what actually did happen.

Using experiments, Galileo formulated the Using experiments, Galileo formulated the law of inertialaw of inertiastating that rest is NOT the natural state of objects.stating that rest is NOT the natural state of objects. Galileo in 1591, according to the story, dropped a 10-poundGalileo in 1591, according to the story, dropped a 10-pound

and a 1-pound weight simultaneously from the top of the and a 1-pound weight simultaneously from the top of the Leaning Tower of Pisa.Leaning Tower of Pisa.

Galileo showed that despite all previous speculation on theGalileo showed that despite all previous speculation on thesubject two bodies of different weights, when allowance wassubject two bodies of different weights, when allowance wasmade for differences in air resistance due to differences of made for differences in air resistance due to differences of size or shape, struck the ground at the same time.size or shape, struck the ground at the same time.

Galileo was put on trial and condemned by the Catholic Galileo was put on trial and condemned by the Catholic Church because his discoveries contradicted scripture. Church because his discoveries contradicted scripture.

He was finally absolved by Pope John Paul II in 1992.He was finally absolved by Pope John Paul II in 1992.

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.

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.

5. Robert Boyle5. Robert Boyle

1600’s1600’s

English English

ChemistChemist

Distinguished Distinguished elements and elements and compoundscompounds

Boyle defined the term Boyle defined the term elementelement in 1661 as " . . . in 1661 as " . . . certain primitive and simple, or perfectly unmingled certain primitive and simple, or perfectly unmingled bodies; which not being made of any other bodies, bodies; which not being made of any other bodies, or of one another, are the ingredients of which all or of one another, are the ingredients of which all those called perfectly mixt bodies are immediately those called perfectly mixt bodies are immediately compounded, and into which they are ultimately compounded, and into which they are ultimately resolved." resolved."

Although Boyle's chief scientific interest was Although Boyle's chief scientific interest was chemistry, he developed a brilliant series of chemistry, he developed a brilliant series of experiments in which he used an air pump to experiments in which he used an air pump to create a vacuum. He also developed what later create a vacuum. He also developed what later became known as "Boyle's law" that the volume of became known as "Boyle's law" that the volume of a gas varies inversely with pressure.a gas varies inversely with pressure.

7. Andreas Vesalius7. Andreas Vesalius

1500’s1500’s

ItalianItalian

PhysicianPhysician

He accurately He accurately detailed the human detailed the human bodybody

8. William Harvey8. William Harvey1600’s1600’sEnglishEnglishBiologistBiologistDeveloped theory Developed theory of blood circulation of blood circulation (the heart pumps (the heart pumps blood through the blood through the body)body)

This illustration depicts one of William Harvey's experiments in his On the Circulation of the Blood (1628). Venal valves had already been discovered, but here Harvey shows that venal blood flows only toward the heart. He ligatured an arm to make obvious the veins and their valves, then pressed blood away from the heart and showed that the vein would remain empty because blocked by the valve.

9. Francis Bacon9. Francis Bacon

1600’s 1600’s

FrenchFrench

ScientistScientist

Developed the Scientific MethodDeveloped the Scientific Method

Not that bacon!Not that bacon!An English writer, An English writer,

Francis BaconFrancis Bacon believed that by believed that by better understanding better understanding the world, scientists the world, scientists would improve would improve people’s lives.people’s lives.

He urged scientists to He urged scientists to experiment by experiment by observing the world observing the world and drawing and drawing conclusions.conclusions. This Bacon!This Bacon!

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