It was once thought that atoms were the smallest building block of nature. Then, protons, neutrons, and electrons were discovered, and THOSE were thought to be the smallest building blocks. Now, we know that there are even smaller particles yet.

Within every atom is a cloud of negatively charged electrons surrounding the positively charged nucleus. The nucleus is built of two types of particles: protons and neutrons.

Protons are positively charged, and attract the cloud of electrons, keeping the atom together. Neutrons are not charged at all.

Protons and neutrons are made of even smaller particles called quarks. There are six types of quarks, and they have funny names: Up, Down, Top, Bottom, Charm, and Strange. These particles are thought to be Elementary Particles, which means that they can’t be broken into smaller pieces.

So: quarks come together to makes protons and neutrons. Protons and neutrons come together to make a nucleus. A nucleus combines with electrons to make an atom. And, finally, atoms come together to make everything around us!