Kids, did you know that you don't always need a wick and wax to make a candle? All you need for this alternative is a clementine and some olive oil. The clementine acts as a natural wick for the oil. A candle works by vaporizing wax or oil by burning, via a chemical reaction that produces water and carbon dioxide from oxygen and the carbon-based oil. It's a clean process that also yields heat and light.

You’ll need:

• clementine (you could try another citrus fruit)
• olive oil (you could experiment with other vegetable oil)
• an adult partner to use a long-handled lighter 

Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

The steps:

Cut the clementine in half and carefully peel away the fruit, leaving ALL of the white part, called the pericarp or albedo, intact and exposed.  This includes the edges near the rind AND the center piece. The pericarp consists primarily of pectin, which is a plant polymer like the cellulose you would find in an ordinary candle wick. The pericarp, by the way, is high in vitamin C. Your goal is to have half of the fruit peel intact, and dry. If you made a mess with the juice, dry your rind off.   Once the rind is prepared, pour a small amount of olive oil into the "candle."  It really doesn't take very much, plus you want the "wick" to remain well exposed and not drowned in oil.

Have an adult partner light the candle.  It might light right away or it could take a few tries. If the pericarp "wick" chars rather than lights, then rub a bit of olive oil into it and try again. Once the candle is lit, it burns very cleanly. Although the bottom shouldn’t get hot, you may want to place the candle on a heat-safe surface just to be safe. The candle should go out on its own once the oil is used up, but do not ever leave it unattended.
 
If desired, clean out the other half of the clementine, cut a hole in the top of the rind, and place on top of the burning bottom half.  The hole will ensure that the candle gets enough oxygen. Cutting into the rind is a nice way to add a decorative flair to the project.  Also, you may wish to watch a video showing how to make a clementine candle.

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Kathleen Carrado Gregar, PhD, Argonne National Labs 
[email protected]
April 2012

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References: 

Anne Marie Helmenstine at About.com: Chemistry
http://chemistry.about.com/od/funfireprojects/ss/Clementine-Candle.htm