Nuclear fission is the splitting of large atoms into smaller ones. It is a source of tremendous energy^*.

Uranium is a common fuel for nuclear fission.

• If a large mass^* of uranium atoms are split at the same time, the explosive energy of a nuclear bomb is released.
• If the uranium atoms are split in a controlled manner, the energy released can be used to heat water into steam. The steam, in turn, is used to turn turbines which generate electricity^* in a nuclear power plant.

Nuclear fission produces radioactive^* waste. This waste must be carefully controlled to avoid causing serious illness in people.