Question

why fireworks produce sound?​

Answer 1

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The fireworks are filled with lead oxide, which turns into lead atoms as the firework explodes and heat up. These lead atoms vaporize in the huge heat and the vapours make the crackling sound as they expand.

Answer 2

Loud bangs, which are the most common, are created by confining the explosion inside a small shell. The gases expand much quicker than the speed of sound and thus, the cartridge explodes creating a bang.

Crackling noise in the firecrackers comes from lead oxide, which turns into lead atoms as the firecrackers explode. These lead atoms vaporize and the vapours make the crackling sound.

Whistling sounds takes place due to the narrow tube, which ensure a slow burning of the chemicals. Potassium Benzoate is the Potassium salt of Benzoic acid which is also used as a food preservative. The oxidiser and the Potassium Benzoate burn together, one layer at a time, and is slower than the speed of sound. This emits the gases produced in spurts in the empty half of the narrow tube, which vibrates and thus makes a whistling sound.