The atom

Imagine cutting an apple in half, than cutting each half in half and so on for a million times. (supposing you have a knife small enough)

After a few billion years, you will find that you have nothing left to cut. You have reached the smallest part in the Universe: the mighty atom.

For centuries, scientists have considered atoms as being the smallest things possible. Until someone found that you can "cut" even further, and a new, strange world was revealed...

EVERYTHING is made up of atoms. Buildings, trees, cars, dogs, your body, the air, THEY ARE ALL MADE UP OF ATOMS.

The atom's size
Atoms are very small. A row of a half-a-million atoms can be covered by the thickness of a string of hair, while a drop of water contains about 300 billions billions atoms. In order to see the atoms in a water drop, you must zoom in until the image would reach 320 km in wideness.


How does an atom look like?
The atom is much too small to reflect light, so this question has no sense. Even so, pictures of the electric field around singular atoms can be obtained.

For how long can an atom live?
Atoms are almost indestructible. When you die, the atoms in your body do not disappear, they are recycled. Approximately, a billion of your atoms have been in Newton's or Aristotel's bodies. No-one knows for sure for how long an atom can live, but a scientist considers that 100 000 000 000 000 000 000 000 000 000 000 000 years is a pretty fair number...

How have atoms been discovered?
The first proof of the atoms' existence was found when scientists had discovered that chemical substances always combine in precise proportions. Later, they found out that the variation of pressure and temperature of a gas can be explained if considered that the gas is made up of billions of elastic particles.

Can you divide an atom?
200 years ago, when atoms have been discovered, scientists considered that they couldn't be divided. But they can be "opened". Dividing an atom's core (it's nucleus) is, after all, pretty difficult. It can cause a nuclear explosion.

What are molecules?
Atoms tend to unite. They attract each other with huge forces and can join, forming a molecule. A water molecule (H₂O) is made out of 3 atoms - a bigger one, oxygen, and 2 smaller ones, hydrogen. Almost everything is made up of molecules.