Atoms are so small that it is difficult for the human mind to comprehend their size. Everything in the visible universe is made up of atoms, but the amount of atoms in that matter is incredible. Even more amazing is the fact that atoms themselves are not even fundamental particles, but are instead made up of even smaller bits of matter called quarks. One way to characterize the size of an atom to students is to take a relatively small object and show them that an unbelievable amount of atoms are inside of it.
Describe an atom, including the three main parts (electrons, protons and neutrons), as well as the fact that an atom is primarily empty space.
Choose a relatively small object and illustrate that it contains nearly unfathomable amount of quarks. According to the University of Illinois, an average pinhead contains around 500 million million atoms.
Discuss how atoms are not the smallest bits of known matter; the protons and neutrons in the atoms are made up of an even smaller particle called a quark.
Illustrate that atoms are characterized in size relative to one another. This is done by comparing their masses. An atom gets its mass from the protons and neutrons in its nucleus (electrons are relatively mass-less compared to quark-based particles).