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Get Outside at Night: Experimenting with Light

During the autumn months the days begin to get shorter. Take advantage of our extra hours of darkness with these light-generating experiments. An outside place like your own backyard provides the perfect laboratory to learn about flammability, the piezoelectric effect, and triboluminescence.

Activity 1: Citrus Flames

Photos of orange peel experiment

This activity is to be only performed by an adult or direct supervision of an adult as it involves fire.


  • Oranges
  • Tea candles
  • Matches or a lighter
  • Knife

The purpose of this activity is to demonstrate that orange peels have a highly flammable oil called d-Limonene. Why do oranges have this oil? Much like another form called  l-Limonene that makes citronella, it acts as an insect repellent to protect the oranges from small pests.  

In order for this demonstration to work, you must use a knife to cut the orange into four quarters and have the fruit removed, leaving only the orange peels. After acquiring the orange peels, find a flat, smooth surface on the ground outside in the dark and set down a tea candle or any other small candle. Using a lighter or matches, light the candle and give it around 30 seconds for the wick to burn at a normal rate. Once your eyes are a bit more adjusted to the dark, take one orange peel at a time, with the orange outside peel facing the flame, and hold it about 2-3 inches away from the flame.  The next step is to twist the peel so that the oil sprays the candle and you will get a small, bright, warm flame burst that lasts for about half of one second. While it doesn’t last very long it is quite impressive and leaves the area pleasantly smelling like oranges. You may repeat the demonstration until you run out of orange peels.

Activity 2: Quartz and the Piezoelectric Effect


  • 2 pieces of quartz mineral which can be found on the forest floor in wooded areas. Quartz crystals also work well and can be purchased online for less than 10 dollars.

The purpose of this activity is to observe a phenomenon called the piezoelectric effect. This effect happens in certain solid materials such as quartz when physical stress and compression is applied. In the case of quartz it gives out a faint spontaneous glow. Many people have called this a “spark” before, but this effect is not flammable and doesn’t generate any warm heat. 

In order to observe this type of energy, called piezoelectricity, you will need to make sure that your backyard is very dark and that there are no sources of light coming into the area. Take a piece of quartz in each hand and rub them together or strike them together while you observe the faint temporary glow.

Activity 3: Wintergreen Lifesavers


  • Wintergreen Lifesavers candy

The purpose of this activity is to demonstrate how the components of wintergreen candy combine to create a spark when the candy is crunched. Two things happen when you crunch Lifesavers. First, triboluminescence is a phenomenon in which light is generated when materials, in this case sugar candy, are crunched or manipulated apart. While not fully understood, it is thought to be caused by static particle charges, much like lightning. All hard candy could cause this phenomenon which is only observable in the dark, but the brightest glowing sparks happen with wintergreen Lifesavers. Why is that? The second reaction is that the wintergreen oil, known as methyl salicylate, amplifies the visible light from the triboluminescence by converting light wavelengths to a more visible longer wavelength, similar to the way fluorescent light tubes amplify visible light.

All you need to do for this demonstration is to find the darkest part of the yard, then wait a few minutes to let your eyes adjust to the darkness. Smaller Lifesavers are better because they are easier to crunch. Put the candy in your mouth and crunch with your mouth open so the sparks can be observed. Do this at the same time with a friend or use a mirror and you’ll be able to see this cool effect!

Happy Fall, HabiChatters!

With winter on the way, we turn to topics that inspire us in this spooky season of decreasing daylight. In this issue, I’m happy to share an introduction to glow-in-the-dark living creatures, a phenomenon that has always been one of my favorite marvels of the natural world. DNR’s resident bat expert, Dana Limpert, collaborates on a native animal feature about our favorite flying mammals. Plus, Outreach and Education Assistant Edwin Guevara describes some entertaining and educational outdoor activities for these dark evenings, and we suggest some Natural Areas to visit in this perfect season for hiking.

Stay warm,

Sarah Witcher

Click here to have HabiChat—the quarterly backyard wildlife habitat newsletter from the Wild Acres program—delivered right to your inbox!

In this Issue

Natural Heritage Program Spotlight: Fall Swamps
Habitat Tip: Glow-In-The-Dark Backyards
Native Animal Profile: Our BFFs, Bats


Header image with carnivorous plants