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During the 1500s and 1600s, a handful of brilliant individuals laid the foundations for science as we know it today. Some historians consider the development of modern science the most important event in the intellectual history of humankind.

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The series of events that led to the birth of modern science is called the Scientific Revolution. It occurred between about 1540 and 1700. Why would the birth of science be called a “revolution”? The answer is that science was a radical new idea. It was a completely different way of looking at the world.

Before the Scientific Revolution, most educated people who studied the world took guidance from the explanations given by authorities like ancient Greek writers and Catholic Church officials. After the Scientific Revolution, educated people placed more importance on what they observed and less on what they were told. They gained knowledge by observing the world around them and coming up with logical explanations for what they saw.

Understanding Science

Science is a particular way of gaining knowledge about the world. In fact, the word science comes from a Latin word meaning “knowledge” or “understanding.” Science starts with observation. Scientists observe, or look at, the world. By observing the world they can identify facts about it. A famous scientist once said, “Science is built up with facts, as a house is with stones. But a collection of facts is no more a science than a pile of stones is a house.”

So scientists do more than identify facts. They use logic to explain the facts they have observed. The explanations scientists develop based on these facts are called theories. Theories are not accepted on faith. They must be tested to see if they are true. Scientists design experiments to test their theories. If the experiments keep showing that the theory makes sense, the theory is kept. If the experiments do not support the theory, scientists try a new theory. In this way, scientists learn more about the world.

As you can see, scientific knowledge is based on observations, facts, and logical ideas, or theories, about them. Before the Scientific Revolution, this method of gaining knowledge was uncommon.

Roots of the Revolution

Some of the main ideas of science had been expressed long before the Scientific Revolution. In fact, some of the basic ideas of science are ancient.

Greek Thinkers

Many Greek thinkers expressed ideas that, today, we would call scientific. The great philosopher Aristotle, for example, wrote about astronomy, geography, and many other fields. But his greatest contribution to science was the idea that people should observe the world carefully and draw logical conclusions about what they see. The use of observation and logic, as you have just read, is important in gaining scientific knowledge.

Another Greek thinker was Ptolemy (TAHL-uh-mee), an ancient astronomer. He studied the skies, recorded his observations, and offered theories to explain what he saw. Ptolemy was also a geographer who made the best maps of his time. His maps were based on observations of the real world. Aristotle, Ptolemy, and other Greek thinkers were rationalists, people who looked at the world in a rational, or reasonable and logical, way. During the Renaissance, Europeans studied the works of Greek rationalists. As a result, they began to view the world in a rational way. They began to think like scientists.


Preserving Ancient Knowledge

European scholars could study ancient Greek writings because of the work of others. Muslim scholars translated Greek writings into Arabic. They studied them for centuries and added their own new ideas. Later, the Arabic versions were translated into Latin, which was read in Europe. This work preserved ancient knowledge and spread interest in science to Europe.

Other religious scholars also played a role in preserving Greek ideas. The Jewish scholar Maimonides (my-MAHN-uh-deez) studied and wrote about Aristotle, trying to unite his work with Jewish ideas. The Christian scholar Thomas Aquinas tried to unite the work of Aristotle with Christian ideas. Other Christian scholars studied Greek ideas in Europe’s universities.

Developments in Europe

The Scientific Revolution was not just the result of European scholars studying ancient Greek writings. Developments in Europe also helped bring about the Scientific Revolution. One development that helped lead to the Scientific Revolution was the growth of humanism during the Renaissance. Humanist artists and writers spent much of their time studying the natural world. This interest in the natural world carried forward into the Scientific Revolution.

Another development was a growing interest in alchemy (AL-kuh-mee). Alchemy was a forerunner of chemistry. Alchemists experimented with various natural substances. They were best known for trying to change other metals into gold. Although they failed at that, alchemists succeeded in using experiments to learn more about how nature worked.

All of these developments—the interest in ancient Greek writings, the growth of humanism, the experiments of alchemists—came together in the early 1500s to bring about the Scientific Revolution.


During the Renaissance, European scholars eagerly read and studied the works of Greek rationalists. Aristotle, Ptolemy, and others were viewed as authorities.

Then an event took place that caused Europeans to doubt some of what the Greeks had said. In 1492, Christopher Columbus sailed west across the Atlantic Ocean in hopes of reaching Asia. As a guide, he took the map of the world that Ptolemy had created. Columbus never reached Asia because he ran into North America instead. Within a few years voyages of exploration made it clear that there was an entire continent that Europeans hadn’t even known existed.

This discovery stunned Europeans. This continent was not on Ptolemy’s map. Ptolemy was wrong. Observation of the real world had disproved the teachings of an ancient authority. Soon, European scholars began to question the accuracy of other Greek authorities. More and more, observations the Europeans made did not fit with what the authorities had described. Such observations helped lead to the Scientific Revolution.


In 1543 an astronomer published a book that contradicted what a Greek authority had written. Many historians think the publication of this book marks the beginning of the Scientific Revolution.

Nicolaus Copernicus

The book thought to have marked the beginning of the Scientific Revolution was written by a Polish astronomer, Nicolaus Copernicus (kuh-PUHR-ni-kuhs). His 1543 book was called On the Revolution of the Celestial Spheres. Copernicus was familiar with Ptolemy’s theories and writings. Ptolemy had written that the earth was the center of the universe and that the sun and other planets orbited, or circled around, the earth. For 1,400 years, people accepted this belief as fact.

As Copernicus studied the movements of the planets, however, what Ptolemy stated made less and less sense to him. If the planets were indeed orbiting the earth, they would have to be moving in very complex patterns. So Copernicus tried a different explanation for what he observed in the sky. Copernicus asked, What if the planets actually orbited the sun? Suddenly, complex patterns weren’t necessary to make sense of what Copernicus observed. Instead, simple circular orbits would account for the planets’ movements.

What Copernicus had done was practice science. Instead of trying to make his observations fit an old idea, he came up with a different idea—a different theory—to explain what he observed. Copernicus never proved his theory, but the Scientific Revolution had begun.


Brahe and Kepler

Another important astronomer of the Scientific Revolution was Tycho Brahe (TYOO-koh BRAH-huh). Brahe, who was Danish, spent most of his life observing the stars. In the late 1500s, he charted the positions of more than 750 of them.

What Brahe did, however, was less important than how he did it. Brahe emphasized the importance of careful observation and detailed, accurate records. Careful recording of information is necessary so that other scientists can use what has previously been learned. In this way, Brahe made an important contribution to modern science.

Brahe was assisted by the German astronomer Johannes Kepler. Later, Kepler tried to map the orbits of the planets. But Kepler ran into a problem. According to his observations, the planet Mars did not move in a circle as he expected it to. Kepler knew that Copernicus had stated that the orbits of the planets were circular. But Kepler’s observations showed that Copernicus was mistaken. In 1609 Kepler wrote that Mars—and all other planets—moved in elliptical, or oval, orbits instead of circular ones. Here was a new theory that fit the observed facts.

Kepler’s work helped prove Copernicus’s theory that the planets orbit the sun. In fact, Kepler became one of the first scientists to speak out in support of Copernicus.
Kepler continued to study the planets for the rest of his life. His basic ideas about the planets’ movements are still accepted by scientists today.



Galileo Galilei (gal-uh-LEE-oh gal-uh-LAY) was one of the most important scientists of the Scientific Revolution. He was the first person to study the sky with a telescope. With his telescope, Galileo discovered craters and mountains on the moon. He also discovered that moons orbit Jupiter.

Galileo was interested in more than astronomy, however. He also was interested in such things as how falling objects behave. Today, we use the term mechanics for the study of objects and motion.

Galileo’s biggest contribution to the development of science was the way he learned about mechanics. Instead of just observing things in nature, he set up experiments to test what he observed. Galileo was the first scientist to routinely use experiments to test his theories. For this, he is remembered as the father of experimental science.



The high point of the Scientific Revolution was marked by the publication of a remarkable book. This book, published in 1687, was Principia Mathematica. Its author was the English scientist Sir Isaac Newton. Newton was one of the greatest and most influential scientists who ever lived. Newton studied and simplified the work of earlier scientists. In doing so, he:

  • reviewed everything scientists had been learning,
  • coupled it with his own observations and ideas, and
  • identified four theories that described how the physical world worked.

Some of his theories have been proven so many times that they are no longer called theories, but laws.

One of Newton’s laws is called the law of gravity. You may know that gravity is the force that attracts objects to each other. It’s the force that makes a dropped apple fall to the ground and that keeps the planets in orbit around the sun.

Newton’s other three laws are called the laws of motion. They describe how objects move in space. You may have heard of one of them: “For every action there is an equal and opposite reaction.” Newton proposed that the universe was like a huge machine. Within this machine, all objects follow the laws he identified. In short, Newton explained how the physical world worked—and he was correct. Newton’s laws became the foundation of nearly all scientific study until the 1900s.

Newton also invented calculus, an advanced form of mathematics that scientists use to solve complex problems. For this, and for his laws of motion, Newton is remembered as a great scientist.



During the Scientific Revolution, scientists invented new and better instruments. These helped them study the natural world.

Around 1590, a Dutch lens maker named Zacharias Janssen invented a simple microscope. The first person to use a microscope as a scientific instrument, though, was the Dutch scientist Antoni van Leeuwenhoek (LAY-ven-hook) in the mid-1600s. Examining a drop of pond water with his microscope, he saw tiny plants and animals not visible to the naked eye.

In 1593, Galileo invented the thermometer. Thermometers are used to measure temperature. About 50 years later an Italian doctor developed a more accurate model than Galileo’s.

The telescope was probably invented by a Dutch lens maker in 1608. The next year, Galileo built a much-improved telescope that he used to make his important astronomical discoveries.

In 1643, the Italian scientist Evange-lista Torricelli invented the barometer. A barometer is a scientific instrument that measures air pressure. Barometers are used to help forecast the weather.

These instruments—the microscope, the thermometer, the telescope, and the barometer—are very common today. In fact, you have probably used at least one of them yourself. But when they were invented, they were dramatic advances in technology. They gave scientists the tools they needed to make more accurate observations of the world and to conduct experiments. They were the tools of the Scientific Revolution.


Today scientists use a procedure called the scientific method when doing their research. The scientific method is a step-by-step method for performing experiments and other scientific research.

The scientific method combines Bacon’s idea of a systematic scientific process, Descartes’s insistence on proof and clear reasoning, and the work of other scientists. Using the scientific method, scientists have learned more about the universe in the few hundred years since the Scientific Revolution than in all of the thousands of years that came before. Because of this, the basics of the scientific method—observation and experimentation—are considered the main principles of modern science.

There are six basic steps in the scientific method:Scientific_Revolution_-_Scientific_Method.gif

1. Stating the problem. The problem is often a question that begins with why. For example, Copernicus’s problem today would be stated, “Why do the planets move as they do?”

2. Gathering information. This can involve reading what other scientists have written and making observations.

3. Forming a hypothesis. A hypothesis is a solution that the scientist proposes to solve the problem. A hypothesis differs from a theory in that a hypothesis has not yet been tested.

4. Testing the hypothesis by performing experiments.

5. Recording and analyzing data gathered from the experiments.

6. Drawing conclusions from the data collected.

After scientists have concluded their experiments, they typically publish their results. This sharing of ideas is very important for two reasons. First, publishing results lets other scientiststry to reproduce the experiments. By reproducing experiments, scientists can determine whether the results are the same. If they are, they can be reasonably sure that the results are accurate. Second, publishing results spreads scientific knowledge. New scientific knowledge builds on previous knowledge. Sir Isaac Newton once wrote, “If I have seen further it is by standing on the shoulders of Giants.”


Some of the most important effects of the Scientific Revolution had nothing to do with science at all. When philosophers began applying scientific thought to other areas of human life, they came up with some startling new ideas.

The Power of Reason

By the end of the Scientific Revolution, one thing had become clear to many European thinkers: human reason, or logical thought, was a powerful tool. After all, scientists using reason had made many discoveries about the universe in a relatively short time. Since reason had proven itself as a way to learn some of nature’s great secrets, might reason also be used to solve the problems facing people? Philosophers decided to use reason when they considered society’s problems like poverty and war, or what type of government is best. This use of reason to consider the problems of society led philosophers to look at the world in a new way. They thought they could use reason to determine how to improve society.

Democratic Ideas

One way in which scientists thought they could improve society was by changing its government. Scientists’ use of reason and logic during the Scientific Revolution helped pave the way for the beginnings of democratic thought in Europe. As scientists like Sir Isaac Newton studied the world, they discovered laws that governed nature. In time, some scientists began to think that there must be laws that governed human behavior as well. Once people learned what these laws were, the scientists argued, they could improve their lives and their societies. But the idea that people’s lives were governed by laws had a deeper meaning as well. If all people were governed by the same laws, then it stood to reason that all people must be equal. This idea of the equality of all people was a fundamental step in the development of democratic ideas in Europe.



The Roman Catholic Church was a powerful force in Europe during the time of the Scientific Revolution. The birth and growth of science led to conflicts between scientists and the Church.

Reason for Conflict

There were two related parts to the conflict between science and the Church. The first was that the new science was putting forth ideas that contradicted Church teachings. For example, Copernicus’s idea that the earth orbited the sun contradicted the Church teaching that the earth was at the center of the universe.

A second part of the conflict was related to the first. When people contradicted the Church’s teachings, they weakened the Church. Church officials were afraid that questioning even one Church teaching might lead to more and more questions about the Church. People might even start to doubt key elements of the faith. Church officials feared this would undermine the Church’s influence.

The Trial of Galileo

The conflict between science and the Church was illustrated by a trial. Galileo published a book that supported the view that the planets orbit the sun. For this, he was put on trial by the Inquisition, a Church court that investigated people who questioned Church authority. Catholic officials insisted that Galileo publicly reject his findings and accept Catholic teachings that the earth was the center of the universe and did not move. Under threat of torture, Galileo agreed. Still, legend has it that as Galileo left his trial, he muttered, “And yet it does move.” Although he is remembered for opposing this Church teaching, Galileo was a devout Catholic. He believed that experimentation was a search for an understanding of God’s creation.


Knowledge and Belief

Many of the scientists you have been reading about held views similar to Galileo’s. For the scientists of the Scientific Revolution, science and traditional religious beliefs could exist at the same time. Nicolaus Copernicus served as a Church official. Sir Isaac Newton saw a close connection between science and religion. For example, Newton believed that all forces in nature were actions directed by God.

Despite the conflicts, science developed rapidly after the Scientific Revolution. Scientists made—and continue to make—countless discoveries. Scientific knowledge has changed human life dramatically and touches your life every day. Therefore, the Scientific Revolution ranks as one of the most influential events in history.