Year 11 - Science
Nuclear fission and fusion
Nuclear physics
Study Hub
Study Guides
This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit covers atomic structure, isotopes, radioactive decay, and half-life. It explores alpha, beta, and gamma radiation, nuclear fission and fusion, and the uses of radiation in medicine, highlighting differences between contamination and irradiation.
Lesson Summary
You will learn to explain how energy can be transferred from the nuclei of atoms to cause heating.
Key Notes
- Nuclear fission is the splitting of a large and unstable nucleus such as uranium or plutonium.
- A neutron fired at a uranium nucleus can cause nuclear fission that splits the nucleus and emits 2 or 3 more neutrons.
- The motion of all the particles shot out from a nuclear fission can cause heating by making other particles move faster.
- Neutrons shot out from a nuclear fission can split more uranium nuclei in a chain reaction.
- Nuclear fusion is the joining of two light nuclei to form a heavier nucleus with the creation of gamma radiation.
Vocabulary To Learn
- nuclear fission: the splitting of large nuclei to form pairs of smaller nuclei and some free neutrons, with the release of energy
- daughter nuclei: the smaller nuclei produced during nuclear fission
- chain reaction: a series of nuclear fission events, with each one triggered by a neutron from a previous nuclear fission
- nuclear fusion: the combining of small nuclei at very high temperatures with the release of energy
Common Mistakes To Avoid
- Radioactive isotopes disappear when they decay, so that in one half-life half the mass is lost.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
Nuclear fission is the splitting of a large and unstable nucleus such as uranium or plutonium. A neutron fired at a uranium nucleus can cause nuclear fission that splits the nucleus and emits 2 or 3 more neutrons.
2. Define this scientific word and use it in context. 'nuclear fission'
the splitting of large nuclei to form pairs of smaller nuclei and some free neutrons, with the release of energy. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Radioactive isotopes disappear when they decay, so that in one half-life half the mass is lost. Correction: Emphasise that the mass of the nuclei at the end of a nuclear fission or fusion are almost identical to the masses of those at the start. There is a very small difference, with mass being converted to energy according to E = mc².
More Lessons In This Unit
- Activity and half-life calculations Study Guide
- Activity and half-life calculations (including complex ones) Study Guide
- Evidence of atomic structure Study Guide
- Ionising radiation Study Guide
- Nuclear decay Study Guide
- Nuclear decay (including beta–plus) Study Guide
- Nuclear power Study Guide
- Nuclear power stations Study Guide
- Radioactive half-life Study Guide
- Unstable nuclei Study Guide
- Uses of radiation Study Guide
Browse all guides in the Year 11 Science guide library.