Fusion
Physics: Cambridge International GCSE Supplement, topic 1.11.10
Fusion
Nuclear fusion is when two light nuclei fuse together to form a heavier nucleus. The Sun’s energy comes from nuclear fusion.
Nuclear fusion
- Nuclear fusion is the process where two light atomic nuclei combine to form a heavier nucleus.
- This releases a large amount of energy.
- Fusion is the same process that powers the Sun and all other stars.
- Fusion reactions require extremely high temperatures and pressures to occur.
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Fusion in the sun
- The Sun's core is a big natural fusion reactor.
- Extremely high temperature and pressure forces hydrogen nuclei to form helium, releasing energy.
- A small amount of mass is lost during this process.
- This mass is converted into a huge amount of energy (E = mc2).
- This energy travels from the Sun and gives Earth light and heat.
Fusion on earth
- Scientists are researching how to use fusion to produce electrical energy.
- Fusion could provide a large-scale, clean energy source.
- Fusion power plants would not produce long-lasting radioactive waste like nuclear fission plants do.
- The fuel for fusion, such as isotopes of hydrogen, is easily available (e.g. from water).
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Challenges of fusion
- Fusion requires extremely high temperatures and pressures, like in the Sun.
- On Earth, it is difficult to keep the plasma hot and confined long enough without melting the walls.
- Scientists are still working on building a reactor that can produce more energy than it consumes.
Test yourself on Fusion
What is nuclear fusion?