Behind the scenes of the dazzling light shows that make spectators “Ooh!” and “Ahh!” on the Fourth of July, are carefully crafted fireworks. Whether red, white and blue fountains or bursts of purple sparks, each firework is packed with just the right mix of chemicals to create these colorful lights.
Inside each firework is something called an aerial shell — a tube that contains gunpowder and dozens of small modules called “stars,” which measure about 1 to 1.5 inches (3 to 4 centimeters) in diameter, according to the American Chemical Society (ACA). These stars hold fuel, an oxidizing agent, a binder and metal salts or metal oxides — the source of the firework’s hues. A time-delay fuse ignites the gunpowder and bursts the aerial shell once the firework is midair, causing the stars to scatter and explode far above the ground, producing a shower of light and color.
Once exposed to fire, the stars’ fuel and oxidizing agents generate intense heat very rapidly, activating the metal-containing colorants. When heated, atoms in the metal compounds absorb energy, causing their electrons to rearrange from their lowest energy state to a higher “excited” state. As the electrons plummet back down to their lower energy state, the excess energy gets emitted as light. [5 Dazzling Facts About Fireworks]
Each chemical element releases a different amount of energy, and this energy is what determines the color or wavelength of the light that is emitted.
For instance, when sodium nitrate is heated, electrons in the sodium atoms absorb the energy and get excited. As the electrons come down from the high, they release their energy, about 200 kilojoules per mole (a unit of measurement for chemical substances) or the energy of yellow light, according to the website of the University of Wisconsin-Madison chemistry professor Bassam Z. Shakhashiri.
The recipe that creates blue includes varying amounts of copper chloride compounds. Red comes from strontium salts and lithium salts, and the brightest red is emitted by strontium carbonate, the ACA explained on their website.
Just like paints, secondary colors are made by combining the ingredients of their primary-color relatives. A mixture of blue-producing copper compounds and red-producing strontium compounds results in purple light, the ACA reported.
Adafruit has had paid day off for voting for our team for years, if you need help getting that going for your organization, let us know – we can share how and why we did this as well as the good results. Here are some resources for voting by mail, voting in person, and some NY resources for our NY based teams as well. If there are additional resources to add, please let us know – adafruit.com/vote
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.