GlossariesIGCSE GlossariesIGCSE Physics GlossaryNuclear Fusion

Nuclear Fusion - IGCSE Physics Definition

Reviewed by: Leander Oates

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What is nuclear fusion?

In IGCSE Physics, nuclear fusion is a process in which two light atomic nuclei combine to form a heavier nucleus, releasing a large amount of energy in the process. Nuclear fusion occurs naturally in stars, including the Sun, where hydrogen nuclei fuse to create helium.

Illustration of nuclear fusion; two nuclei collide, indicated by a burst, forming a larger nucleus and releasing energy, marked by an arrow and "energy".
Two hydrogen nuclei fuse to form a helium nucleus

In a nuclear fusion reaction, a small amount of the mass of the particle is converted into energy. The energy released in a fusion reaction is far greater than the energy released in a fission reaction.

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Leander Oates

Reviewer: Leander Oates

Expertise: Senior Physics Content Creator

Leander graduated with First-class honours in Science and Education from Sheffield Hallam University. She won the prestigious Lord Robert Winston Solomon Lipson Prize in recognition of her dedication to science and teaching excellence. After teaching and tutoring both science and maths students, Leander now brings this passion for helping young people reach their potential to her work at SME.

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