A gerb one of the most common pyrotechnic effects

What it looks like

A gerb looks like a fountain of sparks, that usually lasts for 5-15 seconds (the "bursts" of sparks are called jets, but basically work the same way) They are pretty much soundless or make a hissing sound.

The sparks are usually silver or gold coloured, but they can also be just about any other colour of the rainbow

How it works

A gerb is a cardboard tube that contains a mixture of propellant (usually the same stuff used in rocket engines for model rockets), burning material (magnesium) and colourant:

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