"This T-Shirt is made of 9 million billion billion quarks"

Like all the matter we know, this T-shirt is made up of atoms, which in turn are made up of a nucleus surrounded by electrons. The nuclei are made up of protons and neutrons, which contain quarks. With no measurable size, electrons and quarks are elementary particles, meaning they do not contain any other particles. Their mass is so minuscule that a huge quantity of them is needed to make just a few grams of matter.

Find out more about the Standard Model.