Around 2,500 years ago, the Greek philosophers Leucippus and Democritus suggested that matter (= everything that has weight and takes up space) is made up of extremely small building blocks surrounded by empty space.

These fundamental elements, which contained no smaller components within them, were called atoms, which means indivisible in Greek.

The idea that the atom was the fundamental building block of matter persisted for a long time, but without concrete proof. The existence of atoms was demonstrated in 1804 by John Dalton, who, to explain his experiments, imagined atoms as solid, hard spheres with different weights.

At the beginning of the 20th century, it was discovered that the atom is not the fundamental building block because it contains even smaller particles: electrons and the nucleus. The nucleus is composed of protons and neutrons, which are, in turn, made up of quarks.

The elementary particles whose existence has been demonstrated are of two types: fermions and bosons. Bosons are named after the Indian physicist Satyendra Nath Bose, and fermions after Enrico Fermi, one of the greatest Italian physicists.

• Fermions: particles that make up matter, such as electrons, neutrinos, and quarks.

• Bosons: energy-carrying particles that govern the forces of interaction between fermions. For example, photons are the bosons associated with electromagnetic interactions.