Candle wax melts due to the open flame’s heat. This molten wax gets sucked into the candlewick due to capillary action. This liquid wax then turns into Carbon Dioxide and water vapor upon combustion with Oxygen. This is because candle wax is basically hydrocarbons that combine with oxygen to form CO2 and H2O.
This is how the wax ‘disappears’ and the candle reduces in size. In addition to CO2 and H2O, candles produce negligible amounts of Carbon Monoxide too.
Have you ever wondered about the process behind candle burning? Where does all the wax go? Why does it seem to disappear into thin air?
In this article, I’ll try to explain the science behind a burning candle. Don’t worry I’ll make sure it doesn’t read like a middle school science book.
We need to discuss how a candle works and the principles involved in candle burning.
Where does all the wax go when you burn a candle?
Candles generate light by generating heat. The heat/light generated by a candle is because of the combustion of the wax with the Oxygen in the air.
If you wanna know where all the wax goes when burned, we need to discuss the nature of the candle wax and the process behind candle burning.
What actually burns in a candle?
Wax is made of chemicals and has a carbon base as it’s made from Petroleum. Wax is essentially made of Hydrogen and Carbon elements.
Most people look at wax as, well, just wax. If you keep in mind that it’s just Hydrogen and Carbon, it changes your perspective.
Is burning a candle a chemical or physical change?
Candle Burning is a chemical change. Hydrogen and Carbon in the wax react with Oxygen in the air to give rise to Carbon Dioxide and Water(Steam).
Candle Melting is a physical change. Solid wax changes its physical state upon heating and turns into liquid wax.
What happens to the wax when a candle burns?
The heat from the burning wick melts the wax. The melted wax particles/Hydrocarbon particles react with Oxygen to form Steam and CO2.
The wax never burns in a perfect manner. This is the reason for the generation of smoke by the candle.
If you observe the flame closely, you’ll notice that it’s blue-colored at the center. The blue flame is surrounded by an orange flame which in turn is surrounded by a yellow flame.
The blue flame indicates the perfect combustion of the wax. This perfect combustion releases only steam and CO2, as you can see if you observe closely.
Does Wax evaporate in a Candle?
Wax turns into Steam and Carbon Dioxide upon burning. These gases then evaporate into the surroundings. Wax is made of Hydrogen and Carbon. These elements combine with Oxygen in the air to give rise to Water(Steam) and CO2.
Think of wax as Hydrogen and Carbon elements. Wax is made from petroleum, so it essentially has Hydrocarbons in it.
If you keep this in mind, everything about candle burning becomes clearer.
Candles generate light by generating heat. The heat produced by the burning wick melts the wax. The molten wax reacts with Oxygen in a reaction called Combustion.
Does Soy wax evaporate?
Yes, Soy wax evaporates into Water vapor and CO2. The flame melts the wax and draws it up the wick, facilitating the combustion.
The molten wax reacts with Oxygen in the air and turns into water vapor and CO2. These are the gases that are produced upon burning Soy candles.
Do Scented Candles evaporate?
Yes, wax from the scented candles evaporates into water vapor and CO2. The wax melts due to the heat from the flame and wicks.
After combustion, the gases CO2 and water vapor are emitted. Water vapor carries fragrance with it.
Why do Candles evaporate but not Wax Melts?
Wax in Wax Melts does not evaporate as they don’t come in direct contact with an open flame like Candles do. In the case of Wax Melts, only the fragrance emanates from the wax melts, leaving the wax behind.
The open flame in a candle gets hot enough and melts the wax surrounding it, which evaporates later. The candle flame is basically sustained by the wax.
The wax doesn’t just disappear in the case of a candle. The wax is the fuel that keeps the flame alive in a candle.
What temperature does wax evaporate?
Candle wax evaporates at 200C. The surrounding wax melts due to the flame on the wick. The molten wax is sucked into the wick thanks to capillary action. This molten wax evaporates as it reaches the open flame.
Candle wax begins to melt somewhere between 80-180 degrees Fahrenheit. It is easily achievable by an open flame on a cotton wick.
Do you breathe in candle wax?
No, you don’t breathe in candle wax in its true form. Candle wax releases Carbon Dioxide and water vapor upon burning.
The candle wax first melts to become liquid. This liquid is sucked into the candlewick thanks to capillary action.
The molten wax then turns into Carbon Dioxide and water vapor upon contact with the open flame and Oxygen in the air.
So, you’ll only be inhaling water vapor and Carbon Dioxide. If a candle is burnt for an hour, 10gm of Carbon Dioxide is released into the surroundings.
Remember, not all the wax goes into combustion successfully. Some of the wax fails to burn properly, leading to the formation of soot and trace gases.
Essentially, CO2 and water vapor form 99.9% of the gases released. The remaining 0.1% comprises of Smoke, Soot & Trace gases.
Where does Soot come from?
Wax particles that are at the rim of the candle are flung away before they go through the combustion process.
These half-burned wax particles become the soot that’s seen by the naked eye after a while. The soot settles on the indoor furnishings.
The smoke produced by the candle is an aerosol, so it leaves a charring on the walls and black Carbon deposits on the ceiling.
Happy Molding 🙂