Key concepts

Chemistry

Light

Static electricity

Fluorescence

Introduction

Did you know that instances of miniature lightning can occur in your mouth when you bite on a hard candy? Would it not be fascinating if you could observe these light flashes?

Lifesavers Wint O Green Mints might just be the tool we need to observe this science! Crush them, observe and detect what makes the flashes visible. How many sparks can you see?

Background

Lightning is a massive release of static electricity. It starts with icy raindrops rubbing against the air. This rubbing gives rise to static electricity, and sometimes the electricity can jump across an air gap. This is called a discharge, or spark. Within clouds or between clouds and Earth the discharge is huge; it heats the air to the extent that it glows with white light. That glowing white light is the lightning you see.

Miniature buildups of static electricity occur often. Maybe you remember your hair standing up after brushing it or clothes clinging together when they come out of the dryer. In both examples, rubbing created static electricity. Crushing particular crystalline structures like hard sugar or salt also gives rise to static electricity.

Whenever there is static electricity, a release might happen. You might have felt or seen a discharge when touching a metal doorknob after walking across a carpeted floor. Although releases occur often, we hardly ever see a light flash. The miniature releases excite the air around it, which then typically releases ultraviolet (UV) light, a type of light humans cannot see. It is only when there is a fluorescent substance around, which can absorb the UV light and reemit it as visible light, that we see a tiny light flash. And this is exactly what happens in lightning—and this activity as well.

Materials

Lifesavers Mints—Wint O Green

Sugar Free Lifesavers Mints—Wint O Green

Lifesavers Mints—Spear O Mint and/or Pep O Mint

Other hard candy (optional)

Pliers

Dark room



Preparation

Bring all of your materials to the room you will be using for this activity, then prepare to turn off the light.

Note: The electrical discharges created in this activity are tiny and harmless. Although it is the same phenomenon, lightning in storms is created by huge discharges and is dangerous.



Procedure

Place one Lifesavers mint between a pair of pliers and turn off the light. Wait a minute or two to let your eyes adjust to the dark, then watch the candy as you crush it. Did you see anything?

Repeat with all other types of mints. Did you see anything happening as you crushed some types of Lifesavers whereas it did not happen when you crushed other types?

To confirm your findings, repeat the activity a few times. Does the same phenomenon happen each time with the same type(s) of Lifesavers Mint and not with others?

You probably detected it for only one of the types of Lifesavers you crushed. Can you find which combination of ingredients is responsible for the phenomenon? You will need some detective skills to find out! Where can you find the ingredients of each type of candy? In what way(s) are the ingredients of the mint that shows the phenomenon different?

Now, we will investigate what exactly creates the flash. Take another Lifesavers Mint, the type that exhibited the phenomenon, and start exploring. We know the flash happens when we crush the candy with pliers. Does it also happen when you rub two broken pieces together or when you press just enough on the pliers to put the candy under pressure without breaking it?

Extra: If you are wondering if it happens when you chew the candy, try it out. Chew this type of Lifesaver in a dark room in front of a mirror. Open your mouth wide between chews. Can you see a flash?

If you are wondering if it happens when you chew the candy, try it out. Chew this type of Lifesaver in a dark room in front of a mirror. Open your mouth wide between chews. Can you see a flash? Extra: Investigate other candies containing hard crystalline sugar and the special ingredient. Can you create a flash with those as well?

Investigate other candies containing hard crystalline sugar and the special ingredient. Can you create a flash with those as well? Extra: Try to create miniature lightning. Vigorously rub a piece of paper with wool for about a minute. Put a piece of metal (such as aluminum foil) in the center of the paper. Remove the paper and bring your finger close to the metal. Can you create a tiny spark?



Observations and results

Did you see a light flash when crushing the sugar-containing Lifesavers Wint O Green Mints but not when crushing the other types of Lifesavers Mints? This is expected. You need hard crystalline sugar as well as the artificial flavoring substance in the Wint O Green type to create the flash.

Crushing hard crystalline sugar creates static electricity, which can lead to a mini discharge, a kind of miniature lightening. You rarely see a light flash because the discharge is usually accompanied by ultraviolet (UV) light, a type of light humans cannot see. Note that many animals, like insects and birds, would observe this UV light flash because their eyes are sensitive to UV—but human eyes are not.

Lifesavers Wint O Green Mints (and maybe a few other candies) contain a fluorescent substance. Fluorescent substances absorb UV light and release it again as light humans can see. When crushing Lifesavers Wint O Green Mints, the UV light created from crushing the hard crystalline sugar gets absorbed by the fluorescent substance and released again as visible light humans can observe. Voilá—there is your light flash!

Although lots of hard crystalline structures emit UV light when crushed, the crystals in the sugar substitute do not. Therefore, no UV flash and thus no visible flash was seen when crushing Sugar Free Lifesavers Wint O Green Mints.

Cleanup

Wash any sticky parts of the pliers with soapy water and then dry thoroughly. Clean up any candy fragments in your work area.

More to explore

Attraction with Static Electricity, from Scientific American

Static Science: How Well Do Different Materials Make Static Electricity?, from Scientific American

Lightning: Just for Kids, UCAR Communications

This activity brought to you in partnership with Science Buddies