The Scientific Revolution

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

In the Renaissance, people questioned how the universe worked. In the Renaissance, people questioned how the universe worked. This caused the Scientific Revolution.

The Aristotelian View of the Universe Aristotle put forth this view of the universe in the 4 th century B.C. Aristotle put forth this view of the universe in the 4 th century B.C. 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. 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. Notice also that it was believed that the orbits were circular. Notice also that it was believed that the orbits were circular. 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. 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.

The Copernican Hypothesis In the 16 th century, the Polish monk, mathematician, and astronomer Copernicus ( ) challenged the geocentric theory. In the 16 th century, the Polish monk, mathematician, and astronomer Copernicus ( ) challenged the geocentric theory. His famous work On the Revolutions of the Heavenly Spheres, held the sun to be the center of the solar system aka, the HELIOCENTRIC theory. His famous work On the Revolutions of the Heavenly Spheres, held the sun to be the center of the solar system aka, the HELIOCENTRIC theory. His ideas are attacked by religious authorities; Luther called him “the fool who wants to turn the whole art of astronomy upside down.” His ideas are attacked by religious authorities; Luther called him “the fool who wants to turn the whole art of astronomy upside down.”

1. Nicolaus Copernicus 1500’sPolishAstronomy Heliocentric theory – the earth and planets revolve around the sun!

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

Copernicus’ theory still didn’t explain why the planets orbited the way they did. Copernicus’ theory still didn’t explain why the planets orbited the way they did. Fearing ridicule or persecution, Copernicus did not publish his findings until 1543, the year he died. Fearing ridicule or persecution, Copernicus did not publish his findings until 1543, the year he died.

Model of our Solar System

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

Italian Scientist & astronomer Invented the telescope 3. Galileo Galilei

GALILEO OBSERVED JUPITER AND THE ROTATION OF ITS MOONS

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

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

The pope called Galileo to Rome to stand trial.

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

Galileo was never again a free man, living under house arrest and dying in 1642 in Florence. Galileo was never again a free man, living under house arrest and dying in 1642 in Florence. His books and ideas still spread throughout Europe. His books and ideas still spread throughout Europe.

SIR ISAAC NEWTON

4. Isaac Newton published book EnglishPhysicist Developed the law of gravity & laws of motion

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

Newton established the law of universal gravitation. According to this law, every object in the universe attracts every other object. In 1687, Newton wrote Mathematical Principles of Natural Philosophy, full of his ideas.

UNIVERSAL LAW OF GRAVITATION NEWTONIAN SYNTHESIS-RATIONAL PROOF FOR THE HELIOCENTRIC MODEL

NEWTON’S LAW OF GRAVITY

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

Rene’ Descartes French mathematician French mathematician Invented analytical geometry Invented analytical geometry Developed a scientific method based on rational deduction rather than empirical induction Developed a scientific method based on rational deduction rather than empirical induction Stressed rational speculation and reflection Stressed rational speculation and reflection Descartes believed that he could rationally prove the existence of God Descartes believed that he could rationally prove the existence of God

10. Rene Descartes 1600’sFrenchScientist Supported idea that human reason should be used to find truth

A French researcher, Rene Descartes relied on mathematics and logic. A French researcher, Rene Descartes relied on mathematics and logic. He believed that everything should be doubted until proved by reason. He believed that everything should be doubted until proved by reason.

“I think therefore I am.” Rene Descartes ~Rene Descartes