# Classical analogy of particle decay

Is there some classical system that mimics the decay law for particles $N(t)=N(0)e^{-(Q_1+Q_2..)t}$ with multiple decay modes? To help me visualize this process. Something like a barrel of water with holes in it, where the areas of a holes are $Q_i$ representing the branching ratios, but this didn't quite work because the barrel eventually becomes empty.

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Any random process with a constant probability per unit time will give you an exponential decay. A classic, though morbid, example is animal death (the death rate being roughly constant after infancy and before old age). In your case $Q_1,\ Q_2,\ldots$ could represent different causes of death (disease, predation, etc.). –  Michael Brown Mar 4 at 9:54