You may have wondered what happens to candle wax when it burns. Does it disappear into thin air, and are you breathing it in? Today, we’ll delve into the science behind burning soy wax candles to understand the combustion reactions and discover the fate of wax when a candle is lit. We’ll also explore why incomplete combustion reactions can cause smoking and discuss the meaning behind the colors of a candle flame.
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Table of Contents
Where Does the Wax Go When You Burn a Candle?
Regardless of the type of wax used in a candle, it mainly consists of hydrogen and carbon atoms, also known as hydrocarbons. When you light the candle’s wick, the wax heats up, melts, and is drawn up by the wick. The liquefied wax acts as fuel, sustaining the flame’s glow.
Specifically, the heat of the flame causes the solid wax to turn into a liquid and then a gas by breaking down the hydrocarbon molecules into separate hydrogen and carbon molecules. Once vaporized, these molecules rise into the flame, where they interact with oxygen in the air, producing heat, light, water vapor, and carbon dioxide. Approximately 25 percent of the energy released during the combustion reaction is emitted as heat. This heat is sufficient to melt more wax and sustain the combustion reaction until the candle is extinguished or the wick burns down.
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Why Does the Candle Flame Stutter or Smoke?
Sometimes, the combustion reaction doesn’t proceed perfectly, resulting in incomplete combustion when the candle receives either too much or too little fuel or air. This incomplete combustion can cause the flame to stutter or produce soot. It is more common right after lighting the candle when the combustion reaction is still stabilizing. However, after a few minutes, the candle flame usually burns steadily.
If the candle flame continues to stutter or smoke, it is advisable to check if the candle is burning properly. A wick that is too long can absorb excessive fuel (melted wax), which is why it’s important to trim the wick to ¼ inch each time before lighting. Additionally, ensure that the candle flame is not exposed to drafts or gusts, as they can cause uneven burning.
Rest assured, you need not worry about breathing in candle wax. The vaporized wax is only present around the candle flame and quickly dissipates once the candle is snuffed out. However, it’s still important to follow the aforementioned steps to ensure a clean-burning candle flame that doesn’t produce excessive soot, which may be unpleasant to breathe in.
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What Else Can a Candle Flame Tell Us About the Combustion Reaction?
When observing a candle flame, you’ll notice a blue area at the base. Here, the hydrocarbons vaporize into their component particles, creating a rich oxygen environment. As hydrogen separates, it combines with oxygen to form water vapor. Simultaneously, some carbon undergoes combustion to produce carbon dioxide.
Moving further up the flame, you’ll find a dark orange-brown section with lower oxygen levels. In this area, carbon continues to break down and forms solid particles, creating soot. The subsequent part of the flame is the familiar yellow color associated with candle flames. Here, soot formation persists until the particles ignite.
If you closely examine the candle flame, you’ll observe a thin blue halo. This blue edge represents the flame’s contact with oxygen in the surrounding air and is also the hottest part of the flame. Similar to the flame’s base, the blue color stems from the presence of oxygen.
As the candle burns, hot air rises within the flame while cooler, oxygen-rich air rushes in at the base to replace it. This continuous airflow gives the candle flame its elongated shape, pointing upwards. Without the influence of gravity, hot air doesn’t ascend. Candle flames appear spherical and mostly blue.
Candles are simple yet fascinating devices. To delve deeper into the world of candles and maximize their usage, check out our guide on how to burn a candle all the way down. The next time you light a candle, you’ll gain a newfound appreciation for the science behind its radiant glow!
