# Sir Isaac Newton

## Sir Isaac Newton is regarded as the founder of classical theoretical physics. Find out about his achievements on this tour, which range from mechanics to aerodynamics and optics.

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### Biography

Isaac Newton was born on Christmas Day, December 25, 1643, on a farm in the province of Lincolnshire in the East of England. He studied mathematics and physics in Cambridge. At the age of only 26, he became Professor of Mathematics there. He died in 1727 at the age of 84.

### Interesting Facts

Although his mother wanted to make him a farmer, accompanied by an uncle, he visited the King’s School. The school’s master persuaded his mother that he should complete his education. In 1696, Newton moved from the university to the London Mint Office. In 1705, he received knighthood and was already President of the Royal Society.

### Gravitation Discovery

In 1665, Isaac fled to the country because of the plague. It is said that he sat down under an apple tree, and an apple hit him on the head. He pondered, “The apple falls to the ground because the earth attracts it. How far does this attraction go? To the moon? Maybe the power that attracts the apple to the ground also keeps planets on their orbit?”

### Color Spectrum

Can light be dismantled and reassembled? By experimenting with glass prisms, Newton discovered the spectral colors of sunlight. In 1671, he conducted many experiments with white light, which he then described extensively in his work "Optics."

### Gravitation Discovery

Astronomers have always wondered what keeps planets in their orbits in perfect proximity to other planets. Is it a magnetic force or a vortex of energy?

The English scientist Edmond Halley believed in a central force. Newton showed him the mathematical proof in 1684. Halley urged him to publish the findings. Thus, Newton wrote "The Mathematical Principles of Natural Philosophy.”

### It All Started With an Apple

The discovery that immortalized Newton happened by chance: while under a tree, a falling apple aroused his curiosity. Why does the apple always fall vertically and not to the side? And why are the sun and the moon not falling to the ground?

### Empirical Truth

For centuries, philosophers believed that the universe can be understood by pure thinking and deduction, starting out with a generalization and logically reaching a conclusion. Thanks to Newton, modern scholars started drawing conclusions not from abstract thinking but from empirical (experiential) analysis of physical data.

### Formula

Acceleration due to gravity on Earth, is 9.8 m/s² — it never changes, regardless of an object's mass. That's why if you were to drop a pebble, a book. and a couch off of a roof, they'd hit the ground at the same time.

### Newton’s Laws of Motion: Law of Inertia

Newton’s First Laws of Motion states: an object at rest will stay at rest, forever, as long as no force is being applied to it. Conversely, an object in motion will stay in motion, traveling in a straight line, forever, until another force is applied.

### First Experiment

Also, picture that the ramps are infinitely long and infinitely smooth. You let a marble roll down the first ramp, which is set at a slight downward slope. The marble speeds up on its way down the ramp.

### Second Experiment

Next, you are going to give a light push to a marble going uphill on the second ramp, which has a slight upward slope. The marble slows down as it is going up the ramp.

### Third Experiment

Finally, you push a marble on a ramp that represents the middle state between the first 2 — in other words, a ramp that is perfectly horizontal. In this case, the marble will neither slow down nor speed up. In fact, it should keep rolling. Forever.

### Law of Acceleration

When we have an equilibrium state — a total balance of all forces, objects do not accelerate. This is not the case with Newton’s Second Law. It takes into account 2 variables, which are the mass of the object and the net force.

### Net Force

A net force acting on a body produces an acceleration in the direction of the force. This acceleration is directly proportional to the force and inversely proportional to the mass of the body.

### Object’s Mass

Acceleration will increase when a larger force is exerted. The acceleration of an object is inversely proportional to its mass. If the cart was full of groceries, it wouldn’t accelerate as fast as it would if it were empty.

### Equation

The acceleration of any given object is directly proportional to the net force applied (as well as in terms of direction), and inversely proportional to the mass of that object.
a = Fnet / m

### “For every action...”

Newton’s Third Law states that if a body A acts on a body B with the force F, then the body B acts on the body A with an equal force. However, the directions of these 2 forces are opposite. All Newtonian laws are based on so-called axioms. The axioms of physics are not a result of pure thought but stem from experience and have proved themselves in their application to material reality.

### Action

Forces between bodies do not occur individually, but together. For example, if you want to accelerate a pendulum bob, you must exert a force. This way, you bring it out of equilibrium and release it, so it starts swinging.

### Reaction

However, the next bob counteracts your force, so the first bob is subjected to resistance. This resistance is called counterforce. A force (action) can never appear alone according to Newton; it always has a reaction force that affects another body.

### Interaction

If 2 bodies interact with each other, a force acts on each of the bodies. The forces are then equal and opposite. This is why our pendulum bobs swing back and forth in a singular motion, driven by this interplay of action and reaction.

### Color Spectrum

Just like sunlight, pure white light is made up of visible colors. This discovery was made by Newton in 1666 when he managed to split a beam of light through a prism. He punched holes in the curtains of his darkened room and began studying a beam of light passing through a prism.

### White Light Dispersion

Newton first used the word "spectrum" for the array of colors produced by a glass prism. He recognized that colors comprising white light are "refracted" (bent) at a unique angle and there is no "colored" light, color being in the eye of the beholder.

### Second Prism

Using a second prism, Newton demonstrated that each color in the spectrum is monochromatic and consists of a single unique wavelength that can't be separated into other colors. Newton's experiment also showed that light is composed of different colors.

### Complements

Using the 2 prisms, Newton found that some color combinations form a white colored light. As a result, they complete each other when mixed. These pairs of colors are called complementary. For example, purple and yellow combine to form white.

### Discovery of Calculus

Today, calculus is one of the most important fields of mathematics. However, 2 men in the mid-17th century claimed to be its inventor — Isaac Newton and Gottfried Leibniz. The ensuing dispute between them would embroil Europe in the greatest mathematical controversy of all time.

### Calculus

Calculus is the science of breaking patterns apart and piecing them together. Often, we reorganize them to discover something new. A circle can be broken apart into rings, and the rings turned into a triangle. This is an easy method to find a circle's area.

### Newton’s Discovery

Newton discovered the inverse relationship between the derivative (slope of a curve) and the integral (area beneath it). For him, the applications for calculus were geometrical and related to the physical world — such as describing the orbit of the planets around the sun.

### Leibniz (and Archimedes)

For Leibniz, calculus was more about analysis of change in graphs. His work was just as important as Newton's, and many of his notations are used today. Some scholars claim that Archimedes invented calculus first. The scroll with Archimedes’ version was discovered in 1908.

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