Top 10 Greatest Physics Experiments: 6. Newton's Prism

In number 6 we have another giant of physics – Isaac Newton. Newton is famous for his theories on dynamics of moving bodies, invention of calculus and the law of gravitation. However, not many people know that Newton also did many important experiments while investigating the properties of light.

Even though light is not completely understood even today, back in the 17th century, people actually new quite a lot. Ever since the times of Aristotle it was believed that light had some kind of a purest form (or colour), which somehow get’s altered to form other colours. It was believed that rainbows were somehow formed using this principle.

Newton decided to test this prediction by shining a ray of white light through a glass prism. And the result of this is one of the most beautiful experiments in the history of physics.

So what really happens is that white light, which is made up of all the main colours (Red, Orange, Yellow, Green, Blue, Indigo, and Violet) when going through the prism, splits up in the mentioned colours, all leaving the prism at different angles. This is due to the fact that light changes speed when entering a different medium like glass. This depends on a thing called the refractive index of a material, which is different for different colours and different materials. Thus all the colours that make up white light refract at different angles, which is exactly what causes a rainbow pattern to appear.  

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Strangest Facts of Physics: Most of the Universe is Missing

Isaac Newton, inspired by the falling apple in his yard during the Great Plague, created his greatest work – the law of gravity. This wonderful and simple law predicted the movements of planets, stars and even galaxies.  Even though, Newton’s calculations could precisely predict movement of any stellar object, the great genius had no idea how gravity actually worked.


More than 3 centuries later perhaps the greatest physicists ever, Albert Einstein, created his famous special and general theories of relativity. Even though Newton's law of gravity was very precise, there were some cases when movement of the planets and galaxies could bot be explained by this simple law. However, Einstein's general relativity combined with Newton's laws could explained almost all the movements of the planets, stars and galaxies. The great thing about these theories is that they can be used to find out more about the universe. For example by observing the rotation of the outer stars in the galaxy, scientists could calculate the total mass of the galaxy.
This is where the whole  strangeness started. When calculating, the mass of various galaxies scientists realised that those galaxies move in such a way as if there was more mass in them than we can observe. This meant that either there was something wrong with current theories and calculations or there was some invisible matter, which interacted only gravitationally. And since Einstein's theories have been tested and proved dozens of times, scientists came to the conclusion that there is some kind of strange invisible matter called dark matter. This is our strange fact of today. 


Even more shocking is that there is almost 6 times more dark matter than ordinary matter in our universe. This means, that even now, there's invisible dark matter in your room, which cannot be seen or detected in any way, except gravitationally. 


What the universe is made of:

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How to Learn Calculus The Simple Way

So I guess it's safe to say that calculus is one of those topics, which are for some reason really hard to grasp for most of the students in high school and later in college. Maybe, it's because calculus is really a unique branch of mathematics, that is, it's different from most of the mathematics that we are taught in high school (most of which was developed by ancient Greeks, of course with some slight improvements by later mathematicians). After all, it was developed by greatly gifted mathematician and scientist Isaac Newton (and Leibniz too).

I myself remember having some problems with calculus. It's not that I didn't grasp the mathematics, it was just most of the time I didn't have the feeling what I was calculating, or what's the sense of derivatives, integrals and so on. And what really helped me, when I was revising before going to college, was some great books and video lectures.

Firstly, I really enjoyed these simple YouTube lectures by Prof. R.Delaware. I like this guy because he really doesn't presuppose that you have some past knowledge about calculus (except of course some basic mathematics from high school), he simply explains everything as it was being explained for the first time.

These lectures cover all the basic high school calculus and some of the basic college calculus. Basically the two main parts are differentiation and integration.

So here's the first lecture:

And you can find all the other lectures on calculus and other topics HERE.

If you're looking for a book specifically that would help you with calculus I highly recommend Calculus for Dummies. It's a very basic and fun to read book, which will give you all the required knowledge of high school and some college calculus. Also it contains very nice diagrams, which give you a great visualisation of calculus concepts. Also it contains some neat tricks how to do calculus problems.

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