Key idea
Nuclear fusion
Énergie libérée : E = Δm c²
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.
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
Key idea
Nuclear fusion
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Guided example
Nuclear fusion
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.
Put it into practice
Nuclear fusion
Choose a concrete case linked to Nuclear fusion. Write down the known information, what you are trying to find, and the units. Then state the rule, model or trend you will use. If a calculation is involved, keep the units visible at every line; if it is conceptual, state what changes and what remains fixed.
Check your answer
A strong answer contains four things: the starting situation, the variable that changes, the direction or numerical result, and one check. The check can be a unit, an order of magnitude, a limiting case or a comparison with a familiar example.