MAGICTORCH

STANDARDS

NGSS: Core Idea: LS1.A

CCSS: Reading Informational Text: 9

TEKS: 6.9C, 7.6, 8.5E, C.11

Glow-Stick Science

Find out how chemistry allows glow sticks to light up the night

October 31, 2016

By Jennifer Barone

ESSENTIAL QUESTION: What is a chemical reaction? Can you give an example?

Trick-or-treaters often carry glow sticks to make themselves more visible in the dark as they travel door-to-door. But how exactly do these Halloween staples produce their eerie glow? They rely on chemical reactions, which occur when substances interact and change to create new substances. Some chemical reactions—like those happening inside glow sticks—give off light. This process is called chemiluminescence (ke-mee-loo-mih-NEH-sens).

Trick-or-treaters carry glow sticks as they travel from door to door. This makes them more visible in the dark. But how exactly do these sticks make their eerie glow? They use chemical reactions, which occur when substances mix and change to create new substances. Some chemical reactions—like those happening inside glow sticks—give off light. This process is called chemiluminescence (kem-mee-loo-mih-NEH-sens).

A glow stick is made of a flexible, transparent plastic tube filled with a dye solution, a liquid mixture made up of two or more substances. The tube also holds a smaller glass vial that contains hydrogen peroxide—the same chemical used to treat cuts and scrapes. To activate the glow stick, a person bends the tube, breaking the vial inside. This allows the different chemicals to mix. Once they come in contact with one another, they react and glow. Glow sticks keep making light until all the chemicals inside them react, anywhere from 4 to 12 hours.

A glow stick is made of a flexible, see-through plastic tube. It’s filled with a dye solution, a liquid mixture of two or more substances. The tube also holds a smaller glass vial that contains hydrogen peroxide. That’s the same chemical used to treat cuts and scrapes. To turn on the glow stick, a person bends the tube. This breaks the vial inside, and the different chemicals mix. After they come in contact, they react and glow. Glow sticks keep making light until all the chemicals inside them react. This takes anywhere from 4 to 12 hours.

HOW A GLOW STICK WORKS

Bending a glow stick breaks the glass tube inside it. This releases hydrogen peroxide.

The hydrogen peroxide reacts with the phenyl oxalate ester. It creates an unstable compound that breaks down and releases energy.

The energy excites negatively charged particles called electrons in the atoms of the dye molecules.

This causes the molecules to release the extra energy as light.

HOW A GLOW STICK WORKS

Bending a glow stick breaks the glass tube inside it. This releases hydrogen peroxide.

The hydrogen peroxide reacts with the phenyl oxalate ester. It creates an unstable compound that breaks down and releases energy.

The energy excites negatively charged particles called electrons in the atoms of the dye molecules.

This causes the molecules to release the extra energy as light.

Edwin Chandross, a chemist at the research company Bell Labs in New Jersey, first discovered the reactions needed to make glow sticks light up in the 1960s. The same type of reactions are still used today. Glow sticks now come in a variety of colors, from green to red to blue, depending on the type of dye they contain. And the sticks aren’t used just for fun. Military personnel, emergency responders, and underwater divers rely on glow sticks to see in dark places and alert others to their presence.

In the 1960s, Edwin Chandross discovered the reactions that make glow sticks light up. He worked as a chemist at the research company Bell Labs in New Jersey. The same type of reactions are still used today. Glow sticks now come in different colors. They range from green to red to blue, depending on the type of dye they hold. And the sticks aren’t used just for fun. Military personnel, emergency responders, and underwater divers rely on glow sticks. The light helps them see in dark places and lets others know where they are.

COLOR CHEMISTRY

Different dye molecules inside glow sticks produce different colors. The molecule shown here creates an eerie green glow.

COLOR CHEMISTRY

Different dye molecules inside glow sticks produce different colors. The molecule shown here creates an eerie green glow.

NAME THAT GLOW

Chemiluminescence is just one way to produce light. Here are some others.

INCANDESCENCE: A substance like the metal tungsten (W), used to make the filaments in conventional light bulbs, gives off light when heated.

FLUORESCENCE: A substance like the coating on the inside of a fluorescent light bulb absorbs one wavelength of light and quickly releases another.

PHOSPHORESCENCE: A substance like zinc sulfide in glow-in-the-dark stickers absorbs light energy and releases it over an extended period of time.

RADIOLUMINESCENCE: A substance like a phosphor releases light when hit with ionizing radiation (high-energy particles or waves).

BIOLUMINESCENCE: Chemical reactions produce light inside a living organism.

NAME THAT GLOW

Chemiluminescence is just one way to produce light. Here are some others.

INCANDESCENCE: A substance like the metal tungsten (W), used to make the filaments in conventional light bulbs, gives off light when heated.

FLUORESCENCE: A substance like the coating on the inside of a fluorescent light bulb absorbs one wavelength of light and quickly releases another.