A question
What makes fireworks different colors?
A calm, true answer. Then, if the wondering keeps going, the whole episode.
The short answer
Metals. Each colour is a different metal packed into the shell, and each one glows its own shade when it burns: strontium red, copper blue, barium green, sodium yellow.
The heat pushes energy into the atoms, and they let it go again as light. The exact colour depends on which metal it is. People have been mixing these glowing powders for more than a thousand years, long before anyone knew why they worked.
Go deeper tonight
Fireworks: The Earth Painting the Sky
The full episode, in one calm voice, with nothing that startles.
Read the guide for this one in the morning.
This connects to
One idea turns up in many different nights. Follow one and the library starts to join up.
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