Nuclear fission
A large nucleus, such as uranium-235, absorbs a neutron and splits into two smaller nuclei, releasing energy and more neutrons. These neutrons can split more nuclei in a chain reaction.
Last updated
Analogy
Dominoes that each knock over two more.
In practice
Nuclear power stations control the chain reaction to heat water into steam that spins turbines.
Practice
Flashcards
- What happens in nuclear fission?A large nucleus splits into smaller ones and releases energy.
Questions people ask
What is a chain reaction?
In a chain reaction, each fission releases neutrons that go on to split other nuclei, which release more neutrons. Left uncontrolled, the number of fissions grows rapidly and releases huge amounts of energy, as in a bomb. In a reactor, control rods absorb extra neutrons to keep it steady.
What are the pros and cons of nuclear power?
Nuclear power makes lots of electricity from a small amount of fuel and releases no carbon dioxide while running. However, it produces radioactive waste that stays dangerous for thousands of years, and accidents, though rare, can be very serious. Building a power station is also expensive.