How do fireworks show chemical reactions?

The brilliant colors you see when the fireworks explodes comes from a wide variety of metal salts that are packed inside the firework. Now, when most people think of salt they're thinking of the white crystals they sprinkle on their food. That is a salt, but it's not the only salt. That's sodium chloride (NaCl). A salt is any metal atom bound to a non-metal atom. In the case of table salt, sodium is the metal and cholrine is the non-metal. When these salts burn they absorb energy, exciting electrons in the atoms. The excited electrons jump up to a higher energy level, but they are very unstable in that higher energy state. When the electrons relax back to their low energy state they release a photon of light. The color of light changes depending on the metal salt that is used. So, for example, strontium salts burn red, calcium shines orange, green is from barium, white is from magnesium, and copper shines a beautiful blue. Combinations of these salts yields the combinations of their colors (strontium and copper shines purple).