December 1: Volcano

Volcanism occurs when molten magma (a.k.a. lava) is expelled onto the Earth's surface, also known as extrusive vulcanism (there's a difference in the two words!). A volcano may have a violent, explosive eruption or it may expel its lava via quieter, gentler means. Either way, the landscape around is drastically changed. Lava flow, however, is very good for the planet. It carries nutrients around the crust and mantle, and explains why areas with a lot of volcanic activity are also very fertile. Volcanoes are prevalent around the Pacific in what is known as the Ring of Fire, but they also occur near Iceland and other places, as well as in numerous forms. Some notable volcanoes are Mt. Kilauea, Mt. St. Helens, Mt. Vesuvius (if you know the story of Pompeii in ancient Rome!), Krakatoa, Mt. Fuji, Popocatepetl, Surtsey, and many, many others. Crater Lake in Oregon is the result of Mt. Mazama's collapse nearly 7000 years ago.

December 2: Mendelian Genetics

Gregor Mendel conducted his genetics experiments with pea plants. One such law from his work is the law of independent assortment. A red flower and a white flower produced all red flowers. When these red flowers reproduced, they yielded red and white flowers. Why? The first red was RR, which made it red (dominant), and the first white was ww, which made it white (recessive). Their offspring were all Rw, which yields red because it is the dominant phenotype (trait). The Rw genotypes (genetic traits) mixed to yield RR, Rw, and ww flowers. A similar mechanism is true of hair color and eye color. Another Mendelian law, the law of segregation, in other plants with red and white flowers, both colors are recessive and an rw genotype yields pink flowers! Such simple Mendelian genetics and the later discovered sex-linked traits can show how we end up with certain skin colors, blood types, baldness, diseases, and just about everything else!

December 3: Waterspout

It's a water tornado! It isn't usually as destructive as regular tornadoes but are nonetheless a thing to avoid. Or an amazing spectacle! Whatever floats your boat (no pun intended). They are formed when cumulus clouds touch the water and take up some ocean spray, and are a hazard for both boats and airplanes. Waterspouts have a lesser pressure gradient and lesser winds than true tornadoes.!

ΣF_R=ma_R

ΣF_R is the net force in the radial direction

December 4: Centripetal Force

Centripetal force is the "aiming at the center" force that occurs with circular motion. Consider when you take a ball and string and spin them around above your head. One force keeps the ball going in the circle, and another side force (exerted by the string) pulls the ball inward towards the center: your hand. The net force on the ball keeps it going in this circle. When it is released, it keeps going in the direction it was headed at that point. The string exerts a pull on the ball, and you feel the equal and opposite force on your hand, giving the impression of an outward force. This alleged outward force is called centrifugal force and, despite popular assumption, does not exist.

R.I.P.

December 5: Post-Mortem

Algor mortis is the first stage after death. All brain functions cease and anything in the bladder or bowels is expelled. About half an hour later, blood pools at the lower extremities depending on the position of the body. This is called livor mortis. Rigor mortis, which many are familiar with, is the stiffening of muscles. Beginning about six hours after death, it starts with smaller muscles like eyelids and moves up to big ones like arms and legs at about twelve hours post mortem. This is caused by the cessation of ATP flow to the muscles, so they are stuck in the middle of a contraction. Rigor mortis is complete after about thirty-six hours. Putrefaction and decomposition follow over the weeks and months after death. Soon enough, you're left with naked skeleton!

December 6: Erosion

Solid fragments (soil, rock, etc.) break loose due to some force, usually excessive rainfall, and travel downslope. This is erosion and can be a big problem, especially in areas of sparse vegetation. Loose material drains into bodies of water, increasing the water turbidity, and can be a disaster. Erosion, however, is an important process in the natural formation of the land.

December 7: Stereochemistry

Atom and bond placement is everything in molecule structure. There is a difference between S-alanine and R-alanine (see picture). This has to do with looking at the molecule from the atom or group bonded to the central atom with the lowest atomic number (in this case, an easy hydrogen). Then the other three can be seen in a "steering wheel" view. Follow to the second lowest atomic numbered atom or group and to the next highest one after that. Which direction does it follow, right or left? If right, it is R configuration; left, S configuration. In the case of alanine, keep the hydrogen out front, then look at the NH₂, then the COOH, and finally the H₃C. Have no idea what I'm talking about? Well, look at the picture! (Either that, or do a search. You're on the net if you're reading this. Net search if you want to learn even more!)

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December 8: Black Holes

They have such a strong gravitational pull even light cannot escape. Theoretically, black holes are so massive and dense that the escape velocity (speed necessary to get away) is greater than the speed of light. Curved spacetime is a feature of black holes, in that they distort the very space around them. No matter or information whatsoever and can pass back out of a black hole once it has gone in. General relativity and many other physical theories support the existence of black holes, as well as plenty of astronomical evidence.

December 9: Mitosis

Cells become more cells! When non-mitotic, the somatic cells are in interphase, with their genetic material in its proper place in the nucleus. Prophase is the first stage of mitosis, when the chromosomes split apart into chromatids. Then comes Metaphase, when they line up along an "equator" in the dividing cell. The chromatids split away from each other to opposite ends of the cell during Anaphase. The two ends divide into two different cells in Telophase, the final stage. The chromatids replicate in the daughter cells, so now they are both of the same genetic makeup. Complications in this process can yield "transformed" cells, which oftentimes are cancer cells.

December 10: Ice Age

The Earth drops drastically in temperature and therefore falls into an Ice Age. This results in expansion of the polar ice caps as well as significant landscape effects. Changes in atmospheric composition, Earth's orbit, or continental arrangement may all contribute to these periods. The most recent ice age was the Wisconsin glaciation and ended ten thousand years ago.

December 11: Free Radicals

After a few chemical reactions of some sort, on occasion there is a stray electron. Electrons are usually paired, but not this one. It may resonate here and there but remains alone. Therein lies a potential problem. It is quick to react! It is always hungry for DNA! It is involved with arthritis and other problems. Combustion occurs when the strong double bond in O₂ is broken, yielding free radicals, as O₂ is well-known to actually be a "diradical" molecule, meaning it has two free radicals on it.

December 12: Convection

You know the rules. Heat rises. Cold falls. That's convection for you, and it is quite evident anywhere in a liquid or gaseous environment, whether the atmosphere or a bowl of soup. Convection is the heat transfer in this particular environment. It happens on its own but can be externally initiated by simply stirring your soup and whatnot.

December 13: Amino Acids

Glycine! Alanine! Valine! Methionine! Serine! Tyrosine! Phenylalanine! Asparagine! Arginine! Lysine! Leucine! Isoleucine! Aspartate! Glutamate! Cysteine! Histidine! Proline! Glutamine! Threonine! Tryptophan! Put them together in a nice long chain and you've got yourself a protein!

December 14: The Sun

The Sun is required for all life and other processes on our little planet. It is 1.3 million times the size of Earth, with at least eight other planets orbiting it. The Sun is a Class G star, not the brightest among stars but still pretty bright as far as stars are concerned. The surface area of the Sun is about 6.09 trillion square kilometers! Its surface temperature is a sweltering 5780 K.

December 15: Transpiration

Transpiration is a very common leaf process in which the plant loses water through the stomata. More than 50% of a plant's water is lost this way. The reason for it? Well, sometimes the plant has more water than it needs or can hold, so it releases it. This also cools the plant, so it's just like when we animals sweat.

December 16: Earthquakes

When faults move around, the ground shakes. Sometimes earthquakes can be caused by human activity, but usually they are caused by natural geological movements, such as the flow of magma. For the most part, you don't notice earthquakes because they are really small, but the big ones can cause some serious damage. The Pacific Ring of Fire, like in the case of volcanoes, is a common spot for earthquakes.

December 17: Combustion

Heat can be released in an exothermic reaction known as combustion. This involves a gas and another substance reacting to expel this heat. We're quite familiar with fire, a form of rapid combustion giving off lots of heat and light energy, but there are smaller versions of combustion as well, ones that don't cause such obvious carnage. Oxygen combusting into oxides is especially prevalent.

December 18: Fossilization

Sometimes the remains of ancient organisms dodge being broken down over time and are preserved due to various phenomena, such as the presence of sedimentary materials or anoxic conditions. Either way, this leaves pieces of or whole organisms left in near mint condition for us to dig up or just stumble upon someday to learn about what lived in those days. Oftentimes, all that is left are preserved footprints, but those are still quite valuable bits of information.

December 19: Infrared Radiation

On the electromagnetic spectrum between microwave and visible light, infrared radiation sits between wavelengths 700 nm and 1mm. Infrared absorption and emission in the atmosphere significantly contributes to warming our planet, and it is called the greenhouse effect.

December 20: Humidity

How moist is the air? Rain is likely when the air is at 100% relative humidity. Warmer air can hold more moisture than cooler air, so when the air is at 100% relative humidity at a cold temperature, that same amount of moisture would be a lower percentage in warmer temperature.

December 21: Solstice

December 21 is the winter solstice here in the Northern Hemisphere, and the summer solstice in the Southern Hemisphere. June 21 is the other way around. What is a solstice? Earth is tilted on the axis, so that in some positions, the sun shines more on one hemisphere than the other. This is also why daylight is short in winter and long in the summer. Think of it! Santa Claus lives at the North Pole, yet at Christmas, the Arctic is dark 24 hours each day for a few days before and after the solstice.

December 22: Greenhouse Gases

The greenhouse effect, for the most part (if not entirely, it's arguable), is a naturally occuring process facilitated by a few prevalent gases. Water vapor accounts for more than half of the work, but carbon dioxide, methane, nitrous oxide, and ozone all contribute as well.

December 23: Entropy

Entropy is a function of the state of a system and can be the measure of order or disorder in that system. Generally, the second law of thermodynamics says that natural processes tend to move toward a state of greater disorder. In nature, there is so much randomness and irreversible plunges into disorder. Along with a concept known as universal heat death, in which all matter will have mixed into one big uniform mixture and everything is the same temperature and no heat exchange and therefore no work, entropy could very well mean the end of the universe.

December 24: Parthenogenesis

Parthenogenesis, or "virgin birth", occurs when an unfertilized egg develops into an adult organism just like a fertilized egg would. This is common in gastropods, insects, and other invertebrates, but it is also prevalent in certain fishes, amphibians, and reptiles. There are a lot of ways and reasons this occurs in these organisms. In honeybees, the parthenogenetically produced individuals are male and the sexually produced individuals are female. Parthenogenesis may also serve as an adaptation to adverse habitats, when sexual reproduction alone would not be feasible. Apart from and unlike any of these mechanisms or reasons, the occurrence of a human virgin birth two thousand years ago in Bethlehem resulted from a more divine immaculate conception.
That's the Advent Calendar! Merry Christmas!