Almost everyone loves fireworks. When admiring the brilliant colors exploding in the sky, have you ever wondered where this colorfulness comes from?
Fireworks are colorful because of their ability to give off different wavelengths of visible light. Fireworks contain many types of metals, all with different atomic structures. When fireworks are burned, the metallic atoms inside are energized. And when the atoms relax back to their low energy state, they give off light.
Every atom has a unique atomic structure, so each type of metal will emit a unique “signature” in different wavelengths of light. The red light in fireworks comes from strontium atoms, blue is from copper, and yellow is from sodium.
Just as the red light tells us there is strontium in the burning fireworks, the wavelengths of light emitted by other materials can tell scientists atomic information about its stimulated source, too. But unlike fireworks, this light can’t always be seen by the naked eye. In this sort of source identification, scientist use detectors sensitive to non-visible light, like x-ray waves.
By measuring the wavelengths of x-rays emitted from a stimulated material, scientists can work backwards and figure out what atoms (and what materials) correspond to those signature ray emissions. Knowing the intensity of each emission, they can also calculate the concentration of each component material. This technique is called x-ray fluorescence spectroscopy. The name “x-ray fluorescence” refers to the x-ray-stimulated light being emitted from atoms.
Modern industry relies heavily on x-ray fluorescence spectroscopy to examine the composition of all kinds of materials. The mass production of composite materials like cement, for example, involves composition analysis like this – both of the raw materials and products at each processing stage. This technique can also be used to examine heavy metal concentration in food products, keeping our food safe.
The world is filled with hidden beauty, attracting scientists to uncover its secrets and use them to benefit human life. Our knowledge of light emissions illuminates the hidden chemical composition of materials around us. And these secrets make the beautiful firework blooms in the night sky shine even more brightly.