Graphite (what makes up the pencil tip) and diamonds are both made out of carbon. But, even though they are made out of the same element, graphite breaks very easily (that’s why we use it for pencils) and diamond is extremely hard. How? It is because of the arrangement of the atoms. Atoms are the tiny building blocks of almost everything in the universe. These atoms are bonded or connected in a certain way which affects the strength of a material (you can listen to our episode about atoms and molecules here). The atoms in graphite are arranged in straight sheets while the atoms in diamonds are arranged in a crystal structure which is in triangular prisms. That shape makes the material stronger or weaker!!