Nuclear fusion

The key idea

Fusion joins light nuclei into heavier nuclei. When the products are more tightly bound, the difference in binding energy can be released.

Why it matters

Fusion powers main-sequence stars, but achieving controlled fusion on Earth requires extreme conditions and careful confinement.

A picture to remember

Start with the central idea, then test it against a concrete element or example. A scientific model is useful when we know what it explains — and where its limits are.

The key idea

Fusion joins light nuclei into heavier nuclei. When the products are more tightly bound, the difference in binding energy can be released.

The key idea

Fusion powers main-sequence stars, but achieving controlled fusion on Earth requires extreme conditions and careful confinement.