Candles work on a fairly simple and ingenious
principle. The elements to sustain fire are concealed
in one convenient package. The fuel is the container made of wax. The catalyst that heats up the fuel is the
wick. Once lit, the wax that is surrounding the
flame melts and is drawn into, and up the super absorbent wick. The closer the wax gets to the flame, the
hotter it becomes. By the time it reaches the flame, it is hot
enough that the wax vaporizes and it is the wax vapor that burns. The oxygen it needs is ever present in the
air. There are several types of waxes used to make
different types of candles. The most popular are; Paraffin, Beeswax, Tallow,
Bayberry, and Soy. Because it is a byproduct of crude oil and
can be manufactured cheaply to have several different melting temperatures, the most commonly
used type candle wax is paraffin. Low melting paraffin has a melting point at
or below 130 degrees Fahrenheit or 54.4 degrees Celsius. Medium melting point paraffin melts at 130
to 145 degrees Fahrenheit or 54.4 to 62.7 degrees Celsius. And high melting point paraffin melts at 145
to 150 degrees Fahrenheit or 62.7 to 65.5 degrees Celsius. The higher the melting point of paraffin,
the harder and longer lasting the candle wax is. Noteworthy to the topic at hand is that almost
all trick candles are paraffin wax candles. So why is it so hard to blow out a trick candle? When you blow out a normal candle, there is
a small ember inside the wick itself that continues to burn for a time. This ember is hot enough to melt the wax,
but not hot enough to ignite the vapor and continue the burning process. This ember eventually cools and the candle
goes out completely. In trick candles, however, they add an ingredient
that ignites at a lower temperature than the paraffin wax. This ingredient is usually a pyrophoric metal. Magnesium is the most commonly used pyrophoric
metal in these trick candles, with the magnesium flakes embedded in the wicks. When you blow out the candle, the ember that
remains is hot enough to light the magnesium (needing only to be around 800 degrees Fahrenheit
or 426.6 degrees Celsius). Thus, when that magnesium burns, it burns
so rapidly and at high enough temperatures that the paraffin wax vaporizes and ignites
and the burning process continues. Now, at this point you might be wondering
why all the magnesium in the wick light doesn’t light off when the trick candle is burning
normally. The answer lies in how quickly the magnesium
burns and how much oxygen is required to allow that process to occur. As the trick candle burns normally, the wick
is cooled by the liquid paraffin wax. The barrier that the wax creates between the
magnesium in the wick and the air also helps to keep the magnesium from lighting. But once the candle is blown out, the wick
is exposed to the ember and more air, and voila! The candle lights back up. Bonus Fact:
• A paraffin candle is easy to put out because only a tiny amount of wax is exposed to heat
and therefore burns. Should an entire pool of liquid paraffin catch
fire, it would be like any other hydrocarbon fire, like motor oil, and be extremely difficult
to put out. The most common firefighting method to put
out a hydrocarbon fire is to layer the burning pool with a blanket of foam, thereby separating
the oxygen in the air from the burning liquid. • The music to Happy Birthday to You was
written down in 1893 by Patty and Mildred J. Hill. Originally with different lyrics and titled
Good Morning to All, it was sung at the start of the school day. Despite that they likely copied the tune from
somewhere else and in turn someone else came up with the modern lyrics a couple decades
later, up until 2015 the song was copyrighted, earning a couple million dollars annually
for Warner/Chappell Music who claimed they held the copyright. However, finally in 2015 a class action lawsuit
against said company was settled for $14 million when Warner/Chappell could not show that they
actually held the copyright for the song, despite that they’d been charging businesses
to use the song to the tune of about $2 million per year, as mentioned. Thus, after well over a century, Happy Birthday
is finally in the public domain. Interestingly here is that before this, Happy
Birthday’s previous copyright status is why at certain restaurants they almost universally
had their own unique version of the song they sing to customers on their birthdays. • Although there are reports of even older
people, the oldest verified person ever was a French woman, Jeanne Calment, who died on
August 4, 1997 at the age of 122 years, 164 days. This is possibly around the oldest any human
could live due to telomeres shortening. In a nutshell, telomeres prevent the strands
of DNA from coming undone and also prevent them from accidentally fusing with neighboring
chromosomes. The issue is that these end caps get shorter
each time the cell divides owing to the fact that the enzymes that duplicate the DNA, with
a little help from short pieces of RNA, cannot do so all the way to the end of a chromosome. So something gets cut off every time a replication
occurs. Telomeres ensure that what is cutoff isn’t
critical information. But the result of this shortening each time
is that telomeres eventually become too short to provide an adequate buffer. For reference, human cells can only be replicated
around forty to seventy times before the telomeres become too short. This leads to the cell no longer being able
to correctly replicate and to cell death. So if you took every cell in your body at
the time you were born and accounted for all the cells they would produce and so on, multiplied
that number by the average time it takes for those cells to die, you get what is known
as the ultimate Hayflick limit- the maximum number of years humans can theoretically live. That would be about 120 years, give or take! (You can learn more about this in our video
Can Lobsters Really Not Die of Old Age?)