Yes, even Particles have their own history !

   In 1909 two physicists, Hans Geiger and Ernest Mardsen under the direction of Ernest Rutherford made the following experiment : they sent alpha particles on a thin metal foil made of gold atoms and checked how alpha particles would bounce back. I know, who on Earth would wake up and be like, I'm gonna send alpha particles on a sheet of gold... 

                                                               Rutherford experience

Well those guys did and made a breakingthrough discovery : atoms are made of a nucleus positively charged and electrons graviting around this nucleus. You may think, how great...everybody knows that. How else could an atom be. 

  Well untill that time most physicists thought that atoms were like a pudding where negative and positive charges would happily swim around. Too bad for those physicists to realize that positive and negative charges are like cats and dogs. Now, your cat may like your dog, but you got the point right...They don't share the same room. When electrons race around the nucleus (pretty far away) in their own clouds, positive charges are happier cuddling in the nucleus. 

                               illustration of positive charges cuddling....(that dude looks creepy though)

So now, you may ask me... so there's a cloud full of electrons, a nucleus where positive charges cuddle (orgie...lol), so... What's in bewteen ?

Well Ladies and Gentlemen, be ready for the greatest answer ever.... There's nothing. Not like when you open your fridge coming back from holiday and have to make the following sad statement : « there's nothing in my f***** fridge », not that kind of nothing. I'm sure, there's a beer left, a rotten tomato, some left over of chinese food.

                                               Hum....what am I gonna have for dinner?!      

 When I tell you there's nothing bewteen the electronic cloud and the nucleus I mean the void, total void, not even the smallest, slightess particle. NOTHING.

That was something to admitt for those guys. Matter is made of molecules. Molecules are made of atoms. Atomes are made of an electronic cloud, and a nucleus with Nothing in between !

                                                              atome: electronic clouds 

Now we know that matter is made of electrons and a nucleus.

Cool, but let's take a look closer.

What is the nucleus (but an orgie, yes yes, we talked about it before...) or should I ask, what's in the nucleus ? Rutherford -yes that same dude who discovered the structure of atom, some have it all- realized that the nucleus was made of protons and neutrons. Protons carry a positive charge and neutrons are electronically neutral. So here it is. We know a lot about atoms. And we're not done ! We can zoom more ! How exciting, how far are we gonna go. Well, sorry guys, this is gonna be the last zoom for now. So we know that electrons are fundamental particles, which mean that they cannot be decomposed into smaller pieces. However protons and neutrons are not ! They are made of smaller particles called quarks. Those guys however are fundamental particles. Fiou....we're done zooming !

A proton is made of two up quarks and one down quark and a neutron is made of two down quarks and one up quark .

So now we have three elementary particles :

the electron and the up and down quarks.

And this is just a very small piece of the puzzle.

During the 20^th century physicists putting their brains together established the existence of no less than 16 fundamental particles !!!! Plus the Higgs Boson that was discovered three years ago.

Basically there are two kinds of particles :

-Leptons which are particles of matter. like you can touch them. I mean if you were really, like really small.

-Bosons which are particles of forces. They carry forces. Okay, now you're like...wait, what are you talking about 0.0 So imagine you're on a boat. One of your friend is on another boat. (I'm talking about small boat, not yatch and stuff). You throw a ball to your friend. Let's also say you know how to throw and your friend knows how to catch a ball. So, you throw this ball, and your friend catches it. What is likely to happend is that your friend's boat may move away a little bit. You see, your ball was carrying some energy, some force and carried it to your friend's boat. Bosons kinda work the same.

So here is the standard model of particle physics.

                                                   Standard model of particle physics

There are 6 quarks, 6 leptons and 4+1 bosons, each boson correspond to a fundamental force.
g: Strong force (the one that keeps quarks together)
W and Z: Weak force
γ (also called photon) : electromagnetic force

So now you can try to put them together the same way you used to do with your lego when you were a kid...(Well there are some rules...but same with lego right...)

                                          Haha...We're so happy swimming in legos!!!! x_x

After a century of intensive reseach, gigantic installation like the CERN, the puzzle is finally completed!

Sophie in cognito