# Isaac Newton's Phenomenal Discoveries That Changed the World Forever

One of the greatest physicists and mathematicians of all time, Isaac Newton's discoveries and inventions widened the reaches of human thought and demonstrated the power of the scientific way of thinking. This article talks about his discoveries, that gave physics its theoretical foundation, granted powerful tools to mathematics and created a launch pad for future developments in science.

Omkar Phatak

Last Updated: Apr 26, 2018

**- Sir Isaac Newton**

*Natural Philosophy*in his time) a firm physical and mathematical foundation. Newton's three laws of motion set the foundation for modern classical mechanics. His discovery of the gravitational force gave man the ability to predict movements of celestial objects, while simultaneously validating Kepler's laws and the heliocentric Copernican model of the solar system. His co-discovery of calculus provided a potent mathematical tool, aiding the precise analytical treatment of the physical world. One of Isaac Newton's inventions is the reflecting telescope, which was his entry card into the premier Royal Society of London. Here's a quick tour of his most important discoveries.

Newton's Discoveries in Theoretical Physics

*Philosophiæ Naturalis Principia Mathematica*(Latin for

*Mathematical Principles of Natural Philosophy*).

**Newton's Magnum Opus - The Principia**

*Principia*by scientists), he synthesized what was known, into a logically whole and consistent theoretical framework, through his laws of motion and theory of gravitation. Creating the great generalizations which bind all the loose threads of clues into a coherent whole, is an art that has been mastered by only a few till date. Sir Isaac Newton was one of them.

**"Truth is ever to be found in the simplicity, and not in the multiplicity and confusion of things."**Here are his major contributions to theoretical physics.

The Laws of Motion

**Newton's second law of motion defines a 'Force'**

- Every object stays in its state of rest or uniform motion, unless disturbed by an external force. (
*Law of Inertia*) - The force acting on a body is defined as the rate of change of its linear momentum, with time. (
*Force Law*) - Every action has an equal and opposite reaction. (
*Action-Reaction Law*)

Discovery of the Law of Gravitation

**A falling apple supposedly made Newton think about the 'Gravity' of the situation!**

**"Every particle of matter attracts every other particle with a force along the straight line joining them and is directly proportional to their masses, while inversely proportional to the square of the distance between them."****The Law of Gravitation**

**Newton validated Kepler's laws and the heliocentric model of the solar system**

*action at a distance*. A gravitational force acts between two particles even though they are not in contact with each other. That is, it manifests as an action at a distance. This concept proved to be the undoing of Newton's theory later and which was overthrown by Einstein's theory of

*General Relativity*.

Even though now superseded by general relativity, Newton's idea of gravitation serves well in understanding the motion of planets and stars to incredible accuracy.

Discoveries in Optics

**Inquiry into the nature of light - Opticks**

*Opticks*. What the principia did for mechanics, this book did for the field of optics, fundamentally revolutionizing it. Here are some of his most important findings.

*white light to be composed of component color wavelengths*. He demonstrated this with the use of a prism which dispersed a beam of white light into wavelengths of different hues. It's the same effect which leads to the formation of rainbows in the sky. Through this finding, he overturned the prevalent notion since Aristotelian times which stated that light was inherently white and colorless.

*How do various colors arise?*'. His experiments revealed that color arose from reflection and transmission of light and primarily from

*selective absorption of light*by materials. From observation of the different angles at which individual wavelengths of light dispersed from a prism, he concluded that color arises from a fundamental property of light itself, though revealed only through interaction with matter.

**Newton showed white light to be made of component colors.**

Newton's Law of Cooling

Among his other stellar discoveries, Newton also came up with an empirical theory explaining the rate at which your hot cup of coffee cools. The law discovered by him states that the

where, T is temperature of the body, K is a constant, dT/dt is a time derivative representing change of temperature and T

*rate of cooling in a body is directly proportional to temperature difference between the body and its surroundings*. Mathematically, it can be stated as follows:**dT/dt = - K (T - T**

_{s})where, T is temperature of the body, K is a constant, dT/dt is a time derivative representing change of temperature and T

_{s}is the temperature of surroundings. (*The derivative is 'negative' as the body is cooling*).Newton's Discoveries in Mathematics

Binomial Theorem

Under the tutelage of Isaac Barrow at Cambridge, Newton's mathematical genius flowered. His first original contribution to mathematics was the advancement of binomial theorem. Through the usage of algebra of finite quantities in an infinite series, he included negative and fractional exponents in the binomial theorem.

Calculus

Isolated during the plague years (1665-1666) at Woolsthorpe Manor, Newton came up with his greatest breakthroughs in physics and mathematics. Through invention of Infinitesimal Calculus, (

*credit for which also belongs to Leibniz*), Newton provided a mathematical framework which enabled the study of*continuous changes*. He called it the*Science of Fluxions*. The invention of calculus ranks right up there with invention of fire or the building of the first steam engine. His approach to calculus was geometrical, in contrast to Leibniz, who was inclined more towards the analytical side.Newton-Raphson Method

He also made contributions to numerical analysis in the form of the Newton-Raphson method. In the book,

where x

*De analysi per aequationes numero terminorum infinitas*(Latin for*On analysis by infinite series*), published in 1771, Newton described this iterative method of approximation to calculate roots of real-valued functions. The method is described by the following formula.**x**

_{n+1}= x_{n}- f(x_{n}) / f^{'}(x_{n})where x

_{n+1}is the root calculated from the*n+1*^{th}iteration, x_{n}is approximate root from the previous iteration, f(x_{n}) is the function to be solved and f^{'}(x_{n}) is the derivative of the function.Newton's Inventions

Reflecting Telescope

During his investigation in optics, Newton also developed an alternative telescope design, which side-stepped some of the inherent flaws of the prevalent refraction-based design. What is now known as the Newtonian telescope is designed with a paraboloid mirror at the base which reflects the incoming light onto a slanted flat secondary mirror. This flat mirror ultimately reflects the collected light to an eyepiece for observation. Besides solving the problem of chromatic aberration - the bane of refracting telescopes, it is also comparatively cheaper to build.

**Newton's Reflecting Telescope**

Cat Doors

The invention of the pet door, now a common feature in many American or European homes is often attributed to Newton, who supposedly came up with the idea, to allow his pet cats to travel in and out without disturbing him. Though this claim stays unsubstantiated and the sources are largely anecdotal, it makes for an interesting addition to Newton's repertoire of inventions.

*why*and

*how*to begin the adventure which is pursuit of truth. This journey not only gives you proverbial intellectual high, but also connects you more deeply with nature. Those of you who enjoy this kind of a pursuit, may understand the way of thinking that led to some of the greatest of his discoveries. Remember, it all began with a 'Why?'. I leave you with a gem of a thought, from the man himself.

**"No great discovery was ever made without a bold guess." ― Isaac Newton**