Are Crystals Alive?

Here is a paper I wrote in October of 2018 examining the question: “Are crystals living things?” This seemingly simple question bifurcates into an inconclusive study of the many definitions of life and an intriguing comparison of crystals to living things based off of these definitions. What do you think; are crystals alive? Comment down below or in the forum, and feel free to be as intuitive and/or scientific as you want!


Abram Leyzorek

15 October 2017

Analysis of the Shared Characteristics Between Crystals and Living Things and Study on Definitions of life

Definitions for “life”

Life is defined differently in dictionaries (1) (7), by different scientific fields addressing the subject (2) (3), and by individual scientists studying those fields (9) (10). Entities such as viruses and self replicating proteins fuel a debate concerning whether or not they should be classified as alive or dead. In addition they also provide gray areas, blurring many definitions of life and spawning new ones (2). One conventional and well accepted definition for life requires:

  1. Cellular composition.
  2. Capacity for metabolism.
  3. Capacity for growth and development.
  4. Capacity to reproduce.
  5. Capacity to pass on individual characteristics to offspring through DNA: Heredity.
  6. Tends toward homeostasis.
  7. Capacity to respond to stimuli.
  8. The capacity for adaptation through evolution.

A definition similar to this can be found in many textbooks on biology (4). It will be referred to in this paper as the textbook definition. The aforementioned dictionary definitions (1) (7) will not feature in this paper, as their content and more is provided by the textbook definition and, therefore, reviewing them seems irrelevant to the following purpose: This paper explores whether or not crystals can be considered living under the above definition and others, first by scrutinizing crystals under the textbook definition criteria and then under other definitions. This paper then speculates about the definitions of life and why they are important or not.

Do crystals have cells?

A crystal is defined as a grouping of atoms or molecules arranged in an ordered, repeating pattern. The specific patterns are known as crystal lattices and are defined by the geometric structure of their unit cell. A unit cell is the basic structure that is repeated to form a crystal lattice (5). All crystals must maintain a charge balance; an equal amount of positive and negative charge. Crystals whose external boundaries are described by well developed faces are known as euhedral. However, not all crystal possess this feature. Additionally, crystals may not maintain their structures under changing conditions such as increased or decreased temperature, pressure, etc, but rather will assume different forms, called polymorphs, under certain conditions, while maintaining original elemental composition (6). These characteristics of crystals may demonstrate that they can be defined as living.

1. The structural, functional and biological unit of all organisms.

2. An autonomous self-replicating unit that may exist as functional independent unit of life (as in the case of unicelluar organisms), or as sub-unit in a multicelluar organism (such as in plants and animals) that is specialized into carrying out particular functions towards the cause of the organisms as a whole.

3. A membrane bound structure containing biomolecules such as nucleic acids and polysaccharides.

Definition number one is the most general and will be considered first. Different domains of living creatures have cells organized different ways, i.e. prokaryotic, eukaryotic, and archaeic (11), and have different although similar functions and composition. The same is true even at the taxonomic level of kingdom, e.g. plant cells vs. animal cells (12). If science were to accept another general classification of living creatures, e.g. crystals, it might find that that kingdom also differed in its cellular structure.

The definition of a crystal, as provided above, includes that crystals are made up of cells. They are called unit cells and are the basic building blocks of crystals. They make up the crystal lattice, the structural component. They control the functional aspects of crystals by having interstices, vacancies, and other “defects” that shape the physical properties of crystals and control the movement of atoms in and on crystals. They do this by a process where atoms move from areas of higher atomic concentration to lower atomic concentration called solid state diffusion (13). This process also controls the uptake of elements and compounds into solid solution (15). Since crystals are composed of one of the seven types of unit cells (16), their functioning on a “cellular” level is determined by their unit cells. Unit cells are the basic unit of crystalline solids, so, granted crystals are alive, unit cells are biological units. Thus the first definition of a cell can be satisfied.

In the second definition, the word “autonomous” is used. It is, of course, defined in the biological sense of the word. In that sense, it simply means having an independent existence and governing laws (17). Certainly a unit cell satisfies this definition.

The second term in definition number two is “self-sustaining.” Now, as an article by Astrobiology Magazine entitled, “Defining Life”, (18) points out, no organism can survive by itself; all life needs access to free energy and materials. So, it seems that “self sustaining” must mean that the organism can gather the energy needed to survive from some necessary materials, if they are available. Could a human, for example, self-sustain itself in space? Of course not; the proper environment in which a human could survive is not provided in space. One would not stretch logic to say that every organism needs a specialized environment to survive with proper temperature, weather conditions, food supply, etc. For a crystal to form, it needs its constituent elements close at hand. One example of a favorable environment for a crystal is a solution supersaturated with its constituent element(s). In this environment, crystals will form via nucleation (19) and will impose their structural template onto free atoms of their constituent element and organize them into more crystals (20).

The stipulations of the second definition have all been covered save one: the requirement for cells to be “specialized.” The biological definition for this term is to be set apart for a particular function (21). There are several types of defects in crystals that can enhance certain ones of their functions (13). These “defective” unit cells are set apart from the others and perform a different function; arguably, they are specialized.

At the tertiary definition of a biological cell comes a screen that some crystals cannot pass through. That is the requirement for cells to contain biomolecules and to be wrapped in a membrane. A “biomolecule” is simply an organic (containing carbon) molecule produced by a living creature (22). Obviously this criterion is impossible for a crystal not containing carbon, i.e. inorganic, to meet. But many crystals are organic (23). And therefore all of those, except those solely of carbon, contain biomolecules, if it is granted that crystals are alive. Yet if one grants that crystals are alive, obviously the current scientific conclusion that all life as we know it is carbon-based (25), dissolves. Furthermore, the article referenced (25) goes on to accept the possibility that, although the carbon atom seems the most suited for life, life forms could be based around other elements such silicon or germanium. Why, then, should the definition of life be shackled to carbon?

The next hurdle, however, seems too lofty to leap: the unit cells of these crystals are not surrounded by any membranes. This shortcoming is perhaps excusable because nothing is surrounded by a physical, as opposed to an electrical, membrane at the molecular and atomic levels. Organic cells are enormous in comparison to unit cells. For example, a red blood cell is eight micrometers across (39) and a unit cell of Nickel is about 350 picometers across (40): the red blood cell is about a little under 5000 times larger than a unit cell of nickel, length wise, and even more astronomically tiny by volume. Since membranes, in general, are made up of molecules, how could something the size of a molecule, such as a unit cell, have a membrane? Additionally, if one could grant, for the purposes of argument, that crystals are alive, they would be an entirely different sort of living creature from those biologists are accustomed to. There is no reason to assume that such an entirely different form of life would necessarily depend upon membranes.

In sum, it has been determined that crystals are composed of cells, granted a general definition of the term.

Do crystals have metabolism?

            Crystals are now going to tested by the second criterion: the capacity for metabolism. As above, the discussion will begin with a definition; the Cambridge Dictionary (24) defines metabolism as “the chemical and physical processes by which a living thing uses food for energy and growth.” The previous section on the cellular composition of crystals explained that crystals do grow. Their “food” is comprised of the elements that constitute them. These elements align themselves into the crystal lattice, so the crystal is using their energy to grow. This growth will be covered in further detail in the following section. Crystals, then have a capacity for metabolism.

Can crystals grow and develop?

            Closely related to metabolism is the capacity for growth and development, the third criterion. Anabolism is the specific term for growth (26).  Crystals can grow out of supersaturated solution (20), vapor, and solid mineral deposits (27). The process by which crystals grow has been explained above. As crystals grow, they attain a greater size and their individual compliment of defects and impurities. This is the unequivocal growth and development of a crystal.

Can crystals reproduce?

            The next criterion and perhaps the most important is the capacity to reproduce. Reproduction simply means “the production of offspring by organized bodies” (28). In addition to being able to form naturally by nucleation (19), crystals can form much more quickly by a process called seeding. Seeding involves placing microscopic crystals into a favorable environment for crystallization to accelerate the growth of crystals (29). This is the way in which a crystal reproduces: a piece of a crystal is chipped off the parent and the chip, or seed, carries the information to form new crystals in its unit cells. When it finds a favorable environment abundant with “food”, new crystals, or offspring, are made. This process is asexual, because the offspring are clones of the parent (28).

            The offspring described in the previous paragraph cannot rightly be offspring if they don’t share characteristics of their parent through heredity, the capacity for which is the fifth criterion. The offspring of asexual reproducers are clones of the parent and have essentially identical features. This is, of course, untrue if the offspring grow up in a much different environment than the parent did, and develop differently. The way in which crystals pass their traits to offspring is through a universal code that defines the structure of each crystal. The crystal structure acts as the blue print, like DNA for a new organic organism, a new crystal.

Unfortunately, this process cannot meet the definition of heredity which is complex and restrictive. Heredity is defined as the natural process by which parents pass genes to offspring (30). Genes are chemical patterns on chromosomes that shape the development of offspring (31). Crystals cannot be said to have this characteristic. However, the purpose of genes is to shape the offspring to be like the parent. Although the process described above cannot be called heredity in the strict sense, it clearly accomplishes the same thing. If crystals are a new life form, they have simply found a different way of passing on their characteristics to offspring.

Do crystals maintain homeostasis?

            Every living organism needs a specific needs a specific set of conditions to survive; temperature, pH, salinity, etc must all be within a certain range for a given creature to live. Internal conditions are even more important than external ones. Homeostasis is the process that an organism uses to maintain the same internal conditions despite external changes (32). These processes only work within limits, of course: if a human were plunged into the Sun, homeostasis would not help it.

Crystals have something which could be thought of as homeostasis: an equilibrium crystal shape (ECS). ECS is the shape of a crystal at which it has minimum surface free energy, given a constant volume (33). This is the shape at which a crystal is “happiest.” To demonstrate,  imagine a crystal at its ECS. If one filed off a corner, after a while the crystal would reorganize itself back into the ECS (34). A NASA article acknowledges that crystals can maintain equilibrium (2). These data affirm that crystals perform homeostasis.

Can crystals respond to stimuli?

            Probably the easiest criterion to satisfy, the capacity of life to respond to stimulation, is considered next. Several pieces of information already provided exemplify response to stimulation. The homeostasis of crystals described above constitutes a response to stimulation. Also, liquid crystals can respond to light, heat, and mechanical stress (35). Certain photonic crystals are responsive, as well (36). The aforementioned NASA article (2) also states that crystals can “move” in response to stimuli. Surely this point is affirmed.

Can crystals evolve?

            The final criterion: The capacity to evolve through adaptation. This is, arguably, the characteristic furthest from relevance to the discussion, because it is unclear and hitherto unproven whether bodies normally considered alive today do indeed evolve (3). However, according to the article referenced, there is an enormous collection of data that perhaps the majority of scientists think validates the evolutionary process, as described by a website entitled “Understanding Evolution” (14). Seemingly, though, another individual could consider the facts and develop a different interpretation, or theory. Furthermore, Steven Benner in an article entitled, “Defining Life” (8) describes how fictional characters, such as androids, that humans today would be forced to consider alive, would not be subject to Darwinian evolution.

Benner posited that humans would acknowledge the living status of such hypothetical creatures, based on our “values” concerning what is alive. For example, if an unconventional being such as a cloud were to float one day into a person’s path, and verbally refused to move, displaying sentience, could that person consider the cloud dead? The capacity for evolution does not seem to be one of the characteristics of life familiar to us that people value, such as response to stimulation, reproduction, etc. The reason for this may simply be that evolution is  not observable. It is inconsequential to transient individuals. In fact, most creatures, including some humans, normally only think about reproduction, growth and development, and response to stimuli. The other, less visible ones, such as heredity and cellular composition, are at least observable within a lifetime.

If this weren’t enough, some definitions for life completely exclude the capacity for evolution as a criterion (37). So even if crystals do fail this test, that will not negatively impact their prospects of meeting the criteria of accepted definitions. But, for the purposes of argument, let us assume universal evolution to be true; Do crystals undergo this process?

To answer this question the Cairns-Smith theory will be considered. It stipulates that the first organic life arose from clay crystals that stored and replicated a genome simple enough to have spontaneously arisen (38). The article referenced explores how hypothetical clay crystals might have evolved due to resource scarcity. An ability of crystals to run programs that predict the most abundant resource available in their environment, which would allow crystals to grow faster, might have developed. The research in the paper concludes that it is conceivable for real crystals to have evolved into responsive, sensitive, creatures. This is no real evidence, but a possible proof of concept.

Although this paper has failed to demonstrate that crystals evolve, and therefore failed to completely satisfy the definition it set out to, other definitions that, perhaps rightly, exclude the evolution criterion, have been satisfied.

Cybernetic definition of life

            The textbook definition scrutinized above is not the only proposed definition of life. A cybernetic definition defines life as a network of regulatory mechanisms subordinated to a potential for expansion (9). Crystals certainly possess a network of regulatory mechanisms, and harness these to expand. Unless that extrapolation harbors a misinterpretation of the cybernetic definition, crystals do satisfy it and contain “the essence of life” which, as the authors of the referenced article suggest, the cybernetic definition embodies.

Value based definitions of life

            A previously referenced article mentioned that one way of determining whether or not something is alive based on our values (14). People in general seem to value life for its responsiveness, its growth and development, and its reproduction. The one of those features that isn’t obvious in crystals is responsiveness, although they do possess this characteristic, as argued above. More importantly, though, they don’t respond in ways that humans can naturally interpret. This lack of intuitive understanding is probably a reason why people generally do not consider crystals alive.

At first glance, a coral reef may look inanimate, but with a scientific background one knows that they are alive. Science has provided this viewpoint. It is hard for the unaided human to observe the living properties, such as growth, of a coral reef. Crystals naturally grow very slowly as well. This slow growth of crystals is perhaps another reason that crystals aren’t considered living.

In contrast, a tree seems to grow just quickly enough for people to observe considerable growth in a lifetime. In addition, trees are far more abundant and ubiquitous. Crystals, however, are less obvious and generally paid less attention. Seemingly, for a long time humans in general failed to observe these important characteristics of crystals as a consequence of there inattentiveness and short life spans. Yet, when science began to study crystals, it was too late: people had already developed a system of somewhat arbitrary values that determined in their minds what was alive and what was not. 

In consequence, humans have thought nothing of harvesting and exploiting crystals for their beauty and their great utility in electronics, building, etc. However, this would not be surprising even if humans did consider crystals to be alive. Consider what they have done to creatures in the modern farming and livestock industries. Obviously nothing can be done for the unfortunate case of crystals while those atrocities on more obviously living things (including humans) continue. Of course all living creatures depend on each other for survival, but humans have learned to satisfy their greed for wealth and convenience at an unprecedented level, to the detriment of all life, crystals (perhaps) included.


References

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The Lead and Iron Oxides

Here is a chemistry paper on the lead and iron oxides that I wrote in September of 2018. It provides definitions for the terms “compound” and “oxidation”, as well as giving physical and chemical descriptions of each of the three oxides of lead and the three oxides of iron. I hope you learn something, enjoy, and, if you have a question, ask in the forums!


Lead and Iron are two elements most ancient in their utilization by humans for a vast array of tools and products from swords to ceramics. Quite often, however, they were used in impure forms as oxides. Here a brief explanation of oxidation might prove useful: oxidation is an example of a chemical reaction, which is any interaction between atoms of one or more elements in specific ratios to form a new substance, called a compound (“Definition of Compound”, 2017, pp. 1). The constituents of the compound become chemically bonded and cannot be separated by physical means (“Definition of Compound”, 2017, pp. 1). The resulting compound may have entirely different properties from the constituents (Chemical Reactions, n.d.). One way to form such compounds is by oxidation, the process by which one element, the oxidizer, accepts electrons from another element thus becoming bonded to it (Clark, 2016). Oxidation was named after the gaseous element oxygen, because oxygen is an oxidizing element, as is it highly electronegative, eager to steal electrons. In fact, oxidation was originally understood as in terms of oxygen transfer, rather than the more accurate model of electron transfer (Clark, 2016). Lead and iron are both more electropositive than oxygen, so they will be oxidized in a reaction with oxygen. Depending upon the conditions in which this reaction takes place, it can lead to several different compounds with different properties and uses (Winn, 2004).

Beginning with iron, the first possible compound is a mineral called hematite. Hematite, or Fe2O3, is one of the most common minerals in the world, and is present, at least in small amounts, in many rocks, e.g. sandstone, that have a reddish or brownish coloration, caused by the presence of hematite, although the mineral itself can vary greatly in color, from gray to silver-gray, black to brown and reddish brown (Winn, 2004, pp. 1). In fact, hematite was used until recently to make a dye of the latter color, before cheaper alternatives were developed. It is also responsible for the coloration of Mars, the Red Planet (Winn, 2004, pp. 2). Although it is only paramagnetic under normal conditions, it becomes strongly magnetic when heated, similar to another iron oxide, magnetite. Its hardness ranges from 6-7 on the Mohs Scale, and it may contain small amounts of Titanium. As the principle ore of iron, hematite is mined for the industrial production of iron and is the source of approximately ninety percent of all iron. Fine mineral specimens can be found in several localities, including Minas Garais (Brazil), Cumberland (Cumbria, England), and Ria Marina (island of Elba, Italy). (Friedman, “The Mineral Hematite”, 2018). The chemical reaction that forms hematite looks like this:

4Fe+3O2→2Fe2O3 (Winn, 2004)

That is what happens if there is ample oxygen available, but a different result occurs if the oxygen is less plentiful: Fe3O4, or magnetite. Notice that magnetite has higher iron to oxygen ratio than its cousin, hematite. (Winn, 2004, pp. 4)As referenced before, magnetite earns its name for being a natural magnet and the only mineral with this property. In coloration it is dark gray to black with a hardness slightly greater than hematite at 5.5-6.5. It also differs from its duller cousin in luster, having a metallic luster. Like hematite, though less widely used, it is an important ore of iron. It is of scientific interest due its pronounced magnetic properties. Magnetite can be found almost anywhere around the world, but there are a few noteworthy sources, such as Binn Tal (Wallis, Switzerland), Parachinar (Pakistan), and Cerro Huanaquino (Potosi, Bolivia). (Friedman, “The Mineral Magnetite”, 2018). The chemical reaction that forms magnetite looks like this:

6Fe+4O2→2Fe3O4 (Winn, 2004)

The final oxide of iron is known wüstite. This compound was named after geologist and paleontologist Ewald Wüst (1875-1934) of the University of Kiel in Germany. Wüstite has a hardness of 5-5.5 and occurs mainly in meteorites and anthropogenic slags. (“Wüstite”, 2018). Although its chemical formula is often given as FeO, it breaks the law of definite proportions; the ratio of iron to oxygen ranges between 0.85-0.95/1. Because of this, it is known as a nonstoichiometric compound. This technically allows for an almost infinite number of iron oxides, but all the non-stoichiometric oxides of iron are categorized as wüstite. (Winn, 2004, pp. 9)

Despite this anomaly, most compounds do have distinct stoichiometries, like the lead oxides. first lead oxide is lead monoxide, or PbO. It forms when is heated in the presence of oxygen and can take one of two forms, litharge or massicot, differentiated by their crystal structure. Both are yellowish solids, litharge has a tetragonal crystal structure and massicot has an orthorhombic crystal structure. (“Lead”, 2018, pp. 12). They both have a hardness of 2 on the Mohs scale and have dull, greasy lusters. Litharge has a variety of uses, including in lead acid batteries, glazing pottery, pigments, lead glass, and oil refining. Litharge mines occur on every continent of the world, with an especially high concentration in European countries, such as Sweden, the United Kingdom, and Germany. (“Litharge”, 2018). Massicot mines can be found in many countries around the world, including Madagascar, Namibia, Australia, and Germany (“Massicot”, 2018).

The second lead oxide is known as minium, after the Minius river located in the Northwest of Spain. The chemical formula is Pb3O4, lead tetroxide. Another name for it is red lead, because it can be made into a beautiful read pigment that has been used in paintings since the time of the ancient Romans. Paintings made with minium are called miniatures. (“Red Lead”, n.d.). The hardness of minium is 2.5, and it has a tetragonal crystal structure just like litharge, with a similar luster. Mines are concentrated in Europe but can be found on every continent. (“Minium”, 2018).

The final oxide of lead is plattnerite, otherwise known as lead dioxide (PbO2). It was named in honor of Karl Friederich Plattner (1800-1858) who served as professor of metallurgy and assaying at the Bergakademie of Freiburg in Saxony, Germany, by Karl Wilhelm von Haidinger. It is a brown to black mineral that is commercially produced in a process involving the oxidation of the lead oxide previously discussed, minium, by chlorine (“Lead”, 2018, pp. 13). Plattnerite is used in curing polysulfide rubbers, matches and pyrotechnics, and dyes (“Lead”, 2018, pp. 13). The hardness of plattnerite is 5.5 and it has a dull, metallic luster. The plurality of plattnerite mines are in North America, and of those approximately half are in Mexico and half are in the United States, concentrated in the Western side of the country. (“Plattnerite”, 2018).

These three oxides of iron and three oxides of lead are all very useful and very different from each other. This demonstrates the power of chemical reactions, to take the same two elements in different proportions and create new substances with different properties. However, as was touched on briefly, the chemical composition of a compound is not the sole determining factor of the properties of a substance; other factors, such as crystal structure, also play very important roles, as seen in the two forms of lead monoxide, litharge and massicot (“Lead”, 2018, pp. 12). Regardless of their composition and crystal structure, human beings have used the six oxides discussed above for a long time, some for millennia (“Red Lead”, n.d.), and will probably continue utilizing these useful compounds long into the future.


References

“Chemical Reactions”. (n.d.). Retrieved September 4, 2018, from ric.edu: 

Clark, J. (2016, May 1). Definitions of Oxidation and Reduction. Retrieved September 3, 2018, from chem.lbretexts.org: 

“Definition of Compound”. (2017). Retrieved September 3, 2018, from chemicool.com: 

Friedman, H. (2018). The Mineral Hematite. Retrieved September 3, 2018, from minerals.net: 

Friedman, H. (2018). The Mineral Magnetite. Retrieved September 3, 2018, from minerals.net: 

‘Lead”. (2018). Retrieved September 3, 2018, from brittanica.com: 

“Litharge (Lead(II) Oxide), Lead Monoxide”. (2018). Retrieved September 3, 2018, from reade.com: 

“Litharge”. (2018). (Hudson Institute of Minerology) Retrieved September 3, 2018, from mindat.org: 

“Massicot”. (2018). (Hudson Institute of Minerology) Retrieved September 3, 2018, from mindat.org: 

“Minium”. (2018). (Hudson Institute of Minerology) Retrieved September 3, 2018, from mindat.org: 

“Plattnerite”. (2018). (Hudson Institute of Minerology) Retrieved September 3, 2018, from mindat.org: 

“Red Lead”. (n.d.). Retrieved September 2018, 2018, from webexibits.org:

Winn, J. S. (2004, January 6). Stoichiometry of Iron Oxides. Retrieved September 3, 2018, from dartmouth.edu: 

“Wüstite”. (2018). (Hudson Institute of Minerology) Retrieved September 3, 2018, from mindat.org: 

A Short Exposition of Photosynthesis

Here is a short research paper on photosynthesis, that most wonderful and complex phenomenon that makes life possible. It deserves much deeper treatment that a short, high-school level report, but I hope this will provide a decent starting point on your learning journey. Don’t forget to ask your questions in the forum!


Photosynthesis is the process by which energy from the sun is used to chemically combine carbon dioxide (CO2) with water (H2O) to make oxygen and glucose. Green plants, i.e. plants with chlorophyll, and some other organisms utilize this chemical reaction to make food. Plants are primary producers occupying the lowest trophic level. They support all higher trophic levels and thus their level has the highest biomass. Without photosynthesis, most life on Earth would not exist. (1).

            The majority of photosynthesis in plants takes place in the middle layer of the leaves, or the mesophyll. The cells in the mesophyll are equipped with organelles called chloroplasts, specifically designed for carrying out photosynthesis. Inside the chloroplasts are what resemble stacks of coins. Each coin is called a thylakoid and has a green pigment called chlorophyll in its membrane. The entire stack is a called a granum. The grana are occupy a fluid-filled space called the stroma. (1).

            Photosynthesis is actually a complex series of chemical reactions, some being light-dependent and others being light-independent. The light-dependent reactions take place in the thylakoid membranes where the chlorophyll absorbs light which is converted to adenosine triphosphate (ATP), an energy carrying molecule, and NADPH, an electron carrying molecule. It is here that the oxygen we breathe is created from water as a byproduct and diffuses out through the stomata, tiny pores in the surface layer of leaves letting oxygen diffuse out and carbon dioxide diffuse in. (1).

            Then begin the light-independent reactions that are collectively known as the Calvin cycle. They occur in the stroma and use the ATP and NADPH to fix carbon for use in constructing cells and form three-carbon sugars, glyceraldehyde-3-phosphate, or G3P, molecules,  that link up to make glucose. (1).

            In summary, the heat energy from sunlight ends up stored as chemical energy in the bonds of the sugar molecules that can be metabolized by plants and other organisms. (1). The reaction absorbs heat so it can be described as endothermic. (2).

References


  1. “Intro to Photosynthesis.” (2018). Khan Academy. https://www.khanacademy.org/science/biology/photosynthesis-in-plants/modal/a/intro-to-photosynthesis. Date-accessed: 5/14/2018.

2. Helmenstine, Anne Marie. (2018). “Endothermic Reaction Examples.” ThoughtCo. https://www.thoughtco.com/endothermic-reaction-examples-608179

Superfluidity

Here is a paper I wrote in March of 2018 about another intriguing physical phenomenon: superfluidity. I hope you find it as cool as you would have to get to observe this phenomenon, which is usually close to absolute zero! Please enjoy, and don’t hesitate to comment in the forum if you have any questions. That way more people, including me, can learn from your question!


“Superfluidity” describes a property of liquid matter, i.e. the property of having zero viscosity, or immeasurably low, to be precise (1). This means that if a superfluid were stirred, it would cycle in endless vortices, conserving  one hundred percent of its kinetic energy.  And if a hole were made in the bottom of the vessel, then the superfluid would flow out very quickly compared to other fluids, e.g. honey. The rate of flow of course depends on the size of the hole, so for comparisons of viscosity assume that the holes are the same size. If one fills a cup with honey and then pokes a hole in it, then the honey will eventually flow out, but very slowly.  A superfluid, on the other hand, would flow out the highest possible rate, only limited by the size of the hole.  (3). To understand this an understanding of viscosity is needed. The fundamental principle behind viscosity is friction: the resistance that one object has to moving over another. In the case of liquids, which lack structure, it is the friction between the molecules or atoms of the liquid itself that causes viscosity. (2). In the case of a superfluid, there is no such internal friction due to special molecular or atomic makeup. That is the fundamental definition of a superfluid, but these materials can exhibit many other strange properties. (1). Along with the property of zero viscosity comes lower density and a significant change in specific heat. But is this property of zero viscosity that produces the strangest effects.

                Superfluidity and superconductivity are normally only exhibited at extremely low temperatures.  This is because the particles that condense must always be indistinguishable. The Debroglie wavelengths of indistinguishable particles must have a high degree of overlap. Debroglie wavelength equals Planck’s constant divided my momentum, mass times velocity. Since large particles, e.g. baseballs have high mass, their Debroglie wavelengths will be infinitesimally small, which is it is so unlikely that large particles will exhibit wave-like behavior. For Debroglie wavelengths to overlap, they need to be very long, achieved by cold temperatures, and it helps to have a high packing density of the particles. (8). Cold temperatures are very costly to generate, so this requirement limits the practical applications of superfluidity and superconductivity. Some materials used to make the superconductors are also very expensive, e.g. niobium. (9).

                But, there exist so called “high temperature superconductors” that exhibit superconductivity at a balmy eighty kelvins. The BCS theory does not account for the existence of these, but they will probably prove very useful in the future, as they do exist. One current use of superconductors is in particle accelerators, such as CERN. (10).

                Superfluids also exhibit extremely high thermal conductivity, according to some sources infinitely high (12). Heat is transmitted so quickly that thermal waves are created. This is possible due to the fact that the particles of a superfluid are in the same quantum state, i.e. if one particle moves, they all are moved. Heat is conducted when excited particles bump into each other. If a particle bumps into superfluid particle it will move at the same time as all of the other molecules in the superfluid, transmitting the heat from one side of the superfluid to the other instantly. (11).

                Having no internal friction allows for some spectacular displays, e.g. if a vessel is filled with liquid helium-4 which is then cooled below 2.17 kelvin, condensing into a superfluid, it will flow up the walls of the vessel and out of the vessel. This effect is caused by minor differences in temperature and atmospheric pressure inside and outside the vessel. These tiny differences are enough to move the superfluid against the force of gravity because friction does not hinder its flow. (3).

                A vessel with tiny, molecule-sized holes in the bottom would hold liquid helium-4, but if it were cooled below 2.17 kelvins, then it would immediately begin flowing through those holes, again as a consequence of its immeasurably low viscosity. (3).

                Just a month after the discovery of superfluidity, in 1932, another odd effect was observed accidentally bay British physicist Jack Allen. He had a long, thin tube sticking above a liquid helium bath and packed with fine emery powder. He shined a flashlight on the apparatus and the emery powder absorbed the light, slightly elevating the temperature of the superfluid. As long as the light shone, a fountain of liquid helium emitted from the end of the tube above the bath. The heat creates a back pressure that forces the superfluid helium up. (13).

                As stated above, a superfluid could be used to create perpetual motion. Of course, however, no one is deceived that this means that a surplus energy could be produced and thereby unlimited energy; a superfluid can only conserve the energy that it is given and no more, it does not produce any of its own. However, it is a special property of helium that it never settles into solid state, not even at absolute zero; it always remains a liquid. This is because the helium atoms are so weakly attracted to one another that the slight jiggling caused by the quantum uncertainty principle is enough to keep them apart, at least at standard pressure. (3). It would be naive to think that infinite energy could be harvested from the quantum uncertainty principle; as physicists learn more about quantum mechanics, they will probably learn how no energy created or destroyed.

                Superfluidity was first demonstrated in two studies published in Nature in 1938 by the Brittish duo John Allen and Don Meisner, and independently by Russian physicist Pyotr Kapitza.  Alan and Meisner measured the flow of liquid helium-4 through long, thin tubes and found that it flowed with zero viscosity at temperatures below 2.17 degrees kelvin, almost absolute zero. Kapitza made comparable observations on the flow of liquid helium-4 between two glass discs. He also hypothesized a connection between superfluidity, the resistanceless flow of atoms or molecules, and superconductivity, the resistanceless flow of electrons, which had been discovered some years earlier in 1911 by Dutchman Heike Kamerlingh Onnes. These two concepts were at the frontier of physics back then, and it wasn’t until 1957 that Bardeen, Cooper, and Schriefer (BCS) devised a complete theory to link the phenomena.  (4).

                However, it was very soon after the discovery of superfluidity that an explanation was offered: Bose-Einstein condensation. This is the process whereby  particles known as bosons condense to form a single, quantum state. (4). A boson is a particle whose spin, or intrinsic angular momentum, is zero or an integer. The only other possible class of particle is the fermion, a particle with half-integer spin.  Spin dictates the energy distribution of a particle. Bosons obey Bose-Einstein statistics and fermions obey Fermi-Dirac statistics. Bose-Einstein statistics allows for an unlimited number of particles to occupy a single energy level, unlike fermi-dirac statistics that follow the Pauli exclusion principle, which dictates that no two associated fermions can occupy the same quantum state. (5). Imagine two fermions, say electrons. Let p equal the probability that electron 1 occupies state a and electron 2 occupies state b. Let p1 equal the probability that electron one occupies state a and let p2 equal the probability that electron 2 is in state b. Electrons are indistiguishable, so it is impossible to tell which electron occupies which state. So  p1 and  p2 must be arranged like this:

p=p1p2-p1p2

The above relationship describes a wave function, and if both electrons occupy the same state, a or b, the wave function will vanish. Physicists draw from this the Pauli exclusion principle. The same equation can be used for bosons, except the minus sign must be changed to a plus sign. It is their ability to condense together in unlimited numbers occupying the same energy state that allows bosons to form bose-einstein condensates. (6). But liquid helium-4 atoms are composed of six fermions (two protons, neutrons, and electrons) and no bosons! Liquid helium-4 atoms can form a bose-einstein condensate only because an even number, e.g. 6, of interacting fermions can form a composite boson. This allows liquid helium-4 atoms to condense into the lowest possible energy state and become a superfluid. (4).

                The BCS theory also offers an explanation for superconductivity. An electron moving through a lattice of superconducting material with attract the lattice toward it causing a ripple in the direction of its motion. An electron moving in the opposite with be attracted to this disturbance and the two electrons are coupled together forming what is called a Cooper pair. These cooper pairs can also act like bosons and condense into a state of zero electrical resistance called superconductivity. (7).

                After WW II, large quantities of the light isotope helium-3 became available  because it was part of the manufacturing process of tritium, to be used in hydrogen bombs. It would seem in the light of the information thus far presented that helium-3, having an odd number of fermions (two, protons, electrons, and a neutron), could not condense into a superfluid. But it might be possible, according to the BCS theory, for the helium-3 atoms themselves to form Cooper pairs and thus become a superfluid. The theoretical properties of this hypothetical superfluid helium-3 were explored in the 1960s, before the actual discovery of this superfluid at temperatures below .003 kelvins in 1972. (4).

                The spin quantum number (S) and the orbital quantum number (L) of Cooper pairs characterize two types of angular momentum. Normal BCS superconductors have S=0 and L=0, but superfluid helium-3 has S=1 and L=1. These non-zero quantum numbers cause helium-3 superfluid to break certain basic symmetries of normal liquid state, namely rotational and time reversal symmetries, entailing a non-trivial topology for the Cooper pairs. A variation of the BCS theory was required to understand this, marking the beginning of unconventional superconductivity, but the strange behaviors of unconventional superconductors were only just beginning to be discovered. (4).

                Superfluid helium-3 has two phases, A and B (in the absence of a magnetic field). The B phase exists over a much wider range of temperatures and pressures. It can also exist in many different excited states due to its lack of rotational symmetry, and these states are classified according to the total angular momentum of the cooper pairs (J), with the possibilities J=0,1, or 2. One remarkable feature of the J=2 state of the B phase is its ability to transmit transverse sound waves, something that was previously only thought possible in rigid solids. (4).

                Since the discovery of superfluid helium-3, numerous other unconventional superconductors have been discovered, e.g. cuprates. But only one other superconducting material has been found to have two superfluid phases, namely UPt3. (4).

                Even today, physicists are finding new superfluid properties that defy understanding. The most recent developments in the study of superfluidity involved helium-3 in ultr-light aerogels that was shown to exhibit never before seen phases of superfluids, that are currently being studied. (4).

                Superfluidity was just one of the amazing and counter-intuitive discoveries about quantum mechanics made in the twentieth century, and scientists continue to learn more about it in the twenty-first century. Scientists are a long way from fully understanding the phenomena harnessing its full potential.


References:

  1. Schmitt, Andreas. (2014). “Introduction to Superfluidity.” Springer. https://arxiv.org/pdf/1404.1284.pdf. Date-accessed: 4/18/2018.
  2. “What is viscosity?” (n.d.) Princeton. https://www.princeton.edu/~gasdyn/Research/T-C_Research_Folder/Viscosity_def.html. Date-accessed: 4/18/2018.
  3. Minkel, J. R. (2009). “Strange but True: Superfluid Helium can Climb Walls.” Scientific American. https://www.scientificamerican.com/article/superfluid-can-climb-walls/. Date-accessed: 4/18/2018.
  4. Halperin, William P. (2018). “Eighty Years of Superfluidity.” Nature. https://www.nature.com/articles/d41586-018-00417-7?error=cookies_not_supported&code=4fe886f1-804a-495e-a2a6-830b84b16621#ref-CR10. Date-accessed: 4/18/2018.
  5. Nave, R. (n.d.). “Spin Classification.” HyperPhysics. http://hyperphysics.phy-astr.gsu.edu/hbase/Particles/spinc.html#c3. Date-accessed: 4/18/2018.
  6. Nave, R. (n.d.). “Pauli Exclusion Principle.” Hyperphysics. http://hyperphysics.phy-astr.gsu.edu/hbase/pauli.html#c2. Date-accessed: 4/18/2018.
  7. Nave, R. (n.d.). “Cooper Pairs.” Hyperphysics. http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/coop.html#c1. Date-accessed: 4/18/2018.
  8. Nave, R. (n.d.). “Wave Nature of Electron.” Hyperphysics. http://hyperphysics.phy-astr.gsu.edu/hbase/debrog.html#c3. Date-accessed: 4/18/2018.
  9. Cooley, Lance. Pong, Ian. (2016). “Cost drivers for very high energy p-p collider magnet conductors.” Fermilab. https://indico.cern.ch/event/438866/contributions/1085142/attachments/1257973/1858756/Cost_drivers_for_VHEPP_magnet_conductors-v2.pdf. Date-accessed: 4/19/2018.
  10. “Superconductivity.” (2018). CERN. https://home.cern/about/engineering/superconductivity. Date-accessed: 4/19/2018.
  11. “Properties of fuperfluid.” (n.d.). http://ffden-2.phys.uaf.edu/212_fall2003.web.dir/Rodney_Guritz%20Folder/properties.htm. Date-accessed: 4/19/2018.
  12. “Infinite Thermal Conductivity.” (n.d.). https://superfluidsiiti.weebly.com/index.html. Date-accessed: 4/19/2018.
  13. “Superfluidity II- The Fountain Effect.” (2006). Nature Publishing Group. https://www.nature.com/physics/looking-back/superfluid2/index.html#. Date-accessed: 4/19/2018.

Bell’s Theorem

This is a paper that I wrote in September of 2017 about Bell’s theorem, a very impactful and interesting discovery in physics. I wish I understood more about it. In explaining Bell’s theorem, I also elucidated some basic concepts in physics such as locality and how light works. I apologize for referencing YouTube videos, the faux pas of citation, but, hopefully, you can excuse this singular error and enjoy the content of the paper. Want to talk more about Bell’s theorem? Head on over to the forum.


John Stewart Bell Was born on 28 June 1928, or 6/28/28, in Belfast, Northern Ireland. He died of cerebral hemorrhage at 77 on 1 October 1990 at Belfast. Bell worked for CERN as a particle physicist, but accomplished his most important work in his off time as a hobby: developing his theorem. Bell’s thesis was contradictory to Einstein and was that reality must be nonlocal. This has been supported by many experiments after him, but has been challenged by others, and remains controversial (1). To understand his wonderful and amazing discoveries, one must comprehend also some crucial underlying physics that the following paragraphs first explain.

            Realism as a physical theory is not defined with invariance. It is concerned with the essence of scientific knowledge. Scientific realists believe in the epistemic, having faith in information an observer receives through scientific processes (2). Bell’s theorem contests this.

            Locality states that no information or particles can travel with superluminous speed. Bell’s Theorem contests this also (3).

            Now an explanation for light waves must be provided. It is helpful to first break down the term electromagnetic field. It is a word combing the terms electric field and magnetic field. An  electric field can be imagined as a plane with many vectors on it, each representing a point in space. These are force vectors exerting a force on any charged particle in space, in the direction of the vector and proportional to the length of the vector and the charge of the particle. Now imagine another vector field like the previous one. This represents the magnetic field. Only when a charged particle is moving across it, does it act with force perpendicular to the direction of the particle’s motion and the magnetic field, with a strength proportional to the length of the magnetic field vector, the particle’s charge, and its velocity. Maxwell’s equations describe the interplay between these two fields. When an electric field is circular, i.e. the vectors point in such a way to form a circle, a magnetic field will increase in strength perpendicular to that plane. And conversely, a loop of magnetic field created a change a change in the electric field perpendicular to the plane of the loop. The result of this is electromagnetic radiation, electric and magnetic fields oscillating perpendicular to each other and to the direction of propagation (4).

            The electric and magnetic field components are most easily described separately for mathematical purposes. And it would make the mathematical representation even more convenient if the light represented were horizontally polarized. Polarization refers to the direction that a field is oscillating in. For example, vertical polarization describes a field oscillating up and down (4).

            The electric field component of electromagnetic waves can be mathematically modeled by a cosign function, a variable t for time, a variable a for amplitude, a variable p for phase shift (or where the function is at time t), and a variable f for frequency. That would look like this: a(cos(360ft+p)) (4).

            Every valid wave in a vacuum solves Maxwell’s equations. They are linear equations comprised of combinations of derivatives that mathematically modify the electric and magnetic fields so that they equal zero. Every valid wave in a vacuum gives zero when entered into Maxwell’s equations. Therefore  a valid wave, 0, plus another valid wave, 0, gives yet another valid wave, 0! The third valid wave in physics is called a superposition, or sum, of the original two waves. The superposition of two waves depends for its characteristics on the amplitude and phase shift of the original two vectors. If the original two waves have different phase shift, instead of oscillating up and down or left side to right side, the superposition will oscillate in an ellipse. If the two original vectors have the same amplitude and are ninety degrees out of phase with each other, the superposition will oscillate circularly, in what is known as circular polarization (4).

            Every wave can be described  as a superposition of two oscillating vectors, one on the vertical axis, and the other on the horizontal axis. Although, all waves could also be described with respect to perpendicular diagonal axes. The attitude of the perpendicular axes you choose is known as your choice of basis. Depending on the application, it might be more convenient to choose one basis over another (4).

            What has been presented above is the classical understanding. Most of it translates directly in the quantum world. Classically, the energy of a wave is considered to be the square of the amplitude. Theoretically, this should result in an infinite number of possible energy levels for waves. This seems intuitive, but physicists now know that the energy of a wave is always a discrete multiple of the smallest possible unit of energy. Imagine a staircase. Each step represents an energy level. Every wave is on a specific step and nowhere in between. The height of each step represents the smallest possible increase of decrease in the energy of a wave. This smallest amount is known as Planck’s constant, or h. Every wave has an energy equal to an integer multiple of h times its frequency. This means that there is minimum energy level that a photon can have and if it somehow loses energy at that level, it ceases to exist (4).

            Energy, then, comes in discrete packets of different sizes, but there is a minimum size and all other sizes are a multiple of this minimum one. Now, different frequencies of light only form when the the right size packet is available. When one arrives, they zoom off with it and a light ray is formed. The higher the energy of the packet, the higher the energy of the wave that will take it away. That’s why yhe hotter a fire is, the brighter it is and why its color shifts towards violet as the temperature increases. In normal ambient conditions, only little packets are available, so humans don’t get blinded or cooked to death! These little packets are called quanta, hence quantum mechanics (5).

            An electromagnetic wave at the minimum possible level is known as a photon. The reason photons in themselves can have different energies is because of the third variable in the equation for the energy of an electromagnetic wave: frequency. A different photon can exist at any possible frequency (4).

            In quantum mechanics, the superposition of two perpendicular oscillating vectors to describe any electromagnetic wave must have a new definition. This is because in classical understanding a photon would be a superposition of two vectors with a fractional modulus, and the quantum understanding knows this to be impossible because photons carry the minimum possible energy at their frequency. Classically, the squares of the moduli of the 2 vector components of each wave, tell what percentage of that waves energy can be found in a given direction. However in quantum understanding, a photon must have all of its energy in one direction because its energy cannot be subdivided. So, the amplitudes of the component vectors give the probability that the photon can be found in a certain direction. If the probability is fifty percent for a given direction, half of the time a photon of a certain frequency will be in that direction, and half of the time it will not (4).

            Now the reader is prepared to delve into Bell’s theorem. Proof of Bell’s Theorem involves the use of what are called polarizing filters. A polarizing filter either blocks light from passing through it, or polarizes it in one direction determined by its attitude. What follows is a description of an easy demonstration of Bell’s Theorem and not the actual experiment which is quite complex (5).

            Imagine one vertically polarizing filter. All light photons oscillating in the vertical direction will be let through one hundred percent of the time. Photons oscillating at a forty-five degree angle from vertical will only pass through fifty percent of the time. Now imagine a second philter is placed on top of the first. As the second filter is rotated away from vertical towards ninety degrees away from vertical, less and less light is let through until at ninety degrees away from vertical, light passes through both filters zero percent of the time, provided the filters are perfect. This is because all light that passes through the first filter is vertically polarized, meaning that it has zero percent chance to pass through a horizontally polarized filter (5).

            Now imagine that the second filter is angled at ninety degrees, vertical being zero degrees. Add a third filter in between at forty-five degrees, and more light passes through than before! Twenty five percent of the light passing through the first filter to be exact. This is because the filter in the middle angled at forty-five degrees lets fifty percent of the vertically polarized light through, and that fifty percent becomes polarized at forty-five degrees. Fifty percent of the light polarized at forty-five degrees passes through the third filter at ninety degrees. This seems natural and intuitive (3).

            Many people  have speculated that quantum mechanics isn’t intrinsically probabilistic as shown by how photons pass through a polarizing filter, but that there are some “hidden variables” that man has yet to grasp that describe a fundamental state photons that actually determines whether a photon will pass through a filter or not, not probability (3).

            Bell’s Theorem rests on what happens when a filter at 22.5 degrees, B, is placed on top of a filter at zero degrees, A, and is below a filter on top of the other two at forty-five degrees, C. Based on previous demonstrations, it would be reasonable to expect that seventy-five percent of the vertically polarized light would pass through B and C, because without B, fifty percent of the vertically polarized light passes through, and 22.5 degrees falls halfway between zero and forty-five degrees. Actually, only fifteen percent get blocked at B and another fifteen percent at C (3)!

            To disprove hidden variable theory, first it is necessary to assume it is true. Imagine 100 photons that do have a mysterious hidden variable that answers these following questions. Would a photon pass through A? Would a photon pass through B? Would a photon pass through C? Assume all photons start out being vertically polarized and therefore all pass through A. Fifteen percent get blocked at B, so eighty-five make it through. Another small about, about fifteen percent of eighty-five, get blocked at C. That is much less than the 50 that would get blocked if B weren’t in the middle. So experiments contradict hidden variable theory (3).

            Except, there’s a loophole: if passing through one filter affects how a photon will interact with future filters, then the phenomenon is easily explainable (3).

            But there is a way to circumvent that loophole. It is called the Einstein Podolsky Rosen, or EPR, experiment that was published May 15, 1935 in Physical Review. It uses entangled pairs of photons to measure the probabilities of photons passing through different combinations of filters A, B, and C at the same point in space. Basically, it proves that it is impossible for reality to be locally real (6).

            However, experiments up until 2015 couldn’t prove this unequivocally due to flaws in the equipment used and the experimental setup. But in 2015, this result became unequivocal with a loophole free experiment (3).

References

  1. https://www.youtube.com/watch?v=i1TVZIBj7UA
  2. https://plato.stanford.edu/entries/qt-epr/
  3. https://www.youtube.com/watch?v=MzRCDLre1b4
  4. https://www.youtube.com/watch?v=zcqZHYo7ONs
  5. https://plato.stanford.edu/entries/scientific-realism/

Lecture all about Palm Trees

The monocotyledonous sprout of a coconut palm
The monocotyledonous sprout of a coconut palm
The monocotyledonous sprout of the coconut palm, Cocos nucifera.

Here is a lecture about palm trees that I was required and inspired to make after visiting the city of Jupiter in Florida. It was delivered at my local library, the McClintic Library, on February 23, 2018, almost two years ago. I hope you find it informative and enjoyable.

Jimmy’s Lesson

Here is another poem that I wrote in 10th grade. I wrote it for a recycling-themed competition sponsored by the West Virginia Recycling Coalition, and it won first place ( https://www.theintermountain.com/news/communities/2017/01/recycling-coalition-honors-youth/ ). It is about why recycling is good and a necessary tool to preserve our existence. I have tweaked it slightly, but only to improve the grammar and not to add content. I hope you enjoy it and please let me know what you think!

Jimmy’s Lesson

Gather ’round the homely hearth,
Join me in story and mirth.
Let’s learn to conserve our Earth,
The way she’s done since our birth.

Many modern things cater our comforts:
Cans, crates, signs, scissors, exports and imports.
Everything flows from Mother Earth’s flesh;
This Jimmy understood not, young and fresh.

Awoke he one morn, plunder in his eyes.
He manufactured everything, every size.
Soon only humans littered garbage heaps:
Naught but Jimmy remained on barren steeps.

An idea slept, woke; for joy he leapt!
Recycling! Life began, back it crept.
He realized all resources remain,
for reuse; it starts a reaction chain!

Let’s learn from Jimmy: there’s only so much,
Life may be wrought or reaved by human touch.
Much product is poison if cast away,
If we don’t recycle, we’ll have to pray.

Acacia and Her Ants

Here is a nature poem that I wrote in 10th grade for a poetry contest that turned out to be a possible scam. I have extensively updated and revised it so that only stanzas 2,3,6, and 9 are mostly of the original poem; all the rest I recently added. I was inspired to write this nature poem after reading about the incredible symbiosis between acacia trees and acacia ants. I hope you enjoy it, and let me know what you think!

Acacia and Her Ants

Across the Savannah looms Elephant;
Lumbers towards her, flexing his deadly trunk;
Intends to tear from her trunk, chunk by chunk,
Make her, proud Acacia, a sycophant.

The vigils of her thorns, each a slim, sharp knife,
Her solid, strong branches, her tough woody bark:
All nothing, to Elephant she is stark!
If not for Ants, he’d steal her leaves and life.

Ants are Acacia’s loyal regiment,
Crooked, comely, small; drawn by cause greater:
To guard Acacia, Ants’ Alma Mater.
From her flows food, fueling their sentiment.

“Snap!”, the trunk coils and strikes like a snake,
Sends tremors of torment trem’bling through her,
Arouses Ants’ alacritous nature,
Assembles armies for Acacia’s sake.

Tracking the tremors, Ant’s swarm to attack,
Mandibles mauling hungry gray mountain.
A million minuscule munches’ rain,
Not in vain, drives El’phant, though not slain, back!

Quitting her nectaries, home Ants crawl to,
Ent’ring her homely thorn hollows, now calm.
Full-bellied resting, quelling ev’ry qualm,
Rejuvenates her Cryptozoic crew.

Acacia allures ants and elephants,
The latter by nature, the former by need.
But, unbeknownst to her, both she must feed:
Without Elephant’s worry, she would wean Ants.

Needing nectar, Ants abscond: empty homes,
Ants afar, attract atrocious tenants:
Gracilis ferrugineus supplants.
Acacia, sans Ants, to gruesome gloams roams.

Harmoniously they serve each other,
Ants are children, Acacia is mother.
Wond’rous ’twas how they were brought together,
We’ll only know when free from mortal tether.

An acacia ant resting on a hollow acacia thorn
An acacia ant at the doorway to its thorny yet comfortable home. Photograph by Alexander Wild.

Why the Statue of Liberty is Green

The Statue of Liberty with its iconic green color.
The Statue of Liberty, image retrieved from the National Park Service (4).

The Statue of Liberty is an iconic national monument on Liberty Island that was dedicated on October 28, 1886 (1). Back then, it was not as we see it today; then the exterior was copper colored, because, of course, it was made of copper! But today it is tiffany blue (2) to mint to seafoam green (3), depending upon the lighting (1, see image) (4). This was the result of a series of chemical reactions that took place over the first thirty years after the statue was assembled (5) and provide the reason why the Statue of Liberty is green.

            The first reactions involve a concept called reduction in chemistry. Reduction occurs when an atom that is being oxidized donates electrons to the oxygen atoms. Chemists say that the oxygen atoms have been reduced. (6). They assign an oxidation number to the atom being oxidized that indicates the number of electrons gained or lost by that atom: a positive oxidation number means electrons have been donated and a negative oxidation number means electrons have been gained. Since oxygen is highly electronegative, it is eager to steal electrons. So oxygen tends to take electrons, which reduces its charge. That is the origin of the term “reduction.” Oxygen is more electronegative than most other elements, so in a reaction it is generally the atom that takes electrons and the it is generally the other atoms that give electrons, since they are more electropositive. (7). Since most elements tend to donate electrons to oxygen, the losing of electrons to another element is called “oxidation.” Reduction and oxidation are opposites, but they always go together. Thus, a reaction involving the giving and taking of electrons is called a redox reaction. (6).

            In the first reaction, the copper is oxidized, by oxygen (which is reduced), to form CU2O. This compound is pink or red. Then the copper cation continues to react with oxygen to form copper oxide, 4CuO, which is black to brown. In the first years after Libertas’ figure was erected near New York City, much coal was burned in that city. The resulting air pollution wafted over the Statue of Liberty, bringing with it sulfur. This reacted with the copper to form the compound 4CuS, which is black. Three final compounds form from these initial compounds with the addition of carbon dioxide and hydroxyl ions: CuCO3(OH)(green), Cu3(CO3)2(OH)2 (blue), and Cu4SO4(OH)6(green). (8).

            These three compounds form the iconic blue-green verdigris that encases the Statue of Liberty today. The Statue of Liberty provides a great lesson in chemistry about redox reactions and successive reactions.

References

  1. “Liberty Enlightening the World.” (n.d.).National Park Service. https://www.nps.gov/stli/index.htm. Date-accessed: 4/10/2018
  2. Knapton, Sarah. (2017). “First new shade of blue discovered for 200 years to be turned into Crayola crayon.” See image at end of article. The Telegraph. https://www.telegraph.co.uk/science/2017/05/12/first-new-shade-blue-discovered-200-years-turned-crayola-crayon/. Date-accessed: 4/10/2018.
  3. Morris, Brian. (2015). “50 Shades of Green…and One Shade of Blue.” PsPrint. https://blog.psprint.com/de(signing/50-shades-green-one-shade-blue/. Date-accessed: 4/10/2018.
  4. “Plan Your Visit.” (n.d.). National Park Service. https://www.nps.gov/stli/planyourvisit/index.htm. Date-accessed: 4/10/2018
  5. “Why is the Statue of Liberty Green?” (2018). Wonderopolis. https://wonderopolis.org/wonder/why-is-the-statue-of-liberty-green. Date-accessed: 4/10/2018.
  6. Clarck, Jim. (2016). “Definitions of Oxidation and Reduction.” LibreTexts. https://chem.libretexts.org/Core/Analytical_Chemistry/Electrochemistry/Redox_Chemistry/Definitions_of_Oxidation_and_Reduction. Date-accessed: 4/10/2018.
  7. “Oxidation-Reduction (Redox) Reactions.” (2018). Khan Acandemy. https://www.khanacademy.org/science/chemistry/oxidation-reduction/modal/a/oxidation-reduction-redox-reactions. Date-accessed: 4/10/2018.
  8. Helmenstine, Anne Marie. (2018). “Why is the Statue of Liberty Green?” Thought co. https://www.thoughtco.com/why-statue-of-liberty-is-green-4114936. Date-accessed: 4/10/2018.

The Chemical History of Aluminum

An example of aluminum in use
Aluminum electric line, used for light weight and decent conductivity.

Aluminum is an essential component in a myriad of modern conveniences from airplanes to pop cans, prized for its high strength to weight ratio and resistance to atmospheric corrosion. This silvery-white metal was even more highly valued in the time of Napoleon III, more even than gold. However, this was merely for its extreme rarity rather than for its applications in manufacturing. This only changed when two young chemists, American Charles Martin Hall and Frenchman Paul Héroult, standing on the shoulders of other notable scientists before them, discovered a chemical method to economically extract pure aluminum from its ores. Their method was only the latest in a long line of attempts in the history of aluminum, but it was the first to be commercially utilized on a large scale and is still in use today. (“Commercialization of Aluminum”).

However, for thousands of years aluminum was not even known to exist, despite its use in compounds predating 5000 BC. Ancient Mesopotamians used aluminum-rich clays to craft fine pottery. In addition, aluminum compounds were utilized by Ancient Egyptians and Babylonians as medicines almost 4,000 years ago. And from the ancient world to the medieval period, an aluminum compound, known as alum today, was used to bind dyes to textiles. However, it was not until the eighteenth century that anyone suspected that a metal could be found in these useful compounds. (“Hall-Heroult”).

Aluminum is Christened

Humphry Davy, an English chemist, made the first attempt to extract this metal in 1807. It was made after a long string of successes in isolating pure metals from compounds, such as potassium from potash and sodium from salt, using a method called electrolysis. (Pizzi). Electrolysis is the process of running a direct electrical current from a battery or other source through an ionic solution called an electrolyte using two metal bars as electrodes. The electrons flow from one electrode to the other making one, the cathode, negative and the other, the anode, positive. Positive ions, cations, in the solution are attracted to the cathode and negative ions, anions, are attracted to the anode. When the ions reach their respective electrodes, electron exchange occurs causing a chemical reaction. In this way pure elements can be separated from compounds. For example, if two copper electrodes connected to a power source were inserted into a solution of molten salt, sodium chloride, the negative chloride ions would be attracted to the anode and the positive sodium ions would be attracted to the cathode. At the cathode, the sodium ions would transfer their excess electrons to the cathode and would become neutral. And the same thing would happen to the chlorine ions at the anode, except here there would be a gain of electrons for the chloride ions. The reactions would look like this: (“Electrolysis”).

​At the cathode: Na++ e- → Na

At the Anode: 2Cl- → Cl2 + 2 e-

​Although Davy failed to extract aluminum from alum in this way, he satisfied himself that the metal existed and named it alumium, afterwards rechristening it as aluminum. (Pizzi).

Aluminum is Isolated

​The first sample of aluminum was obtained in 1825 by Danish scientist Hans Christian Oersted who heated a mixture of aluminum chloride and potassium-mercury amalgam under reduced pressure. This caused the mercury to boil away leaving an impure sample of aluminum. (Ashby). This chemical reaction was as follows (Caroll, 5):

AlCl3+3k→Al+3KCl

Using a similar process but with metallic potassium instead of potassium-mercury amalgam, German chemist Friederich Wohler distilled aluminum pieces up to the size of pinheads by 1840. From these samples, he determined the properties of aluminum such as ductility, color, and specific gravity. This made aluminum available, but only at the hefty premium of approximately 545 dollars per pound (1852 dollars). (“The Element Aluminum”).

The Deville Process

Thus, aluminum remained a mere curiosity until 1854, by which time French chemist Henri Saint-Claire Deville had successfully implemented his improvements on the methods of Wohler, namely the substitution of sodium for the more expensive potassium, to produce globules of aluminum the size of marbles using the following method: (“Deville-Castner Process”).

​Deville’s goal in aluminum manufacture was to reduce sodium and aluminum’s double chloride, 2NaClAl2Cl, using heated metallic sodium. The natural first step, then, was to manufacture the double chloride. This process was begun by taking powdered aluminum oxide, or hydrate of alumina (Al2O3+water), and combining it with lamp-black, salt, and charcoal. The resulting mixture was then moistened and processed in a pug mill before being extruded through dies, cut into three-inch cylinders, and dried. These cylinders were then precisely heated in an atmosphere of chlorine gas which causes the desired double chloride to evaporate from which gaseous form it was condensed into a pale-yellow, deliquescent material pungent in odor. The reaction that produced this most important ingredient was as follows: (“Deville-Castner Process”).

2Al2O3+3C2+4NaCl+6Cl2→2(Al2Cl62NaCl)+6CO

Translated into English, the reaction is alumina plus carbon plus salt plus chlorine gas equals double chloride plus carbon dioxide.

Now all that had to be done was the reduction of the double chloride using sodium. To this end, the double chloride was pulverized and mixed with slices of metallic sodium before being heated in a furnace along with cryolite, Na3AlF6, as flux. This resulted in the following reaction: (“Deville-Castner Process”).

2 (Na Cl) Al2Cl6 + 3 Na2 = 8 Na Cl + Al2.

​This simply means that the double chloride chemically reacted with the sodium to produce the desired aluminum and a byproduct of salt. This alone reduced the price to 115 dollars per pound, but the price did not solely depend on the quantities of aluminum that could be obtained.

​The cost of the materials used in aluminum manufacture, a very important one of which was sodium, was a very important factor influencing the price of aluminum. Until 1886 when a man named Hamilton Y. Castner began developing a safe, inexpensive method, sodium production had been very arduous and perilous. Involving electrolysis, the Castner process (completed in 1888) reduced the price of sodium five-fold. Although this development made aluminum more affordable, it was still prohibitive enough to keep aluminum from widespread use. (“Deville-Castner Process”).

The Hall-Heroult Process

​While these achievements represented giant leaps forward in aluminum production, the greatest and yet unsurpassed method was still to come. This discovery was twice made independently by two twenty-two-year-old chemists during the same year that Hamilton Y. Castner developed his sodium production process, 1886. Charles Martin Hall, an American graduate of Oberlin College in Oberlin, Ohio,, worked with Oberlin College professor Frank Fanning Jewett to develop the following process: (“Hall-Heroult”).

First, alumina is dissolved in a vat of molten cryolite at a temperature of 982 degrees Celsius (Ashby), acting as a flux as in the Deville process. Then, it, the electrolyte, is channeled into a cell with a carbon-lined cast-iron shell. Carbon anodes are suspended in the electrolyte and the carbon lining acts as a cathode. An electric current is passed through the cell and the dissolved alumina separates into its constituents, oxygen and aluminum. The molten aluminum sinks to the bottom of the cell and the oxygen remains around the anodes. This involves two half-reactions, reduction of the aluminum at the cathode and oxidation of the oxygen at the anode: (“Extraction of Aluminum”).

Reduction: Al3+  +  3e-       Al

Oxidation: 2O2-  –  4e-       O2

These two half reactions can be combined into one whole reaction which is as follows (“Extraction of Aluminum”):

2Al23+O32-(l)                 4Al(l)   +     3O2(g)

​Paul Louise Toussaint Heroult independently discovered this same process just two months after Charles Martin Hall. He applied for and received a patent for it in France and applied for one in the United States in May of 1886. Although this was before Hall applied for his patent in July, Hall was able to prove that he discovered the method before Heroult made his patent application. Two years later, Hall founded the Pittsburg Reduction Company with financial assistance from six industrialists involved in Pittsburgh’s metallurgical market, including MIT graduate Alfred Hunt. That same year, the price of aluminum plummeted to $4.86. By 1993, the price had dropped to seventy-eight cents per pound. And by the 1930s, it aluminum was valued at just over twenty cents per pound. (“Hall-Heroult”). This remarkable figure was not, however, achieved by Hall and Heroult alone.

Two other notable developments aided in the commercialization of aluminum, namely the dynamo and the Bayer Process. Without the former, none of what Hall and Heroult achieved would have been possible. Invented by Siemens, Hopkinson, and Edison in 1881, it provided the power source necessary for electrolysis. Later, aluminum companies moved to places where abundant hydroelectric power could be found to drive the dynamos. While the dynamo and hydroelectricity made inexpensive electricity abundant, the Bayer process cheapened the raw material for aluminum production, alumina. As the Castner process cheapened sodium, the Bayer process cheapened the production of alumina. (Ashby).

Summary

​Use of aluminum began several millennia ago in pottery and medicine, but it was not until relatively recently that it was discovered. Over the years, better and better methods were devised for aluminum production and the production of ingredients involved in its production. This continued until the price, once greater than that of gold, was reduced sufficiently so that the full industrial potential of aluminum could be realized. This was achieved in large part by the work of Charles Martin Hall and Paul Louise Toussaint Heroult in 1886. (“Hall-Heroult”). These young chemists were heirs to the work of several other notable chemists who made important contributions to the field of aluminum including Humphrey Davy, Hans Christian Oersted, Friedrich Wohler, Henri Saint-Claire Deville, Frank Fanning Jewett, Hamilton Y. Castner, and Karl Joseph Bayer. Standing on the shoulders of these intellectual giants and using new technologies of their day, Hall and Heroult were able to make aluminum available for widespread use.

Works Cited

​”Aluminium and Its Manufacture by the Deville-Castner Process.” (1889). Science, 260-262.

​Ashby, J. (1999). “The Aluminium Legacy: the History of the Metal and its Role in Architecture.” Construction History, 79-90. Retrieved from: https://www-jstor-org.www.libproxy.wvu.edu/stable/pdf/41613796.pdfrefreqid=excelsior%3Af258906f5aaf47b4f874f03071206939                                                                              

“Commercialization of Aluminum.” (2001, November 2). Retrieved November 11, 2018, from acs.org:                                                                                https://www.acs.org/content/dam/acsorg/education/whatischemistry/landmarks/aluminumprocess/commercialization-of-aluminum-commemorative-booklet.pdf

Dr. William F. Caroll, Jr. (2012, April). “From Garbage to Stuff: How we Recycle Plastics.” The Alembic, 39(3), p. 5. Retrieved from                                 https://www4.uwsp.edu/chemistry/acscws/39%20-%203%20April%202012.pdf

Education, T. J.-O. (n.d.). “The Element Aluminum.” (G. Steve, Editor) Retrieved from Jefferson Labs:                                                                                   https://education.jlab.org/itselemental/ele013.html

“16.7: Electrolysis: Using Electricity to Do Chemistry.” (2018, May 4). Retrieved November 11, 2018, from LibreTexts.

“Extraction of Aluminium – Hall (Electrolytic) Cell.” (n.d.). Retrieved November 11, 2018, from mypchem.com:                                                                  http://mypchem.com/myp10/myp10_htm/al_ext.htm

Pizzi, R. A. (2004). “Humphry Davy, Self Made Chemist.” Chemistry Chronicles, 49-51.

“Production of Aluminum: The Hall-Héroult Process.” (2018). Retrieved November 11, 2018, from American Chemical Society:                                  https://www.acs.org/content/acs/en/education/whatischemistry/landmarks/aluminumprocess.html