Week 4: Isaac Newton
Notes on Stranges Chapter 5: “Scientific Revolution of the Sixteenth and Seventeenth Centuries 1600-1700”
The Scientific Revolution of the 16th and 17th centuries saw a shift in the center of science from Italy to northwest Europe, specifically England, France, and Germany.
Mechanical philosophy, the study of matter in motion, dominated scientific thinking during this period. Scientists aimed to discover and quantify laws of motion using mathematical equations, applicable from atoms to planets.
Key developments included increased experimentation and the invention of new instruments such as the telescope, microscope, barometer, vacuum pump, and thermometer.
Mathematical advancements like logarithms, analytical geometry, and calculus were also crucial.
The number of scientists increased, leading to the formation of scientific societies like England's Royal Society and France's Academy of Sciences, along with the publication of scientific journals.
Significant progress was made in astronomy and physics, with figures like Galileo Galilei, Johannes Kepler, and Isaac Newton discovering laws of motion and culminating in Newton's law of universal gravitation.
Newton's particle theory of light became dominant, and he demonstrated that white light is composed of seven colors. Astronomers also calculated the speed of light.
The speed of sound was measured, and it was determined that sound waves need a medium for transfer, unlike light.
Investigations into the nature of a vacuum led to the invention of the barometer.
Studies of gases began, and Boyle's Law describing the inverse relationship between pressure and volume of a gas was established.
William Harvey discovered the circulation of blood, complementing Vesalius's work on human anatomy.
The scientific method and empirical science were promoted using new instruments, with advances in mathematics allowing for more complex calculations and expression of results.
The influence of those in industry and commerce grew, leading to industrial pollution, as seen in England with the use of coal.
The particle theory of light was widely accepted, with Newton as its primary advocate, based on the observation that light travels in straight lines and casts sharp shadows. Newton incorrectly believed light travels faster in denser mediums.
Newton built the first reflecting telescope, using a concave mirror, to eliminate chromatic aberration.
Newton's prism experiment showed white light consists of seven colors and that the prism separates, but does not create the colors.
The wave theory of light had few proponents, such as Grimaldi, who demonstrated diffraction, the bending of light around an opening or edge, and Huygens who proposed that light consisted of longitudinal waves.
Scientific societies grew, with the Royal Society of London and the Académie Royale des Sciences in Paris being among the most influential.
Newton's life was marked by political and social upheaval, including the English Civil War and the London plague.
Newton made significant contributions to mathematics and physics, including the invention of calculus.
Leibniz independently invented calculus, and a controversy arose between him and Newton over priority of invention.
Astronomers focused on the attractive force exerted by the Sun on planets. Newton theorized that planets move naturally in straight lines, and that an inward attractive force pulls them from this path.
Newton used the idea that the Moon is a falling body and that the same force attracts the Moon and objects falling on Earth. He suspected the attractive force decreased according to an inverse square law.
Hooke calculated the centripetal acceleration for a body moving uniformly around a circle.
Newton's laws of motion and universal gravitation were published in his
in 1687.
Newton's first law of motion describes inertia; the second law, F=ma; and the third law, that every action has an equal and opposite reaction.
Newton derived the inverse square law of universal gravitation, expressing the force between two bodies, which involved calculating the gravitational constant G.
Leibniz and other European physicists initially rejected Newton’s concept of gravity because it implied action at a distance.
Emile du Châtelet's French translation of the Principia made Newtonian ideas available in France.
Henry Cavendish provided the first accurate measurement of Earth’s mass, using a torsion balance and Hooke’s law.
Cavendish used the torsion balance to measure the gravitational force between spheres, enabling the first precise calculation of G.
Newton's mechanical universe completed the scientific revolution, marked by new instruments, mathematical developments, and a new view of nature as matter in motion.
Instruments and quantitative measurements were essential for the mechanical philosophy.
The study of matter in motion was foundational for many scientific advancements during the era including chemistry, the speed of light, Newton’s theory of light, the barometer, blood circulation, and universal gravitation.
Notes on Isaac Newton by Gale Christianson
The circumstances of Newton’s birth involved a widowed mother before Newton was born, and both of Newton’s parents were illiterate
Science was Newton’s passion from a young age
Newton brought together his physics and Copernicus’ astronomy