Scientific Fun Facts About Candles

by Lebermuth, on Jun 03, 2019

 Ever wonder how a candle works? If so, continue reading to learn some fun facts about the science of candles.What makes a candle burn?

The answer lies in the wax. Waxes are made of hydrogen and carbon atoms. When a candle is lit, wax is pulled through the wick and vaporized by the heat of the flame turning the wax into gas. The flame's heat radiates back to the candle to create an ongoing process that continues until there is either no more wax or the flame is extinguished.

What causes a flickering flame?

When a wick is lit, the wax turns into a gas composed of water vapor and carbon dioxide. This process is called combustion. Once the process stabilizes, it burns cleanly as evidenced by a non-moving teardrop flame. What causes the flame to flicker is when it receives too much or too little air or fuel. Carbon particles that have yet to be burned escape from the flame before this combustion process is complete. These prematurely escaping particles, also known as soot, are the reason a flame flickers.

Why does the candle flame always point up?

Ever notice that there is only one shape of a candle flame? There is a scientific reason for the tear drop shape of a burning candle. As a candle burns, the surrounding air is heated and begins to rise. As the warm air rises, thus leaving a void, cooler air goes to the bottom of the flame to replace it. This process continues and is called a convection current. This current creates the shape of the flame. But get this! When a candle burns in space, the flame is spherical, because it is not subject to the earth's gravity. Without gravity, the convection current does not exist, because there is no up direction for the heated air to rise. [Insert mind blown sound effect here!]

What causes the different colors of the candle flame?

There are three regions and colors of a candle. Blue is at the bottom of the flame. This section is blue, because it is oxygen-rich. It is oxygen-rich because it is where the hydrocarbon molecules begin to separate into hydrogen and carbon atoms. Above the blue section is a dark orange-brown part of the flame. This region has little oxygen and is where carbon breaks down and begins to form into carbon particles. The rest of the flame is yellow comprising of most of the flame's color. The yellow part of the flame is most dominant and where the carbon particles ignite. Although the combustion process emits a wide spectrum of light, the human eye sees the flame as yellowish.

Now, you know the science behind how a candle works! Next time you're in the presence of a burning candle, remember these fun facts to impress your fellow candle enthusiasts.