A dew drop is made up of many molecules of water (1021 or a billion trillion). Each molecule is made of an oxygen atom and two hydrogen atoms (H2O). At the start of the 20th century, atoms were the smallest known building blocks of matter.
Each atom consists of a nucleus surrounded by electrons. Electrons are leptons that are bound to the nucleus by photons, which are bosons. The nucleus of a hydrogen atom is just a single proton. Protons consist of three quarks. In the proton, gluons hold the quarks together just as photons hold the electron to the nucleus in the atom
