Johannes Kepler
Galileo Galilie
Isaac Newton
Nicholas Copernicus

Robert Boyle
Margaret Cavendish
René Descartes
Francis Bacon
Andreas Vesalius



01 - Background to the Revolution

Medieval scientists were known as “natural philosophers.” They did not make observations of the natural world. They relied on a few ancient philosophers, especially Aristotle, for their scientific knowledge. In the fifteenth and sixteenth centuries, natural philosophers began to give up their old views and develop new ones. Renaissance humanists had learned Greek and Latin. They were able to read works by Ptolemy, Archimedes, and Plato. These writings made it obvious that some ancient thinkers disagreed with Aristotle. At the same time, the invention of new instruments, such as the telescope and microscope, made new scientific discoveries possible. The printing press helped spread new ideas quickly and easily.

Mathematics played an important role in the scientific achievements of the sixteenth and seventeenth centuries. Nicholas Copernicus, Johannes Kepler, Galileo Galilei, and Isaac Newton were all great mathematicians who believed that the secrets of nature were written in the language of mathematics. After studying the ideas of the ancient mathematicians, they sometimes rejected these ideas. They developed new theories that became the foundation of the Scientific Revolution.

02 - Revolution in Astronomy

Discoveries in astronomy were an important part of the Scientific Revolution. These discoveries changed how Westerners viewed the universe. During the Middle Ages, philosophers had created a model of the universe known as the Ptolemaic system. Ptolemy was the greatest astronomer of antiquity. He lived during the second century A.D. It was from his ideas and those of Aristotle that philosophers had built the Ptolemaic system. This system is called geocentric because it places Earth at the center of the universe.
According to this system, the universe is a series of concentric spheres (spheres one inside the other). Earth is fixed, or motionless, at the center of these spheres. The rotation of these spheres makes the heavenly bodies rotate around Earth.

In 1543, Nicolas Copernicus published his famous book, On the Revolutions of the Heavenly Spheres. Copernicus believed in a heliocentric, or sun-centered, model of the universe. He believed that the Sun, not Earth, was at the center of the universe. The planets, including Earth, revolved around the Sun.

Another mathematician, Johannes Kepler, used detailed astronomical data to create laws of planetary motion. His observations confirmed that the Sun was at the center of the universe. He also discovered that the orbits of the planets around the Sun were not circular, as Copernicus had thought. Instead, the orbits were elliptical (egg-shaped).

Another mathematician, Galileo Galilei, was the first European to make regular observations of the heavens with a telescope. He discovered mountains on the Moon, four moons revolving around Jupiter, and sunspots. His observations indicated that heavenly bodies were not pure orbs of light, but were composed of material substance like Earth. After Galileo published his discoveries in The Starry Messenger in 1610, the Catholic Church ordered him to abandon the Copernican system. The new system threatened the Church’s view of the universe and seemed to contradict the Bible. In spite of the
Church’s position, by the 1630s and 1640s, most astronomers had come to accept the heliocentric model. However, the problem of explaining motion in the universe had not been solved.
Isaac Newton is considered the greatest genius of the Scientific Revolution. His major work, Mathematical Principles of Natural Philosophy, is also known as Principia (the first word of its Latin title). In the Principia, Newton defined the three laws of motion that govern both the planetary bodies and objects on Earth. The universal law of gravitation explains why the planetary bodies do not go off in straight lines but continue in elliptical orbits around the Sun. The law states that every object in the universe is attracted to every other object by a force called gravity. Newton’s laws created a new picture of the universe. It was now seen as a huge machine that worked according to natural laws.

03 - Breakthroughs in Medicine and Chemistry

A revolution in medicine also began in the sixteenth century. In 1543, Andreas Vesalius wrote On the Fabric of the Human Body. In this book, he discussed what he had found when dissecting human bodies. He presented a careful and accurate examination of human organs and the general structure of the human body. In 1628, William Harvey published On the Motion of the Heart and Blood. His work was based on close observations and experiments. Harvey showed that the heart was the beginning point for the circulation of blood in the body. He also proved that the same blood flowed in both veins and arteries and that it makes a complete circuit as it passes through the body. These observations disproved many of the theories of Galen, a second century Greek physician. His theories had dominated medicine in the Middle Ages.

The science of chemistry also arose in the seventeenth and eighteenth centuries. Robert Boyle was one of the first scientists to conduct controlled experiments. His work on the properties of gas led to Boyle’s Law. This law states that the volume of a gas varies with the pressure exerted on it. In the eighteenth century, Antoine Lavoisier invented a system of naming the chemical elements. He is considered by many to be the founder of modern chemistry.

04 - Women and the Origins of Modern Science

Women as well as men were involved in the Scientific Revolution. Margaret Cavendish was one of the most prominent female scientists of the seventeenth century. She wrote a number of works on scientific matters, including Observations Upon Experimental Philosophy. In her work, she was critical of the belief that humans, through science, were masters of nature. In Germany, many of the women who were involved in science were astronomers. The most famous of the female astronomers in Germany was Maria Winkelmann. She made some original contributions to astronomy, including the discovery of a comet. However, when Winkelmann applied for a position as an assistant astronomer at the Berlin Academy, she was denied the position because she was a woman, even though she was highly qualified. Women scientists often faced these kinds of obstacles because scientific work was considered to be men’s work.

05 - Descartes and Reason

The Scientific Revolution strongly influenced the Western view of man. This is especially evident in the work of the seventeenth-century French philosopher René Descartes. The starting point for Descartes was doubt. In his most famous work, Discourse on Method, Descartes decided to set aside everything that he had learned and to begin again. One fact seemed to him to be beyond doubt—his own existence. From his first principle - “I think, therefore I am” - Descartes used his reason to arrive at a second principle, the separation of mind and matter. He argued that because “the mind cannot be doubted but the body and material world can, the two must be radically different.” Descartes’s idea that mind and matter were completely separate allowed scientists to view matter as something that was totally detached from themselves and that could be investigated by reason. Descartes has been called the father of modern rationalism. This system of thought is based on the belief that reason is the chief source of knowledge.

06 - The Scientific Method

During the Scientific Revolution, the scientific method was created. The scientific method is a systematic procedure for collecting and analyzing evidence. The person who developed the scientific method was Francis Bacon. He believed that instead of relying on the ideas of ancient authorities, scientists should use inductive reasoning to learn about nature. Scientists should proceed from the particular to the general. Systematic observations and carefully organized experiments to test hypotheses (theories) would lead to general principles. Bacon also believed that science could give humans power over nature.

07 - Screencasts

#1 - Scientific Revolution Part 1

#2 - Scientific Revolution Part 2

#3 - Scientific Revolution Part 3


09 - Full Youtube Videos