The Power of the Nucleus
⚡ The Power of the Nucleus
Physics glossary
- What is nuclear fusion?
- The joining of two small, light nuclei to form a larger nucleus, releasing energy
- What is nuclear fission?
- The splitting of a large, unstable nucleus into two smaller nuclei, releasing energy and neutrons
Nuclear fission is the splitting of a large, unstable nucleus into two smaller nuclei. When a slow-moving neutron is absorbed by uranium-235, the nucleus becomes unstable and splits. The products are two medium-sized nuclei (fission fragments), 2–3 free neutrons, and an enormous release of energy.
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🧠 Memory Aids
Fission vs Fusion: "FiSSion = Splitting (two S's like a crack). FuSion = fuSed together." Or think: "Fission is like dividing cells (divides); Fusion is like welding (joins)."
Nuclear reactor components: Use the mnemonic FMCC: Fuel rods, Moderator, Control rods, Coolant. Each has a specific job: fuel provides the fissions, moderator slows neutrons, control rods absorb them, coolant removes heat.
Why fusion needs extreme temperature: Positive charges repel. To push two positive nuclei together, you need enormous kinetic energy (temperature). The Sun's gravity helps; on Earth we need magnetic confinement. Think: "Fusion needs to force FURY — 100 million degrees FURY."
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Quiz · Question 1 of 13
What is nuclear fission?
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This topic in real past papers
Every real exam question we've found on nuclear fission & fusion, with a full worked answer.