Happy Holidays!!.....Here are some fun facts to share with family about the holidays

Source: Southern Living

With the holidays rapidly approaching, last minute shopping is all around us.  Hysteria at the malls with frantic shoppers trying to wrap up their gift giving expedition.  On top of that weight are the decorations needed for the season.  By now, neighborhoods around the nation are adorned with Christmas lights while Christmas trees are on full display through front windows of houses all around us.  For this year, a couple of fun facts are in order to spread the Christmas cheer.  The two categories will be: Christmas trees and Christmas lights.

How many Christmas Trees are purchased?

Each Christmas season, trees can be spotted on the top of cars as they are transported from the farm to the house to be decorated.  I always have wondered about the number of trees on average which are sold during Christmas.  Therefore, I decided to search Google with the following question: How many Christmas Trees are sold each year?   The answer is shown below:

Source: Google

According to the National Christmas Tree Association, there are between 25 and 30 million Christmas trees sold each year in the United States.  What was fascinating is the total number of Christmas trees grown in the U.S. each year are 350 million.  The information highlighted in the box above comes from the National Christmas Tree Association's website which has a few more fun facts about Christmas trees shown below:

There are approximately 25-30 million Real Christmas Trees sold in the U.S. every year.

There are close to 350 million Real Christmas Trees currently growing on Christmas Tree farms in the U.S. alone, all planted by farmers.

North American Real Christmas Trees are grown in all 50 states and Canada. Eighty percent (80%) of artificial trees worldwide are manufactured in China, according to the U.S. Commerce Department.

Real Trees are a renewable, recyclable resource. Artificial trees contain non-biodegradable plastics and possible metal toxins such as lead.

There are more than 4,000 local Christmas Tree recycling programs throughout the United States.

For every Real Christmas Tree harvested, 1 to 3 seedlings are planted the following spring.

There are about 350,000 acres in production for growing Christmas Trees in the U.S.; much of it preserving green space.

There are close to 15,000 farms growing Christmas Trees in the U.S., and over 100,000 people are employed full or part-time in the industry.

It can take as many as 15 years to grow a tree of typical height (6 - 7 feet) or as little as 4 years, but the average growing time is 7 years.

The top Christmas Tree producing states are Oregon, North Carolina, Michigan, Pennsylvania, Wisconsin and Washington.

I immediately wondered why there was such a large difference between the amount of Christmas trees planted each year and those that are sold.  Sounds like there are only 1 in 10 trees which actually make the cut to be sold in order to end up in a living room for display with decorations and lights.  The industry requires a significant workforce to support the retail which comes along with the Christmas celebration.  Just take the amount of trees grown to be sold are staggering by itself.



To understand the magnitude of the number of trees which are planted along with the amount that are sold, let's imagine that each tree is stacked on top of one another.  How high would that stack of trees reach? The analysis below will show the answer to that question.  In order to start, an assumption regarding the average height of a Christmas tree needs to be introduced.  For the purpose of this analysis, the assumption will be made that the average height of a Christmas tree is 6 feet tall.



First, the amount of trees which are sold annually in the United States is large.  Therefore, choosing a 'unit' of measurement which will appropriately shed light on the magnitude of the values is essential.  A common unit of measurement for large distances on Earth is the 'mile'.  If Google is consulted with the following question: 'How many feet are in a mile?'  The answer is shown below:

Source: Google

There are 5,280 feet in every mile.  To begin analyzing the values, let's look at the numbers which we are interested in.  Each year, there are between 25 million and 30 million Christmas trees sold in the United States.  That is out of a total of 350 million Christmas trees growing across 15,000 farms.



First, each of the amount of trees sold (and grown) in the United States must be converted to units of miles -- using the assumption that each tree is on average 6 feet tall.  The unit conversion is shown below:

The results above indicate that the range 25-30 million trees sold equal to the distance of 28,409-34,090 miles.  Additionally, the total number of Christmas trees grown annually would equal a total distance of 397,727 miles.  In order to understand the magnitude of these distances, a metric is needed to compare the distances with.  What if we took the total distance of stacked Christmas trees and wrapped the line around a sphere (the Earth)?  How many times could the line of trees circle around the Earth?



We need to determine the total distance around the Earth.  If we consult Google with the following question: What is the circumference of Earth?  The answer is shown below:

Source: Google

One trip around Earth (at the center) is equal to traveling a total distance of 24,901 miles.  The three distances of Christmas trees can be divided by the circumference of the Earth -- 24,901 miles as shown below:

The answers indicate that the amount of Christmas trees sold in the United States each year would stack up to a range of 28-34 thousand miles -- which would equal just over 1.4 trips around the Earth.  Additionally, the total number of Christmas trees grown in the United States would stack up to a distance equal to 16 trips around the Earth.  These numbers really drive home the magnitude of the amount of Christmas trees needed for the Christmas holiday.  Here is a great idea for recycling parts of the Christmas tree -- click here.



How about Christmas light?



In the next section, an analysis will be carried out to highlight the total number of Christmas lights which are purchased each year in the United States.

How about Christmas Light?

On top of all of the Christmas trees which are sold annually and would wrap around the circumference of Earth are Christmas lights -- at the very least to provide the minimum amount of decoration.  In order to wrap a few strands of Christmas lights around a given tree, either one must store Christmas lights in the garage or choose to purchase new strands.  There is nothing wrong with purchasing new lights in a given year.  Especially when the old lights break or strands of bare exposed wire show -- which could easily cause danger when voltage is applied to them (i.e. plugged into the wall socket).  How many strands are sold in the United States each year?



If a Google search is conducted with the question above, the following answer appears below:

Source: Google

According to our search, there are 150 million strands of Christmas lights sold each year in the United States.  If the same analysis from above is used, the first step will be to convert the strands of lights into a distance.  For this, an online store needs to be consulted to find out the distance sold.  The Christmas lights (clear, no color) sold at Target are shown below:

Source: Target

The length of the Christmas lights in the picture above (100 count) is 24.7 feet.  If the total number of strands of Christmas lights is multiplied by the length (in feet) of a single strand, the total distance would be yielded:

The answer indicates that the total number of strands of Christmas lights would add up to a total distance of 701,704 miles in length.    Last, if the total distance of Christmas lights sold is divided by the circumference of the Earth, the total number of trips around Earth will be yielded as shown below:

The total amount of Christmas lights sold in the United States each year would equal traveling around the Earth 28 times.  Wow!  That is an enormous amount of Christmas light sold each year.  The enormous number made me question the total amount of Christmas lights which are sitting in boxes in closets, attics, and garages in American houses across the country.  Additionally, a certain percentage of this enormous amount of purchased Christmas lights must be recycled.



If the Wikipedia page for Christmas Lights is consulted regarding the recycling of Christmas lights, the following information can be found:

Christmas lighting does lead to some extensive recycling issues. Every year, more than 20 million pounds of discarded holiday lights are shipped to Shijiao, China (near Guangzhou), which has been referred to as "the world capital for recycling Christmas lights".[28] The region began importing discarded lights around 1990 in part because of its cheap labor and low environmental standards.[28] As late as 2009, many factories would simply burn the lights to melt the plastic and retrieve the copper wire, releasing toxic fumes into the local environment.[28] A safer technique was then developed that involved chopping the lights into a fine sand-like consistency, mixing it with water and vibrating the slurry on a table causing the different elements to separate out, similar to the process of panning for gold.[28] Everything is recycled: copper, brass, plastic and glass.

More and more cities in the U.S., for example, are setting up sensible alternatives and schemes to recycle Christmas lights, with towns organizing drop-off points for handing in old or discarded lights.[29][30]

Installing holiday lighting may also be a safety hazard when incorrectly connecting several strands of lights, repeatedly using the same extension cords, or using an unsafe ladder during the installation process.

The total amount of Christmas lights (in weight) which are shipped to China each year is around 20 million pounds.   I wonder how much material (copper, brass, plastic, and glass) -- percentages of each are recovered.  And used for what?  The process of recycling is interesting and worth reading about for further information.

Conclusion...

The Christmas holiday is a time of celebration.  At the same time, the holiday is an opportunity for families to gather together and catch up on life.  The fun facts calculated and gathered surrounding the Christmas holiday are perfect to add into a trivia game or dinner conversation.  The analysis above showed that the enormous amount of Christmas trees would add up (stack up to) to enough miles to equal 1.4 times traveling around the Earth.  Further, the total number of Christmas trees planted on farms would equal a distance equivalent to traveling around the Earth 16 times.  That is amazing to say the least.  That is a large amount of wood to recycle or burn.



And what about the Christmas lights which are sold each year in the United States?  The total distance of all of the strands of lights sold in the United States each year would be equivalent to traveling around the Earth 28 times.  My goodness that is quite a large amount of Christmas lights sold each year.  Imagine the total amount of Christmas lights which are sitting in boxes in closets, attics, and garages around the United States.  To add to that, 701,704 miles are purchased each year.  Christmas time is a very popular holiday of the year.  Have a great holiday celebration!!



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How Do LED Christmas Lights Work?

Pre-Merry Christmas!  Christmas is practically upon us.  If you have been outside, then you have undoubtedly noticed that certain houses and buildings have 'Christmas lights' draped on their structures.  A transition is taking place in the 'lighting industry' from a traditional incandescent bulb toward a 'light-emitting diode'.  Light-emitting diode sounds futuristic.  And in some forms appears to be futuristic due to the narrow bandwidth of light -- precise wavelength.  Some people complain that the traditional 'glow' is gone with the transition from 'incandescent lighting.'  I would say to that statement: hold on -- technology is improving at light speed.

Traditional Christmas Lights

As I mentioned above, the traditional "Christmas lights" were a glass bulb and bulky among other difficulties associated with them.  One major hassle associated with setting up Christmas lights was the inspection of each light bulb on a string of lights in order to determine the culprit (faulty light bulb) before lighting the string.  The laborious process was time consuming and resulted in great frustration.  Although, after hanging Christmas lights up, the seasonal glow that is felt upon viewing them is inexplainable and worth all of the trouble.



How is the 'Glow' generated in old Christmas lights?



Traditional Christmas tree lights are incandescent light bulbs.  Incandescent light bulbs have dominated the market over the last century.  Here is a picture of an 'incandescent Christmas light bulb' shown below:

Source: 'The Christmas Lights Emporium'

As you can see, there is a wired that is asymmetrical (wounded irregularly) in winding in the center of the glass bulb.  The operation of the bulb is described as follows:

The incandescent light bulb or lamp is a source of electric light that works by incandescence, which is the emission of light caused by heating the filament. They are made in an extremely wide range of sizes, wattages, and voltages.

As current travels through the wire, heat due to resistance is generated.  Eventually, the heat is given off as light.  There is still heat given off too.  The warm glow produced by the incandescent light bulb remains to be a large challenge for Light-Emitting Diode makers.  Although, the downside of using incandescent light bulbs is the heat loss associated with the operation.  This could be problematic with lights on a Christmas tree.  The heat from the incandescent light bulbs dries the Christmas tree out.  In the extreme case, the heating could cause a fire.



The above explanation was part of the motivation to produce a more efficient light bulb that does not over heat with continued operation over a long period of time.   Despite the move toward greater use of Light-Emitting Diode lights, the traditional incandescent light is still in wide use today.

Light-Emitting Diodes?

Technology has improved greatly with the introduction of the semiconductor.  Other spin-off technologies are numerous (and I do not need to go into them).  Anyways, typically, when the technology is discussed, the usual turn-off of attention is achieved on the part of the listener.



For example, new Christmas lights are made of "light-emitting diodes".  The "wikipedia" contains the following definition of LED:

A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated.[4] When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.

An LED is often small in area (less than 1 mm2) and integrated optical components may be used to shape its radiation pattern.[5]

Appearing as practical electronic components in 1962,[6] the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are still frequently used as transmitting elements in remote-control circuits, such as those in remote controls for a wide variety of consumer electronics. The first visible-light LEDs were also of low intensity and limited to red. Modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.

Early LEDs were often used as indicator lamps for electronic devices, replacing small incandescent bulbs. They were soon packaged into numeric readouts in the form of seven-segment displays and were commonly seen in digital clocks.

Recent developments in LEDs permit them to be used in environmental and task lighting. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Light-emitting diodes are now used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, and lighted wallpaper. As of 2016, LEDs powerful enough for room lighting remain somewhat more expensive, and require more precise current and heat management, than compact fluorescent lamp sources of comparable output. They are, however, significantly more energy efficient and, arguably, have fewer environmental concerns linked to their disposal[citation needed].

As mentioned in the excerpt above, the LED has taken over the world to replace conventional light sources.   One major reason is the large amount of energy saved by operating a LED compared to a traditional light bulb.  Additionally, the LED Christmas light has a more durable coating and therefore is more stable and longer-lasting.



After reading the excerpt above (first paragraph), you might still have an issue with understanding the operation of the LED.  In a recent article 'Compound Interests' titled "The Chemistry Of Lights" a simple explanation is put forth regarding the operation and design of the LED light.  I am a big believer in "not re-inventing the wheel."  Therefore, I love to share good explanations when I come across one.



Here is an excerpt regarding the operation and structure of the "light-emitting diode":

LEDs consist of two layers of semiconducting material. The layers are “doped” with impurities, which is to say that atoms of elements other than those originally in the semiconducting material are mixed in. This doping can create different types of layers: p-type layers and n-type layers. The n-type layer has a surplus of electrons, whereas the p-type layer has an insufficient number of electrons, and as such has what are referred to as electron ‘holes’: positions in atoms where an electron could be, but isn’t.

When a current is applied to the LED, the electrons in the n-type layer and the electron ‘holes’ in the p-type layer are driven to an active layer between the two. When the electrons and electron ‘holes’ combine, energy is released, and this is seen as visible light. While this explains how light is produced, we have to look a little more closely at what’s going on to explain how different colours can be obtained.

The colours obtained from LEDs are determined by the semiconducting materials used. As you can see in the graphic, there’s not just one material used for all of the different colours, but a range of possibilities. By using different materials, and adding different impurities to these materials, we can change the size of the band gap – that is, the size of the energy difference between the n-type layer and the p-type layer. The bigger this band gap, the shorter the wavelength of light produced by the LED. So for a red LED, a relatively small band gap is required. For blue LEDs, a larger band gap is needed.

Simply beautiful!



 What does such a structure look like?



That is a trick question since the title of the blog post is Christmas lights!  Below is a diagram taken from the 'wikipedia' page for 'LED':

Source: Inductiveload 

The image above appears to resemble the traditional Christmas lights that are seen draped on houses and buildings around town.  From the outside, this may be true.  Although, on further inspection of the image above, there is no 'filament' as we saw above in the picture of the incandescent light bulb.



Why not?



According to the two descriptions of the Light-Emitting Diodes above, the structure is slightly different compared to an incandescent light bulb.  Remember terms 'p-n junction' etc?  A structure of an LED was taken from 'wikipedia' for clarity and is shown below:

Source: S-kei

According to the picture above, if the current (in the form of electrons) travels through the 'n-type' material toward the interface of the two types of material 'p-n junction' (in the center at the boundary of blue and yellow), the corresponding 'hole' moves toward the 'p-n junction' from the blue side.  At the boundary layer, the two are combined.  The combination of the electron and the positive 'hole' at the junction corresponds to light emitted.



Furthermore, if the 'p-n junction' is changed (made larger or smaller) the frequency of light (color) is changed too.  Therefore, the light given off at the 'p-n junction' is precise.  As I mentioned above, one downfall of the LED compared to the incandescents light bulb is the lack of 'glow'.  The factor which gives the light a glow is the 'broad spectrum' of wavelengths (mixture of colors).  In an LED, the interface -- i.e., 'p-n junction' is precisely tuned to give a sharp and very well defined frequency.



The above description was off of the site 'Compound Interests' whose design to display information is in the form of a 'poster' like the one shown below:

I chose to expand on the description given in this poster.  The producer of the above infographic did such a great job, that I felt the need to share this with the public at large.  This infographic went out to the science community last week.  Here are some closing thoughts...

Conclusion...

The movement toward LED technology is on the rise.  There are benefits toward using either type of Christmas light.  LED lights give off a very well defined wavelength (or frequency) of light which results in a crisp sharp light.  Whereas the traditional incandescent lights give off the warm 'glow' made up of a few different color components.  Secondly, there is less heat given off with an LED light compared with the incandescent light bulb.  Which results in greater efficiency.  Finally....



As you travel the world during the holidays, hopefully, your viewing of the many different Christmas lights will be enhanced by this blog post.  Try to identify which Christmas lights use LED technology and which use incandescent light technology.  I hope that each and everyone of you have a wonderful and safe Christmas.  Cheers!



Until Next time, Have a great day!