10 of Isaac Newton's most famous and revolutionary inventions

When you think about Isaac Newton, you probably think of the apocryphal story about an apple falling on his head, giving him the idea for the theory of gravity. You might also think that he is one of the most influential physicists and scientists of all time. 

But before we get into that, let's take a quick look at this great man's life.

Isaac Newton led a very fruitful life

Born in 1642, Sir Isaac Newton was raised by his grandmother until age 12. His mother pulled him out of school at age 12 to have him manage the family estates. Newton found farming monotonous, and he was soon sent back to school.

He studied law at Trinity College, Cambridge, taking care of wealthier students' rooms to pay his bills. During his time at Cambridge, Newton wrote down his thoughts in a set of notes called "Quaestiones Quaedam Philosophicae."

The notes show that Newton had already found the main ideas behind calculus, a new way of quantifying and studying the rate of change of a quantity over time. Along with German mathematician Gottfried Leibniz, Newton would develop the techniques of differentiation and integration, which remain fundamental to mathematics and science today.

In 1665 Cambridge closed temporarily due to an outbreak of bubonic plague, and Newton returned home to Lincolnshire for two years. He continued his studies on his own, during which time he had his "brainstorm" regarding gravity and developed his three laws of motion. He described these years as "the prime of my age for invention."

Newton returned to Cambridge in 1667 and was awarded the distinction of scholar, reserved for the highest-performing students. In 1670, he was appointed to the prestigious Lucasian Chair of Mathematics, aged just 27. He served as a mathematics professor and in other capacities until 1699.

An interest in optics led Newton to correctly propose that white light is actually the combination of light of all the colors of the rainbow. Using this knowledge, he designed a reflecting telescope that used mirrors and glass lenses, allowing it to focus all the colors on a single point—giving a crisper, more accurate image.

Newton published his findings in 1687 in Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), commonly known as the Principia. Although few people could fully grasp the science in the Principia, it was widely acknowledged as a work of genius.

For various reasons, Newton decided to leave Cambridge n 1696 to take up a government position as Warden of the Royal Mint. In 1703 he was elected president of the Royal Society and was re-elected each year until his death. He was knighted in 1705 by Queen Anne, the first scientist to be knighted for his work.

Throughout his life, Newton was responsible for several essential ideas and theories. Many of these are foundational to modern science and our understanding of the greater universe around us.

The modern world would look very different if Isaac Newton had decided that farming would better use his time and mind.

Let's take a look at some of the most significant ones.

1. Newton's laws of motion are probably his greatest gift to us all

In 1687, Isaac Newton developed his three laws of motion after discovering and studying gravity. They are:

1. The law of inertia/motion: An object at rest remains at rest, and an object in motion remains at a constant speed and in a straight line unless acted on by an unbalanced force.

2. The law of momentum (F = ma): An object's acceleration depends on the object's mass and the amount of force applied.

3. The law of action and reaction: Whenever one object exerts a force on another object, the second object exerts an equal and opposite on the first.

These laws are the foundation of classical mechanics, one of physics's main branches. Mechanics studies how objects move or do not move when forces act upon them.

Without them, modern physics would probably never have existed.

2. Newton had plans for an "Orbital Cannon"

Isaac Newton liked to play with ideas around the concept of universal gravitation. In thought experiments about it, he described a mountain that would be so tall it poked into space.

He thought that if such a mountain existed, you could put a cannon on top of it to shoot things into space.

This was a way to explain how one object might orbit another. 

He theorized that if you gave the cannonball the perfect amount of gunpowder on the launch, you could give it enough velocity to fall towards Earth at the same rate the planet curved away from it. The cannonball would continue in free fall around the planet, orbiting it.

Pretty cool.

3. Newton also worked on an actual "Philosopher's Stone"

Isaac Newton was interested in mathematics and physics and worked in areas that strayed away from what we now consider more traditional science. Some were so "off-topic" by modern notions that they were more like alchemy or mystical ideas, like how to make the philosopher's stone. 

The "philosopher's stone" was a mythical substance that alchemists believed had magical properties, including being capable of bestowing the abilities of transmutation (including turning base metals into gold) and immortality. Theoretically, the stone could turn lead into gold or cure any disease.

It is important to remember that when Newton was alive, many still saw alchemy as legitimate science. 

Documents that have recently come to light give Newton's handwritten instructions for making "philosophic" mercury. The document's title translates, in part, to "Preparation of the [Sophick] Mercury for the [Philosophers'] Stone."

4. Calculus was an enormous intellectual feat

Isaac Newton and Gottfried Wilhelm Leibniz are said to have independently invented calculus at around the same time, although each claimed the other had stolen his work. Newton discovered that algebra and geometry weren't powerful enough for the science he was working on, so he developed a new means of mathematics to decode the world around him properly.

At its most basic, calculus is all about studying the rate of change of a quantity over time. In his work on gravity, Newton first tried to describe the speed of a falling object. When he did this, he found that the speed of a falling object increased every second but that there was no existing mathematical explanation for this. 

In mathematics up to that time, there hadn't been a lot of study of movement and the rate of change. 

Newton's theory of gravity also used planetary ellipses to explain how the planets move around the Sun. By using calculus, he could explain how planets move and why the orbits of planets are in an ellipse.  

One of his significant breakthroughs was finding that the gravitational force that holds us to the ground is the same force that causes the planets to orbit the Sun and the Moon to orbit Earth.

5. Newton made significant contributions to our understanding of the refraction of light

In 1704, Newton wrote a book on the refraction of light titled Opticks. It changed the way that scientists thought about light and color. 

Scientists in the early 18th century knew rainbows formed when the light was refracted through water (or a prism), but they had no idea why this produced so many colors. The standard theory was that the water "dyed" the Sun's rays or that color was created by mixing light and dark. 

Beginning in 1666, Newton conducted studies with a lamp and a prism. Newton set up a way to turn the 'rainbow' rays back into white light. This showed that white light is a mixture of different colored rays, which can be separated when light passes through a prism. His experiments also revealed that color arose primarily from materials' selective light absorption. 

This discovery hugely affected astronomy, as Newton used it to develop a more powerful telescope that could produce much clearer images.

6. He also advanced our understanding of cooling

Newton became particularly interested in the physics of how things cool. His research on this mainly focused on red-hot iron balls in different fluids. He noticed that the difference in temperature between the iron ball and the air surrounding it ended up being less than 50 degrees Fahrenheit, or roughly a difference of about 28 degrees Celsius.

He established a correlation between the rate of heat loss and the temperature difference between the ball and the fluid. 

Newton's Law of Cooling states that a body's heat loss rate is proportional to the temperature difference between the body and its surroundings. This law has become a guiding principle in the field of thermodynamics. 

7. Newton is, of course, best known for his work on understanding gravity

While the legend is that Isaac Newton discovered the principles of gravity when a falling apple hit him, that story is probably apocryphal or only has a grain of truth. 

Whatever happened, Newton realized that some force must be acting on falling objects, like apples, because otherwise, they would not start moving in the first place (see Newton's First Law of Motion).

Newton publicized his Theory of Universal Gravitation in the 1680s. It set forth the idea that gravity was a predictable force that acts on all matter in the universe and is a function of both mass and distance. The theory states that each particle of matter attracts every other particle with force directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

As Newton also began observing planets, he realized that the moon should move in a straight line away from Earth unless there was a force keeping it close to our planet. This force was gravity.

8. Newton was instrumental in creating counterfeit-busting coinage

Newton was renowned in his day for his attention to detail and obsessive problem-solving tendencies. For this reason, he was considered the perfect choice for helping the British Royal Mint to help them solve a big problem - the development of a standardized coinage.

Newton was appointed as the Warden of the Royal Mint in 1696, and one of his tasks was to search out those attempting to forge coins. At that time in British history, such a practice was a grave crime, and anyone caught would face the death penalty.

The forgery issue also compounded the British economy's problems during the 1600s. Unlike today, the country's money was made from precious metals, like silver, whose value as a metal was often more than the coins' denomination.

This inevitably led to savvy Brits melting down or trimming off (clipping) parts of the coin to get some extra income. Technically called coin debasement, this is a practice as old as time, and a solution needed to be found.

The problem became so bad that people lost faith in British coinage, often leading to riots and other civil disorders.

In addition to fighting crime, Netwon ordered that all English coins in circulation be melted down and remade into a much more intricate design, too tricky to widely fake. His solution was to add ridges to the edges of coins (reeding), a practice copied by many other countries today.

While he did not "invent" this practice, his heavy-handed routing out counterfeiters and standardized reading on British coins was a quantum leap for the British coinage of the day.

9. Newton invented a reflecting telescope too

Quality and reliable scientific apparatus have always proved to be a critical component behind any great scientific discovery. For Newton, he lived at a time when equipment like telescopes was lackluster.

Even the highest quality of the day tended to distort the image to such a degree that making accurate measurements (and therefore predictions) was impossible to the accuracy demanded today.

Newton's experiments with colors showed him that different colors were bent at different angles by the lenses, making the image look fuzzy. Newton realized that it might be better to use mirrors instead of lenses to refract the light to improve the quality of his experiments.

He supposed that a large mirror would catch the image, and then a smaller mirror would reflect it into the viewer's eye. This method would give a clearer picture and let an observer use a much smaller telescope.

This would prove revolutionary, and although Netwon was technically pipped to the post by the Scottish inventor James Gregory, Newton was the first to put the theory into practice by building one for real.

Newton ground the mirrors himself, assembled a prototype, and presented it to the Royal Society in 1672. The device was only 6 inches (15 cm) long but eliminated much of the color refraction and had 40x magnification.

10. Newton's "Principia" was his greatest work

Newton was undoubtedly one of the greatest thinkers of all time with, as we have seen, some foundational work in the fields of physics and mathematics. But, arguably, his Magnus Opus was "The Principia."

Called the "Philosophiae Naturalis Principia Mathematica," to give it its full name, this groundbreaking piece of literature was first published in 1687. This work brought all of his discoveries up to that point into one "grand theory" of his work on motion and gravity to make broader sense of the world and the universe around us.

This work, in part, helped Newton show that the Earth was not at the center of the solar system but rather that it moved along with other planets and orbited around the Sun, among other principles more commonly referred to as Newtonian Physics.

This was a bold and ambitious undertaking, and very few people have even attempted, let alone come close to achieving. Newton, however, managed it.

A similar feat wouldn't be attempted again until another great mind, Albert Einstein, created his "General Theory of Relativity" several centuries later.

And that is your lot for today.

Isaac Newton was a mind well ahead of his time and one of the most prolific and revolutionary thinkers in human history. His discoveries forged many aspects of modern mathematics and physics, and the fruits of his mental labors still touch us today.

The modern world would be very different if he decided to take up farming!