Nuclear fission and nuclear fusion are two fundamental processes that release energy from atomic nuclei, though they operate in vastly different ways.

Nuclear fission refers to the process of splitting a heavy atomic nucleus into two or more smaller nuclei. A common example of this is the fission of uranium-235, which results in the production of smaller nuclei, typically accompanied by the release of neutrons and an immense amount of energy. This energy release is harnessed in nuclear power plants to generate electricity efficiently.

In contrast, nuclear fusion involves the combination of two light atomic nuclei to form a heavier nucleus. A prevalent example of fusion is the merging of hydrogen nuclei to create helium. This process naturally occurs in stars, where the extreme temperatures and pressures facilitate the fusion of hydrogen atoms into helium, resulting in a significant release of energy.

A key distinction between fission and fusion lies in the amount of energy released. While fission generates a considerable amount of energy, fusion produces even more energy per unit mass of fuel. However, achieving fusion on Earth presents considerable challenges due to the need for extraordinarily high temperatures and pressures to overcome the electrostatic repulsion between positively charged nuclei.

In summary, both nuclear fission and nuclear fusion play crucial roles in our understanding of atomic behavior and the mechanisms behind energy release from atomic nuclei.