The scientific flash behind the fireworks

As you ooh and aah at the dazzling explosions of a fireworks display, there are three things going on that you probably wouldn't guess: The chemists who made those pyrotechnics designed most of them so they wouldn't explode, you’re actually seeing nature conserving energy, and most peculiar of all, when things are at their flashiest, you’re actually seeing the fireworks as they’re cooling down.

The rockets’ red glare, and all those bombs bursting in air, are the product of pyrotechnic chemistry that’s been refined ever since the Chinese first started using black powder for noisy fireworks to scare away evil spirits.

The basic ingredients in black powder and all fireworks are the same as they've always been: a fuel source and an oxidizer. The fuel’s job, like the wax in a candle, is to provide heat. The oxidizer is there to provide more oxygen that the ambient air can supply, to accelerate the reaction – to speed up the burning.