The Particle at the End of the Universe

From the very beginning, we’ve wondered what exactly our bodies are made of. Modern science has revealed that everything – including you – is comprised of tiny particles or building blocks called atoms.

And these building blocks are composed of smaller, subatomic particles: protons, neutrons and electrons.

Every single atom has a unique number of protons in its nucleus – its atomic number. This number can be used to identify the atom on the periodic table, first published by Dmitri Mendeleev in 1869.

For example, the atom Helium has two protons in its nucleus, and is thus identified with the atomic number “two.” Plutonium, on the other hand, has 94 protons (a “heavier” atom) and can be found on the table at number 94.

In 1913, Niels Bohr made an important contribution to our understanding of the atom with his atom model. He found that electrons “orbit“ around the nucleus and its protons and neutrons, much like the moon orbits the earth.

Protons and electrons differ in two important ways: charge and weight. Electrons are negatively charged and relatively light compared to protons, which are positively charged and 1,840 times as “heavy” as electrons.

An atom is the smallest unit for certain chemical elements. Sometimes, however, atoms can join together and form what’s called a molecule. Many common substances, such as water or carbon dioxide, are actually molecules, or a specific combination of atoms stuck together.

For example, when two hydrogen atoms join with an oxygen atom, they create a water molecule. You can think of this as the tiniest possible drop of water.

As miniscule as atoms are, however, scientists soon came to know of an even stranger, tinier world within the protons, neutrons and electrons themselves.