Candles are very popular household items that have been in existence for thousands of years. There are different types of candles and each one has a large wealth of history attached to it. Generally, candles were first invented millennia ago by an inventor – or a group of inventors – whose name or names have been lost in the sands of time. They were first made from boiled down tallow or fat obtained from the carcasses of slaughtered cattle and other livestock. However, since the invention of the electric light bulb, a lot of knowledge about candles has been lost.
WHAT ARE CANDLES USED FOR?
Historically, candles serve the function of providing indoor illumination. Their glow not only provides light but also warmth. Additionally, they are used in influencing the atmosphere and ambience of a place. For instance, in candle light dinners, candles are used to provide an air of intimacy between two – well, there are usually two – dinning individuals. Similarly, candles have carved a niche for themselves in the perception of romance, as cultivated by popular media. This is why many marriage proposals tend to feature softly glowing candles along with rose petals, flowers and wine.
Apart from this, candles have also built up a sizable reputation for themselves in the field of aromatherapy. This is largely due to the existence of scented candles, which are basically candles that contain suitable quantities of perfumes or fragrances, which are usually emitted during candle burning. This kind of candles come in a wide variety of fragrances and scent notes from floral to woodsy and spicy. And because of this wide variety, different people with different scent preferences can easily find a scented candle that is perfectly suitable for them.
Asides this, there are so many other uses of candles, some of which surprisingly became quite popular within the last few decades. This is a very fascinating situation, considering the fact that towards the end of the 19th century, candles faced a very real threat of fading out of existence.
This happened because of the invention and mass commercialization of electric light bulbs, which steadily began to fill the role of candles in the provision of indoor illumination. Truth be told, the invention of the electric light bulb did far more than this, it opened doors to new development in the area of indoor illumination and lead to advancements in the usage of electricity.
THE SCIENCE BEHIND THE BURNING OF CANDLES
Candle flames always have to stand straight because…well, there is a whole lot of Physics and Chemistry involved in burning a candle. First, we will examine the chemical aspects.
Candles are made of two important parts, the wick and the wax. And each one of them performs very special functions. First of all, the candle wax serves as the fuel source of the candle, its battery, if you will. Candle wax can be made from different materials (such as tallow or boiled down fat from livestock, beeswax, soy wax, paraffin wax, combination wax or wax which is formed by combining other types of wax in different concentrations and so on). However, each one of these materials serve the special function of supporting burning, even while possessing the ability to melt down to liquid form at high temperatures and solidify to reform blocks of wax at cooler temperatures.
The candle wick, on the other hand is the part of the candle that is lit on fire and melts the wax. The candle wick also absorbs melted liquid wax and uses it to feed and sustain the candle flame.
When a candle is burning efficiently, no fuel is wasted or lost as a result of incomplete combustion and the flame will burn blue (candle flame from incomplete combustion is usually yellow or red). Also, this blue flame burns much hotter than yellow flames and red flames.
However, many people have noticed something unique about candle flames, which is the fact that they always stand straight.
DO CANDLE FLAMES ALWAYS HAVE TO STAND STRAIGHT?
According to science and a whole bunch of scientists, including Michael Faraday, candle flames do indeed always have to stand straight. Not surprisingly, the reason behind this curious fact can only be explained with even more science.
But quite basically, when candles burn, they heat up the air around them and as a rule, hot air rises because it is much thinner and lighter than the rest of the air in the surroundings. However, much cooler air quickly replaces it. This cycle of cooler air replacing hot air is what pushes the flame upwards at all times. Even when you bend a candle or turn it upside down, it keeps trying to burn in an upward direction.
This phenomenon is called “convection current” and it is pretty much invisible, even though it does a lot of work by keeping the flames upright at all times.
Despite this, there are some factors that may make it somewhat difficult for a candle to keep standing straight.
FACTORS THAT CAN AFFECT THE DIRECTION OF A CANDLE FLAME
There are a bunch of factors that could affect the direction of a candle’s flame, but the most prevalent ones have to do with air, in all its precious forms. Candle flames – and any kind of flame for that matter, no matter how small – cannot burn in the absence of air (oxygen, to be precise).
Apart from the inability of a flame to burn in the absence of air, moving air can also constitute its own problems. Moving air – rather, wind – does not have the best reputation with candles.
Candles find it difficult to burn in the presence of strong wind; what usually happens in this case is that the combustion reaction is usually disturbed and left incomplete. When this happens, yellow and red flames are produced in much higher percentages compared to blue flames and more soot is produced. Sometimes, the candles even burn badly, which may result in tunneling (a process in which only the centermost part of the candle burns while the outermost parts melt at a slower rate. Tunneling is bad for the durability of the candle; it reduces the burn time of the candle and leads to wastage of candle wax), flickering of the candle flame and in many cases, it can even put out the candle’s flame.