A staple for summertime activities- fireworks!
Where do they get their characteristic color from? I traveled down to the College of Charleston’s general chemistry lab to show you. What we’ll be working with is different metals, some of which you might find in your house- and setting them on fire. Michael Giuliano guides through the metal salts used in this experiment, called a metal flame test.
“This is table salt, a solution of sodium chloride,”
and some you probably don’t.
“Lithium chloride, barium chloride, copper bromide, and then potassium bicarbonate.”
“So what we’re going to demonstrate is that each chemical element that you find in things like fireworks has a fingerprint.”Michael Giuliano, C of C
To see that chemical fingerprint, we heat each sample over the blue flame of a Bunsen burner.
Sodium produces a brilliant orange.
Lithium a vibrant magenta.
Barium a pale whitish green.
My favorite, copper, burns with an electric bluish green with sparks of white.
And finally potassium a purple and pink flame.
Firework makers combine science and art by picking out certain elements in metal salts like these, arranging them in a certain way, and sometimes just combining them to create brilliant displays. Here’s a list of exactly what element is used for firework colors:
- RED– strontium or lithium
- ORANGE– calcium
- GOLD– iron
- YELLOW– sodium
- WHITE– magnesium or aluminum
- GREEN– barium with chlorine
- BLUE– copper with chlorine
- PURPLE– strontium and copper
But why do metals produce different colors? Here’s Michael with some Chemistry 101.
“Every element is defined by a characteristic cloud of electrons that surrounds it’s atoms. All of them sit at a very specific energy level, and when you give an atom energy, those electrons jump up a level. It’s kinda like giving a candy bar to a 3 year old. They jump up a level in their energy, and then they crash and come back down. And what we’re witnessing when we see color in a flame test is that crash of electrons coming back down from a higher energy level back down to their original state.”
In fireworks, the energy required to produce these colors is fueled not by a Bunsen burner, but high powered explosives and propellants that make fireworks so dangerous. Much like this experiment, safety comes first when handling fireworks- so be safe and enjoy their colors this summer season. As far as this flame test- don’t try this at home.
Storm Team 2 Meteorologist David Dickson