Most people light candles when they get older. For our Nation’s birthday, we light up the sky with fireworks! Ever wonder what makes them burst into different shapes and colors? So do we, so let’s take a look inside one of them and please, nobody light a match!
A 3-inch aerial shell is the largest flying firework you can find in a neighborhood store or stand, but six-inch shells are what the professionals use. A 20-minute pyrotechnics display can shoot about 10,000 ball shells into the air. Typically, 60 percent of those fireworks cost around $50 each. Talk about burning cash!
The shells are packed with over a pound of explosives. Flammable star pellets are arranged in rings around the inside of the fireworks. Different chemicals make the stars burn in an array of colors. Also, the placement of these stars are what makes the different patterns in the sky. Certain chemicals also make the stars burn fast, slow, or even leave trails of fire behind them.
The shells get lowered into a fiberglass pipe called a mortar, with a fuse hanging out the top. Because timing is everything in these modern-day displays, these fuses have to go off fast! How fast? About 100 feet per second!
The lift charge at the bottom of the ball shell is the first to go, launching the firework to a height of over 300 feet. As it travels, a smaller, time delayed fuse gets lit inside the flying shell. When it reaches the desired altitude, the inner fuse ignites the charge inside the shell, exploding it and sends the stars scattered into shapes.
So, sit back and enjoy. Knowing the science behind these firework shows is cool, but staying safe is even better!