The Scientific Revolution

While the Renaissance and Reformation were taking place, another revolution in European thought was also occurring. It

changed how people viewed their place in the universe.

The Roots of Modern Science

The Medieval View• Before 1500, scholars

generally decided what was true or false by referring to an ancient Greek scholar or to the Bible.

• Whatever Aristotle said about the material world was true unless the Bible said otherwise.

• Few questioned the scientific ideas by carefully observing nature for themselves.

The Medieval View• Most scholars believed that the

earth was an unmoving object located at the center of the universe, known as the geocentric theory.

• Common sense seemed to support this view. After all, the sun appeared to be moving around the earth as it rose and set.

• It was also supported by Aristotle and Christianity.

A New Way of Thinking• Beginning in the mid-1500s, a

few scholars challenged the ideas of the ancient thinkers and the church, known to historians as the Scientific Revolution.

• The Scientific Revolution was a new way of thinking about the natural world based upon careful observation and a willingness to question accepted beliefs.

A New Way of Thinking• A combination of discoveries and circumstances led to

the Scientific Revolution and helped spread its impact:• 1)European scholars translated many ancient and current

scientific works by Muslims scholars.• 2)Uncovering many ancient manuscripts showed that the

ancient authorities often did not agree with each other.• 3)European explorers traveling to Africa, Asia, and the

Americas were inhabited by peoples and animals previously unknown. These discoveries opened Europeans to the possibility that there were new truths to be found.

A New Way of Thinking• 4) Exploration also fueled scientific research,

especially in astronomy and mathematics. Navigators needed better instruments and geographical measurements to determine their location in the open sea.

• 5) The invention of the printing press helped spread challenging ideas.

• As scientists began to look more closely at the world around them, they made observations that did not match the ancient beliefs.

A Revolutionary Model of the Universe

The first major challenge to science came in the field of astronomy. The Scientific Revolution began when a

small group of scholars began to question the geocentric theory.

The Heliocentric Theory• The geocentric theory troubled a

Polish astronomer named Nicolaus Copernicus in the early 1500s.

• After studying planetary movements for more than 25 years, Nicolaus Copernicus reasoned that the stars, earth, and other planets revolved around the sun.

• This is called the heliocentric theory.

The Heliocentric Theory• Copernicus’s theory still

did not completely explain the planets’ orbits. He thought they orbited in a perfect circle.

• Knowing most scholars and clergy did not publish his findings until 1543, the last year of his life.

Galileo’s Discoveries• In 1581, a 17-year-old

Italian student named Galileo Galilei discovered the law of the pendulum which states that each swing of a pendulum takes exactly the same amount of time.

• This disproved Aristotle, who said it swings at a slower rhythm as it approaches its resting place.

Galileo’s Discoveries• In another study, Galileo found

that a falling object accelerates at a fixed and predictable rate.

• Aristotle said that heavy objects fall faster than lighter ones.

• According to legend, he dropped stones of different weight from the Leaning Tower of Pisa.

• Contrary to Aristotle, the objects fell at the same speed.

Galileo’s Discoveries• Without ever seeing one,

Galileo successfully built his own telescope.

• Galileo began to make observations which supported the theories of Copernicus.

• This frightened Christian leaders because it went against church teachings.

Galileo’s Discoveries

• If people believed the church could be wrong about this, they could question other church teachings, as well.

• In 1616, the Catholic Church warned Galileo no to defend the ideas of Copernicus.

• In 1632, he published a book supporting Copernicus’ theories.

Galileo’s Discoveries• Galileo was called to

Rome to stand trial in 1633.

• Under the threat of torture, he read a signed confession stating the ideas of Copernicus were false.

• He lived under house arrest until his death in 1642.

The Scientific Method

The revolution in scientific thinking developed into a new approach to

science called the scientific method.

The Scientific Method

• The scientific method is a logical procedure for gathering and testing ideas.

• It begins with a problem or question arising from an observation.

• Scientists next form a hypothesis, or unproved assumption.

• The hypothesis is then tested.• Scientists then interpret the data.• Finally, the conclusion either confirms or disproves the

hypothesis.

The Scientific Method

• The scientific method did not develop overnight.

• The work of two important thinkers of the 1600s, Francis Bacon and Rene Descartes, helped to advance the new approach.

The Scientific Method• Francis Bacon, an

English politician and writer, felt scientists should observe the world and gather information about it first.

• Then they should draw conclusions from that information.

The Scientific Method

• In France, Rene Descartes developed analytical geometry, which linked algebra and geometry.

• He believed everything should be doubted until supported by reason.

The Scientific Method• The only thing he knew

for certain was that he existed because he wrote, “I think, therefore I am.”

• From this starting point, he followed a train of strict reasoning to arrive at other basic truths.

The Scientific Method• Scientists have shown

that observation and experimentation, together with general laws that can be expressed mathematically, can lead people to a better understanding of the natural world.

Newton Explains the Law of Gravity

By the mid-1600s, the accomplishments of Copernicus and Galileo had shattered the old

views of astronomy and physics. Later, a great English scientist Isaac Newton helped to bring

together their breakthroughs under a single theory of motion.

Isaac Newton• Isaac Newton’s great

discovery was that the same force ruled the motions of the planets, the pendulum, and all matter on earth and in space.

• This was the law of universal gravitation, which states every object in the universe attracts every other object.

Isaac Newton• What does an apple have to do with

gravity?• 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 the fall sideways or up? Newton reasoned that the earth must have a power that draws objects to it. This was the beginning of the law of gravity.

Isaac Newton• In his book, Mathematical

Principles of Natural Philosophy, he describe the universe like a giant clock.

• Its parts all worked together perfectly in ways that could be expressed mathematically.

• Newton believed that God was the creator of this orderly universe, the clockmaster who had set everything in motion.

Isaac Newton

The Scientific Revolution Spreads

Careful observation and the use of scientific method eventually became important in many different fields.

Scientific Instruments

• The first microscope was invented by Zacharias Janssen in 1590.

• In the 1670s, Anton van Leeuwenhoek used the microscope to observe bacteria and red blood cells.

Scientific Instruments• In 1643, Evangelista

Torricelli developed the first barometer, a tool for measuring atmospheric pressure and predicting weather.

• In 1714, Gabriel Fahrenheit made the first thermometer to use mercury in a glass.

Medicine• Being able to control

disease is one of the most important developments of science.

• In the late 1700s, Edward Jenner introduced the first vaccine to prevent smallpox.

Discoveries in Chemistry• Robert Boyle pioneered

the use of scientific method in chemistry.

• Boyle’s Law explains how the volume, temperature, and pressure of gas affect each other.

• In 1774, Joseph Priestly discovered the gas, oxygen.

The Enlightenment

• Other scholars and philosophers also applied a scientific approach to other areas of life.

• Believing themselves to be orderly, rational, and industrious, they thought of themselves as enlightened.

• They would become the leaders of a new intellectual and social movement called the Enlightenment.