Protons are subatomic particles that carry a positive charge and are found in the nucleus of an atom. Along with neutrons, they make up the majority of an atom's mass. Protons play a crucial role in determining the identity of an element, as each element has a specific number of protons in its nucleus. One of the key characteristics of protons is their positive charge, which helps to hold the nucleus together. This positive charge also plays a role in chemical reactions, as protons can attract and interact with other particles like electrons. In addition to their role in atomic structure, protons are also used in the field of medicine for proton therapy, a type of cancer treatment that targets tumors with high precision while minimizing damage to surrounding healthy tissue. Overall, protons are essential building blocks of matter and play a significant role in both the world of science and in practical applications such as cancer treatment.