Fusion Powers the Sun and Fission Powers Reactors
Fusion is the joining of things. In physics it means combining atomic nuclei, the opposite of fission.
Fusion is the process of joining two things into one. In nuclear physics it means combining light nuclei to form a heavier one, releasing energy — the reaction powering the sun. *Fission* is the opposite, splitting heavy nuclei, and is what current power stations use. Fusion produces far more energy per unit of fuel and no long-lived waste, which is why it is pursued so hard.
- The joining of things. *A fusion of styles.*
- Nuclear joining of nuclei. *Fusion research.*
- Melting. *The point of fusion.*
- Fusion cuisine — a blend of culinary traditions. *Asian fusion cuisine.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | fusion | Nuclear fusion. |
| Verb | fuse | Fuse the wires. |
| Adjective | fused | Fused glass. |
| Opposite | fission | Nuclear fission. |
| Related | infuse | Infuse the tea. |
How it is used in a sentence
- The sun runs on fusion.Hydrogen into helium.
- Fission splits, fusion joins.The basic distinction.
- A fusion of jazz and rock.Music.
Fusion and fission
- Fusion — joins light nuclei, powers stars
- Fission — splits heavy nuclei, powers reactors
- Fuel — fusion uses hydrogen isotopes, fission uses uranium or plutonium
- Waste — fusion produces far less long-lived radioactive waste
- Difficulty — fusion requires temperatures of millions of degrees
From Latin *fusionem*, a pouring or melting, from *fundere*, to pour or melt — the same root as *found* in the sense of casting metal.
Fusion or fission?
Fusion joins light nuclei; fission splits heavy ones. Both release energy, by different routes.
Why is fusion power so difficult?
Because nuclei repel each other, so extreme temperature and pressure are needed to force them together and to hold the reaction long enough.