AP World History: The Scientific Revolution

Period 4: 1450 - 1750

Did You Know? The word science comes from the latin root scientia, meaning knowledge.

I Science and astronomy in the Classical World

A) Aristotle’s View of the Universe (4th century BCE): 55 crystalline spheres, celestial objects attached to spheres, spheres rotated at different velocities, the Earth was at the center.

Aristotle’s Prime Mover

Earth is at the center

of the Universe

All motion in the

heavens is uniform circular motion

Celestial objects are made from

perfect material and

cannot change their properties (e.g., their

brightness).

Astronomy in the Classical World Continued…

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B) The Ptolemaic Universe : Ideas about uniform circular motion and epicycles were catalogued by Ptolemy in 150 CE in his book the Almagest. This view was officially endorsed by the medieval Church.

Astronomy in the Classical World Continued…

II Science in the Middle Ages

A) During the Muslim Golden Age, scientific experimentation was encouraged. They had universities, trained doctors, invented vaccines for smallpox, algebra, etc…B) In Medieval Western Europe, true science was rare. The exception were alchemists (they tried to change ordinary metals into gold), but they had to often hide their experiments from the Church, who discouraged scientific inquiry.

Science in the Middle Ages Continued…

B) In the Middle Ages, the Church officially endorsed Ptolemy’s Geocentric Model of the universe.

Philosopher-theologian Thomas Aquinas (1222-1274) rediscovered

Aristotle and blended his ideas with medieval theology.

7Medieval Representation of Ptolemaic Universe

STABILITY Earth was at center. Mankind

important in God’s plan

COMFORTIndividual could

locate God. Soul’s destination would be above or below.

REASSURANCEDivine power would

triumph over corruption and

decay of earthly things and lift the soul to an afterlife

in heaven

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Aristotle’s Prime Mover became the

God of Christian theology.

The outermost sphere became

the Christian heaven.

Earth at center represented the Christian God’s

concern for mankind.

III Influence of the Renaissance

A) The Renaissance (15th – 16th centuries) led to the Scientific Revolution.

1. Humanism encouraged individual achievement, and knowledge of Classical civilizations (Greek and Roman).

2. The printing press spread new knowledge3. People began to question the Catholic Church4. The Medici family built an astronomical observatory and financially sponsored Renaissance scientists including Galileo!

IV Copernicus vs. PtolemyA) 1453 Nicolaus Copernicus , an astronomer and mathematician, published On the Revolutions of the Heavenly Spheres. In it, he proposed the Heliocentric Model of the universe; that the sun is the center of the universe. The Heliocentric System offers a simple explanation for varying brightness and retrograde motion. However, like Ptolemy, he mistakenly believed that planetary orbits were perfect circles.

Copernicus vs. Ptolemy Continued…B) Tycho Brahe (1546 – 1601) observed the movements of stars

and planets every night for years, and recorded the data. His assistant, Johannes Kepler (1571 – 1630), used Brahe’s data to

prove that Copernicus’s Heliocentric model was correct.

Tycho Brahe

Johannes Kepler

Why do you think that Brahe and Kepler wanted to

gather more evidence? Wasn’t Copernicus’s

findings enough?

V Galileo (1564 – 1642)A) Galileo Galilei from Pisa was an astronomer, philosopher, and mathematician. He impressed the Medicis and was appointed Royal Professor of Mathematics and Philosophy under Grand Duke Ferdinand I.B) With the political and economic protection of his Medici sponsors, Galileo began to experiment more freely. By dropping balls of different weight from a height, Galileo proved that objects fall at the same rate of acceleration, many years prior to Newton’s laws of Gravity.C) In 1609 he invented a refracting telescope, which allowed him to magnify celestial objects up to 30x their size.D) He was the first to observe 4 moons of Jupiter, and mountains on our moon. This evidence without a doubt proved Copernicus was right.E) 1633 he was tried before the Inquisition for heresy. He was forced to recant and to live under house arrest. Galileo’s friend Giordano Bruno had proclaimed

the universe infinite, and was burned alive.

Jupiter and its 4 Largest Moons

Today scientists estimate that Jupiter has 60+ moons! Io (far left) is the most volcanic place in our galaxy. Europa (center left) has a surface made of water ice. It is possible

that a liquid ocean of water is under the ice… is there life there?

Primary Sources: Galileo1.“I do not feel obliged to believe that the same god who has endowed

us with sense, reason and intellect has intended us to forgo their use.” – Galileo Galilei

2. …The proposition that the Sun is the center of the world and does not move from its place is absurd and false philosophically and formally heretical, because it is expressly contrary to Holy Scripture. – Trial of Galileo, June 1633

“More than 350 years after the Roman Catholic Church condemned Galileo, Pope John Paul II is poised to rectify one of the Church's

most infamous wrongs -- the persecution of the Italian astronomer and physicist for proving the Earth moves around the Sun…”

NY Times Oct 31, 1992

V Isaac Newton (1642 -1727)A) Newton discovered the force of gravity is what keeps the planets in orbit around the sun.B) Newton is also credited with inventing calculus.“If I have seen further than others, it is by standing upon the shoulders of giants.” - Newton

Many historians believe that Gottfried Leibnitz actually invented calculus before

Newton, and that Newton stole the credit!Newton

Liebnitz

Newton’s Laws for Dummies!“Law of Universal Gravitation: Prior to Newton and Galileo, most people thought that the forces causing motions on Earth and the forces causing the stars and planets to move were different forces. Newton realized that the same forces and the same laws of physics apply everywhere in the universe. So, his law of gravity is called the law of universal gravitation.Force of Gravity: There is a gravitational force acting between any two objects in the universe. There is a gravitational force between you and Earth. There is also a gravitational force between you and the Sun, between you and all the other planets, and between you and the people sitting next to you. Why do we fall down towards Earth rather than towards the Sun, another planet, or the people next to us? The force of gravity between us and Earth is larger than the force from any of these other objects. The force of gravity between two objects depends on the masses of the two objects and the distance between the centers of the two objects.

Newton’s Laws for Dummies!Gravitational Force and Mass: The more the masses of the objects, the larger the gravitational force between them. We don't fall towards the people next to us because they are much less massive than Earth. But the Sun is more massive than Earth. Why don't we fall to the Sun? It is much farther away. As the distance between two objects gets larger, the gravitational force between them gets smaller.Gravitational Force and Distance: When you are standing on Earth with your toes buried in the dirt, it may seem like the distance between you and Earth is zero. But, the distance is measured between the centers of the two objects not the edges. So the distance between you and Earth is the distance from the center of the Earth to your belly button. As the distance between two objects gets larger, the gravitational force between them gets smaller. It never gets to zero; it just gets too small to matter. If you were suddenly suspended in space twice as far from the center of the Earth as you are now. the gravitational force would be one fourth as much as it is on Earth's surface. If you weigh 100 pounds, you would suddenly weigh 25 pounds. No matter how far you got from Earth, there would still be some, very small, gravitational force between you and Earth. Astronauts in space are weightless because they are falling around the Earth, not because there is no gravity in space. There is gravity everywhere..”

-Paul A. Heckert, 2008“Newton's ideas about the universe held sway until Einstein introduced the general theory of relativity. But for most of what we observe in our daily experience, Newton's laws remain perfectly valid today.” Nova.com

A Black Hole, Gravity at its Finest!

VI Other Discoveries from the Scientific Revolution

Scientist Discovery

Leeuwenhoek Perfected the microscope.

Was the first to see

microorganisms.

Robert Boyle The first recognized

modern chemist. He argued

for the scientific

method, and that all

matter consists of tiny

particles.

Priestly and

Levoisier

Discovered the existence

of oxygen.

VII Scientific MethodOver time, a step-by-step process of discovery developed that

became known as the scientific method.

VIII Philosophy and the Scientific Revolution

A) Francis Bacon:“In order to test potential truths, or hypotheses, Bacon devised a method whereby scientists set up experiments to manipulate nature, and attempt to prove their hypotheses wrong. For example, in order to test the idea that sickness came from external causes, Bacon argued that scientists should expose healthy people to outside influences such as coldness, wetness, or other sick people to discover if any of these external variables resulted in more people getting sick. Knowing that many different causes for sickness might be missed by humans who are unable or unwilling to perceive them, Bacon insisted that experiments must be consistently repeated before truth can be known: a scientist must show that patients exposed to a specific variable more frequently got sick again, and again, and again.” –Khan Academy

“Knowledge is power.”

VIII Philosophy and the Scientific RevolutionB) Rene Descartes: “I think, therefore I am.”In short, his method required (1) accepting as "truth" only clear, distinct ideas that could not be doubted, (2) breaking a problem down into parts, (3) deducing one conclusion from another, and (4) conducting a systematic synthesis of all things. Descartes based his entire philosophical approach to science on this deductive method of reasoning. – Tim Nordgren, 1998

HW Questions1. How was the Scientific Revolution related to the Renaissance and

Humanism?2. Was the heliocentric model of the universe revolutionary? Explain.3. What does Galileo mean by quote #1? Do you agree or disagree?

Explain.4. According to quote #2, why did the Church condemn Galileo?5. If you were Galileo, what would you have said in your defense?6. Explain the laws of Newton and their significance.7. What were the two greatest achievements of the Scientific

Revolution (in your opinion) and why?8. How did Bacon and Descartes help create the Scientific Method? 9. Is the Scientific Method necessary? Why or why not?10. Did the Scientific Revolution try to end all religion? Explain.