1656: Pendulum Clock

The pendulum clock was invented by Christiaan Huygens in 1656 and became the worlds most accurate time-keeping device until the early 20th century.  It was accurate up to a degree of about fifteen seconds per day.

The clock only works on a stead and level surface – and motion will disrupt the movement of the swinging pendulum.  Its power source is a weight that very gradually drops and is reset by winding it up.  A complicated series of gears takes the energy from the weight and applies it to the pendulum, which rocks a lever called the escapement that locks and unlocks a gear at a constant speed.  Since a pendulum swings at a constant speed regardless of the distance it swings in provides a very accurate source of timekeeping.

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Christiaan Huygens

Christiaan Huygens

Christiaan Huygens (1629 – 1695) played a primary role in the discovery into the nature of light, developed the tools of calculus, published the first book on probability theory, and invented the first pendulum clock.  These accomplishments and more made him an important figure in the early scientific revolution.

Huygens was born into a wealthy Dutch family, excelled early in mathematics which he studies later on in college.  His early work focused on mathematics but he quickly turned his attention to the telescope in hopes to better understand how they work.  He used improved telescopes to identify the rings of Saturn and discover its largest moon, Titan.

In 1666 Huygens became a founding member of the French Academy of Sciences, one of the oldest scientific organizations in the world.  However Huygens is best know by his work on the nature of light.  Through his observations and experiments with light he became a proponent of the wave theory of light which was rejected by Isaac Newton for his particle theory of light.  The wave nature of light was confirmed by a double slit experiment by Thomas Young in 1803 and today we accept that light acts both as a wave and a particle.


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Isaac Newton

Born on Christmas Day in 1642, the world was gifted Isaac Newton (1642 – 1727) who went on to become the greatest scientist of his era and one of the most influential persons of all time.  He made a number of revolutionary discoveries involving mass, inertia, motion, gravitation, and optics.  In the process of achieving some of those discoveries, he invented an entire new field of mathematics called calculus.  Indeed, to see further than Newton one would have to be standing on the shoulders of a giant.

Isaac Newton

Newton grew up in England in an nurturing family environment as his father died before his birth and his mother left him in the care of his grandmother shortly after.   This early childhood experience surly affected his emotional state in adulthood.  Newton attended Cambridge University in 1661 at the time that the Scientific Revolution was underway.  In 1665 an outbreak of plague forced the university to close forcing Newton to return home.  During the next 18 months Newton produced some of his scientific best works.

As prolific as Newton’s lifetime scientific achievements were, he squandered much of his time during the 1670s studying alchemy, the occult, and writing religious tracts.  He became and increasingly isolated individual with an abrasive personality.  It was only with the encouragement and financial backing of his friend Edmond Halley that he published his most famous work Principia in 1687 which laid out his laws of motion and universal gravitation.

Newton’s scientific achievements awarded him an enormous amount of fame, influence, status, and wealth.  He was made a Fellow of Trinity College in 1667, elected Lucasian Professor of Mathematics in 1669, elected a Fellow of the Royal Society in 1672, elected a Member of Parliment in 1689, became Warden of the Mint in 1696, Master of the Mint in 1698, elected President of the Royal Society in 1703, and Knighted by Queen Anne in 1705.

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1687: Principia

Issac Newton’s 1687 publication of Mathematical Principles of Natural Philosophy, more commonly known as Principia, may have been the most important and influential scientific piece of literature of all time.  It’s impact on scientists was enormous and almost immediately introduced a new paradigm in physics. 

Principia was important for its all-encompassing explanation of physics expressed in mathematical form.  Two major ideas were expressed in the book.  First, it stated Newton’s famous laws of motion which form the foundation of classical physics.  Second, it stated Newton’s law of universal gravitation by showing how his inverse square law was perfectly compatible with Kepler’s elliptical planetary orbits.  All of these laws were proven with rigorous mathematical and experimental evidence.

Newtonian mechanics, as his methods came to be called, were important due to its value in everyday life such as engineering, astronomy, industry, agriculture and many other areas.

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Rene Descartes

Renee Descartes

The French mathematician Rene Descartes (1596 – 1650) insightfully connected the bridge between geometry and algebra by developing analytic or Cartesian geometry. Aside from his mathematical works he was extremely influential in other area’s of science and philosophy.

Descartes was born in France to a bourgeois family, educated at a Jesuits college, and joined the army at the age of 22 where he met a man named Isaac Beekman who kindled his interest in science and left an indelible stamp of influence on his early adulthood.   After a move to the Netherlands Descartes formulated some of his most influential ideas.  While Descartes was working with curves he realized that the key to solving them was by using coordinates.  In 1637 in his appendix to his book Discourse on Methods titled La Geometrie, Descartes shows how a single equation can be used to explain every single point along a curve.   This work laid the foundation for the invention of calculus by Newton and Leibniz.

In addition to his mathematical contributions Descartes was also influential in philosophy and science.  He was one of the first to break away from the Aristotelian Scholastic mode of thought, which was extremely entrenched in intellectual institutions during his life.  He wrote speculations on a multitude of topics including the nature of the mind, mind-body dualism, God, the sensations and passions, and morality.

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1662: Boyle’s Law

The discovery of the relationship between gas volume and air pressure was published by Robert Boyle in 1662.  It states that air pressure is inversely proportional to the volume it occupies, for a fixed temperature in a closed system. 

The original hypothesis was given to Boyle by Richard Towneley and his assistant Henry Power a year earlier via letter, and publication followed after Boyle and Robert Hooke checked the hypothesis with their own experiments.  In 1676 Edme Mariotte also came to the same conclusion independently but in addition discovered that air volume changes with temperature.

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Robert Boyle

The scientific contributions of Robert Boyle (1627 – 1691) cover of a variety of subjects including physics, hydrostatics, and the earth sciences, however he is best known for his contributions to the field of chemistry.  Through his efforts, his work helped to break away the scientific world from alchemy and to usher in modern chemistry.

Robert Boyle

Born in Ireland to a wealthy family, Boyle attended a private boarding school at the age of eight, followed by a tour of the European continent with his French tutor that ended in Italy at the time when the great Galileo died.  This experience had a profound impact on Boyle and when he returned to England where he hooked up with other like-minded individuals to form the “invisible college” where they met, often at Gresham College, and  was to be the precursor of the Royal Society of London.

At the same time Boyle hired Robert Hooke as his assistant.  The two like-minded men collaborated on many discoveries including Boyle’s Law, which states that pressure and volume of gas have an inverse relationship at a fixed temperature.

The publication of The Sceptical Chymist in 1661 which is considered by many as the beginning of modern chemistry.  The book is composed as a dialogue and in it he rejects the ideas of Aristotelian elements of earth, fire, wind, and water and suggests the idea that matter consists of atoms in motion and that every phenomenon is the result of the collisions of these particles.

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1643: Discovery of the Vacuum

The existence of a vacuum, a space completely empty of matter, had been debated since at least the ancient Greek philosophers, and probably much longer.  In 1643 the Italian physicist Evangelista Torricelli showed that for all practical purposes a vacuum was indeed possible. 

Torricelli discovered the vacuum accidentally when he was conducting experiments that were designed to solve the problem of pumping water out of a deep well.  He tried to scale down the problem using mercury instead of water because liquid mercury is much more dense than water and he hoped to be able to observe the same phenomenon at a lower height.  He took a tube closed at one end and filled it with mercury.  He stuck the open end in a bowl of mercury and slowly raised the closed end, where eventually a gap appeared about the mercury.  The gap could not have been air because when he lowered the tube again the gap vanished immediately, quicker than air could have dissipated.

The discovery of the vacuum was eventually applied to advances in technology and its principle is used in heating and cooling systems, light bulbs, steam engines, cathode ray tubes, and more.

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1590s: The Microscope

Like many inventions, the exact date of the first microscope is disputed and confused, however credit is sometimes given to Zacharias Janssen and his father Hans Martenz for creating the first microscope as early as 1590, or possibly in 1595.  While people were experimenting with ways to make objects larger in earlier times, such as by using water to bend light and magnify objects or by using very simple lens, these probably do not meet the qualifications to what most would consider a microscope. 

Early microscopes came in a variety of forms ranging from single, powerful lens such as the type that Antony van Leeuwenhoek created and used, to simple compound microscopes such as those created and used by Zacharias Janssen, Galileo, and Robert Hooke.  Although these microscopes provided increased magnification, problems with the image quality – such as chromatic aberration – persisted due to the relative low quality of glass used combined with design flaws.

Today microscopes are available in an even greater variety of forms that include stereo microscopes that have two eyepieces and various types of electron microscopes that employ beams of electrons rather than light since the wavelength of electrons is up to 100,000 times shorter than that of light, allowing for much greater magnification.

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Antony Van Leeuvenhoek

Antony Van Leeuwenhoek

Important advances in microbiology were made by Antony van Leeuvenhoek (1632 – 1723), which include a substantial improvement on the microscope followed by the discovery of a variety of single celled organisms.

Antony Van Leeuvenhoek was for his time an unusual candidate to make breakthrough scientific discoveries.  He earned no university degrees and therefore had no formal scientific training, and he was not particularly wealthy.  His trade was that of a textile merchant that led him to develop improved lens in order to better observe thread quality.  He cultivated in himself a tremendous skill in lens making with some of his lens being able to magnify up to 300 times and possibly higher, which was a significantly higher level of magnification than the compound microscopes of his day that only magnified around 20x – 30x.  During his lifetime he may have made over 500 magnifying lenses.

He used these lenses, along with his terrific eyesight and observational skills, to observe the first bacteria.  Through a friend he communicated with the Royal Society through dozens of informal letters, and although the Society was originally skeptical of his claims they were later verified by Robert Hooke and others. This led to his election into the Royal Society in 1680 and bestowed on him a tremendous amount of fame.

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