You know what happens when
your dad "accelerate" while driving: the car goes faster and faster!
Well, an accelerator does the same thing to particles (or antiparticles):
they speed up to very high speeds and that means they gain higher energy!
An accelerator is usually a ring shaped tunnel, but it can also have different
shapes. Particles moves through the middle of the tunnel, around and around,
over and over again. At each turn their speed increases a little, and
as they go round they gain all the energy needed for various experiments.
"Charge" is what we call a
fundamental property of particles. You are a boy or a girl - this is one
of your fundamental properties!
Any particle has either a positive charge, or a negative charge, or zero
Charge is one of the things that determines how particles behave when
they get close to each other:
- if they have the same charge they repel each other (positive-positive,
- if they have opposite charge they attract each other (positive-negative);
- zero-charge particles are neutral and can get close to anyone!
It's hard to picture "concentrated
But imagine what happens with the sun's rays and a lens.
Rays from the sun warm your skin (thermal energy). But a lens can concentrate
(or focus) the rays down to a small point. The same amount of energy is
in a much smaller space and now the sun's rays can burn you!
Paul Adrien Maurice Dirac
was born on 8th August, 1902, in Bristol, England. He studied electrical
engineering and mathematics, and at the age of 25 became a teacher at
He is best known for the famous "Dirac equation" which describes various
properties of the electron and predicts the existence of the positron.
When this prediction was confirmed, Dirac was awarded a Nobel Prize in
He was a very shy man and when informed that he had just won the Nobel
Prize told his boss that he did not want to accept it because he disliked
the publicity! (of course, his boss told him that refusing the prize would
bring him even more publicity!)
Energy is everywhere. The
sun gives us energy as light and heat. Fuels provide energy to power our
cars and planes and to heat our homes. Food gives you the energy you need
to run and play.
It's all different forms of the same thing: energy.
You cannot create or destroy energy, it's always there. But you can transform
it into the type you prefer - electrical energy to power your TV, thermal
energy to heat things up, mechanical energy to work your bicycle,…
And as energy can be transformed in so many different ways, no wonder
it can also transform into matter!
A physicist is a scientist
who try to understand the way nature works.
If you gave a physicist a marble, the physicist will wonder, what is it
is made of? Why, if you drop the marble, does it fall not fly? How does
it roll down a hill and how long will it take to get to the bottom?
He usually describes how things behave (move, fall, fly,…) with mathematical
A physicist can be a man or a woman, but always a very curious person!
There are different kinds of physicist too: some of them concentrate on
stars and planets (astrophysicists), some of them on rocks and mountains
on the Earth (geophysicists).
The one we are talking about here study the very basic constituents of
matter, which they call "particles", and their interactions at high energies:
they are called "particle physicists" or "high energy physicists".
You'll discover more about what they do by reading these pages!
The Antiproton Decelerator
is a new tool of CERN's physicists. It looks a lot like an accelerator
(ring shaped tunnel) but in fact it... decelerate antiprotons, i.e. it
slows them down! This way, their energy gets smaller, and physicists can
do many different kind of studies, including the assembly of antimatter's