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# particleLifeSpanVariation

The range, in seconds, of randomized particle life spans. Animatable.

```
var particleLifeSpanVariation: CGFloat { get set }
```

## Discussion

Setting a nonzero value for this property randomizes the effect of the [`particleLifeSpan`](/documentation/SceneKit/SCNParticleSystem/particleLifeSpan) property. SceneKit randomly adjusts the life span of each particle by up to half the [`particleLifeSpanVariation`](/documentation/SceneKit/SCNParticleSystem/particleLifeSpanVariation) value. For example, if the [`particleLifeSpan`](/documentation/SceneKit/SCNParticleSystem/particleLifeSpan) value is `1.0` seconds and the [`particleLifeSpanVariation`](/documentation/SceneKit/SCNParticleSystem/particleLifeSpanVariation) value is `0.5` seconds, each particle appears for a random duration between `0.75` and `1.25` seconds before being removed from the scene.

The default value is `0.0` seconds, specifying no randomization.

You can animate changes to this property’s value. See [Animating SceneKit Content](/documentation/SceneKit/animating-scenekit-content).

---

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