How does a candle burn?

The elements of a candle

Candles are much more than just decorative objects. They illuminate our living spaces and create a warm and soothing atmosphere. But have you ever thought about the science behind this soft light? Let's start by understanding the essential elements of a candle.

1. The Wick : It all starts with the wick, the thin piece of material in the center of the candle. Usually made of cotton, the wick plays a crucial role in the combustion process. It is through this that the heat necessary to melt the wax rises.

2. Wax : Wax is the main body of the candle. It can be made from a variety of materials, including paraffin, rapeseed wax, soy wax, beeswax, or other vegetable waxes. Wax is the fuel that burns slowly and produces light and heat.

3. Fragrance (optional) : In many scented candles, essential oils or perfumes are added to create a pleasant olfactory atmosphere.

The combustion process

Now that we know the basic components of a candle, let's explore how it burns.

When you light a candle wick, it begins to burn at one end. Here's what happens next:

1. The burning wick : The flame of the wick quickly heats the wax surrounding it. This heat melts the wax and turns it into a liquid.

2. Capillarity : The wick acts like a sort of lamp wick. The heat rises by capillarity, that is to say the melted wax is sucked by the wick to the upper part, where it evaporates.

3. Vaporization : As the wax evaporates, it turns into a gas and reacts with oxygen in the air. This creates a chemical reaction that produces heat and light, forming the flame we see.

What happens in a candle

Now that we know how a candle burns, let's dive a little deeper into the details of what's going on inside.

1. Combustion Zone : The area around the wick is the combustion zone. This is where there is enough heat to melt the wax and vaporize it, creating a flame.

2. Main Flame : The flame we see is the hottest part of the candle. It can reach temperatures of up to 1400 degrees Celsius (2500 degrees Fahrenheit)!

3. Internal Flame : Just below the main flame, there is a small, pale blue internal flame. This zone is rich in oxygen and is where the combustion reaction occurs most intensely.

4. Outer Flame : Around the inner flame, there is a yellow-orange outer zone. This part is slightly cooler than the main flame, which is why it appears different in color.

Understanding the burning process of a candle gives us a new appreciation for these small sources of light. The next time you light a candle, you'll know there's a lot more science and magic hidden behind that soft, calming light. Enjoy the ambiance it creates, while keeping in mind the complex process taking place inside.