Science Village

Thursday, November 24, 2005

Advent Calendar 2005!

December 1: Talc
Talc is a very soft metamorphic mineral (hardness 1) with the formula Mg₃Si₄O₁₀(OH)₂. It has a waxy, pearly luster and looks kind of whitish. It has many common uses, such as rash prevention, lubrication, and paint filler. It has a density of 2.58 to 2.83 grams per cubic centimeters (g/cm³).

December 2: Anterior Cruciate Ligament
The Anterior Cruciate Ligament (or ACL) is one of four major ligaments in the knee, and it connects the back exterior part of the femur to the front interior part of the tibia. It is a frequently damaged part of the knee, responsible for the knee troubles for many aging and/or physically active people, especially football players and skiers. If torn, it'll need to be left to heal on its own, or, if completely torn, it must be either left torn (it's not absolutely necessary but without it, other injuries are more likely) or be surgically reconstructed. There are lots of institutions out there working on improving such procedures.

December 3: Hurricane
Yes, earlier this year I had the "fun" of my namesake hurricane turning poor New Orleans into a giant soup bowl. Hurricane season runs from roughly July to November. They form in tropical ocean waters as a low pressure system that spins round and round (direction depends on whether north or south of equator) with heat and moisture building up and feeding into itself. It's a tropical storm until it's winds get up over 75mph. Then it's a hurricane! The path it follows is dictated, like the direction it spins, by the Coriolis effect, which is different between the northern and southern hemispheres.

December 4: Methanol
Chemical formula CH₃OH, methanol is the simplest alcohol. It is colorless, tasteless, toxic, highly flammable, and has almost no odor. Some kinds of bacteria produce it naturally via anaerobic metabolism. Methanol has been used as a fuel in some areas.

December 5: Boron
The lovely fifth element, next door to carbon and sitting atop aluminum. In its metallic form, boron has a hardness of 9.3 and has been known to be used as imitation diamond. It is a poor conductor at room temperature but a good one at high temperatures. It is an electrophile, since it has an electron deficient p-orbital. It can also transmit infrared light. It has a melting point of 2076º C (3769º F, 2349 K) and a boiling point of 3927º C (7101º F, 4200 K).

December 6: Cedric the Red Eye Tetra
Cedric, star of Issue 5, is a Red Eye Tetra (Moenkhausia sanctaefilomenae). Today marks 18 months since I first brought him home from the aquarium store, and he's still alive! Amazing. Seems to be in good health. He's almost two inches long, which is about the maximum length of Red Eye Tetras. Their lifespan is generally about two years. Cedric is a shiny silver all over with a black stripe over his caudal (tail) fin and, of course, a bright red spot around each eye.

December 7: Pearls
Pearls are made inside oysters and certain other mollusks. They are formed from the mollusk depositing calcium carbonate (CaCO₃) layers, both aragonite and calcite. This mixture plus this stuff called conchiolin that holds it all together forms mother-of-pearl. Pearls are usually white with some tints of various other colors, but sometimes black pearls occur.

December 8: Fructose
Along with glucose and galactose, fructose is a reducing sugar and a monosaccharide (simple sugar). Along with glucose, it makes up sucrose. It occurs naturally in honey and lots of fruits and vegetables. For diabetics, and hypoglycemics, it is a sucrose substitute. Structurally, fructose comes in four different isomers, which, because chemical structure is so important, can make a huge difference in its function. It is a hexose (6-carbon sugar, a pyranose) but most often occurs in a pentose (5-carbon, a furanose) form.

December 9: Tunicates
These are among the invertebrate chordates, meaning they have a spinal cord but do not have an actual back bone. They are also known as urochordates and sea squirts. They live in the ocean and are filter feeders, feeding via input and output siphons. Most are hermaphroditic. Their early development is the same as the rest of us chordates, what with a notochord (primitive spine) and all. In the larval stages, they swim around a lot, but they pretty much stay perched in one spot when they are adult.

December 17: Poinsettia
Aside from Hortense's lovely, enduring Holly, another very nice Christmas plant is the Poinsettia (Euphorbia pulcherrima). It's got nice big, usually red leaves and small flowers in the middle of those leafy branches. In their native habitat of Central America, Poinsettia can grow as tall as 16 feet! From October to December, any nighttime light would apparently cripple the plant, making it unable to flower. Poinsettia is non-toxic, despite an old common belief.

December 18: Enamel
It is the hardest substance in the body. It makes up teeth, along with dentin, cementum, and dental pulp. Enamel is the outer, thickest, by far most mineralized part. Exact thickness varies.

December 19: Thunderstorm
Although around here they're mostly in the summer time, thunderstorms can occur anywhere in the world at any time of year. If you've got lower atmospheric moisture plus a drastic drop in temperature higher up plus cold front mechanical convergence, then CRASH! You've got yourself a run of the mill thunderstorm!

December 20: Common Cold
Not to be confused with the similar yet more severe influenza, the common cold is a viral upper respiratory illness. The virus likes to spread around via sneezes and coughs to attack more hapless victims, more victims to have to suffer from painful phlegm and earache and sneezing and congestion and all the other nasty stuff it does. And, despite popular misconception, it can strike any season. So watch out!

December 21: Tropic of Capricorn
It is on this day, December 21, the Winter Solstice (or Summer Solstice in the southern hemisphere) the sun's rays are strongest over the Tropic of Capricorn, at 23 degrees South. This is the southernmost latitude of the world region known as "tropical".

December 22: Twins
Twins come in the identical and fraternal kinds. Identical twins were originally one egg that, after fertilization, split into two genetically identical eggs, thus forming the genetically identical twins. They are always the same sex, same blood type, etc. Conjoined twins are always identical twins, ones that just didn't fully separate from one another! Fraternal twins, on the other hand, occur when two eggs are ovulated at the same time and are both fertilized. Since they are genetically different, they are just as different as any other siblings and may be different sexes.

0 K
December 23: Absolute Zero
It all stops here. At absolute zero, Zero Kelvin, minus 273º Celsius, all gases have liquefied. At absolute zero, all metabolic processes cease. At absolute zero, there is no heat. When there is no heat, nothing happens. Everything stops.

December 24: Star of Bethlehem
SciVille's Aerial Watchman has spent years looking at star charts and reading up on old astronomy, trying so hard to learn what the miraculous Star of Bethlehem was like. He's found some theories including that the Star was actually a supernova or a comet. Another common theory is that all of the planets aligned just right to form the Star of David, thus pointing out to the Magi that the newborn King of the Jews was there. Such a phenomenon apparently could only occur once in over 40 million years!

Well, that's the advent calendar. Have a very Merry Christmas!!!

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© 2004-2007 Katrina G. Moncure unless otherwise stated. Do not copy anything on this site without my permission. All rights reserved.

	December 1: Talc Talc is a very soft metamorphic mineral (hardness 1) with the formula Mg₃Si₄O₁₀(OH)₂. It has a waxy, pearly luster and looks kind of whitish. It has many common uses, such as rash prevention, lubrication, and paint filler. It has a density of 2.58 to 2.83 grams per cubic centimeters (g/cm³).
	December 2: Anterior Cruciate Ligament The Anterior Cruciate Ligament (or ACL) is one of four major ligaments in the knee, and it connects the back exterior part of the femur to the front interior part of the tibia. It is a frequently damaged part of the knee, responsible for the knee troubles for many aging and/or physically active people, especially football players and skiers. If torn, it'll need to be left to heal on its own, or, if completely torn, it must be either left torn (it's not absolutely necessary but without it, other injuries are more likely) or be surgically reconstructed. There are lots of institutions out there working on improving such procedures.
	December 3: Hurricane Yes, earlier this year I had the "fun" of my namesake hurricane turning poor New Orleans into a giant soup bowl. Hurricane season runs from roughly July to November. They form in tropical ocean waters as a low pressure system that spins round and round (direction depends on whether north or south of equator) with heat and moisture building up and feeding into itself. It's a tropical storm until it's winds get up over 75mph. Then it's a hurricane! The path it follows is dictated, like the direction it spins, by the Coriolis effect, which is different between the northern and southern hemispheres.
	December 4: Methanol Chemical formula CH₃OH, methanol is the simplest alcohol. It is colorless, tasteless, toxic, highly flammable, and has almost no odor. Some kinds of bacteria produce it naturally via anaerobic metabolism. Methanol has been used as a fuel in some areas.
	December 5: Boron The lovely fifth element, next door to carbon and sitting atop aluminum. In its metallic form, boron has a hardness of 9.3 and has been known to be used as imitation diamond. It is a poor conductor at room temperature but a good one at high temperatures. It is an electrophile, since it has an electron deficient p-orbital. It can also transmit infrared light. It has a melting point of 2076º C (3769º F, 2349 K) and a boiling point of 3927º C (7101º F, 4200 K).
	December 6: Cedric the Red Eye Tetra Cedric, star of Issue 5, is a Red Eye Tetra (Moenkhausia sanctaefilomenae). Today marks 18 months since I first brought him home from the aquarium store, and he's still alive! Amazing. Seems to be in good health. He's almost two inches long, which is about the maximum length of Red Eye Tetras. Their lifespan is generally about two years. Cedric is a shiny silver all over with a black stripe over his caudal (tail) fin and, of course, a bright red spot around each eye.
	December 7: Pearls Pearls are made inside oysters and certain other mollusks. They are formed from the mollusk depositing calcium carbonate (CaCO₃) layers, both aragonite and calcite. This mixture plus this stuff called conchiolin that holds it all together forms mother-of-pearl. Pearls are usually white with some tints of various other colors, but sometimes black pearls occur.
	December 8: Fructose Along with glucose and galactose, fructose is a reducing sugar and a monosaccharide (simple sugar). Along with glucose, it makes up sucrose. It occurs naturally in honey and lots of fruits and vegetables. For diabetics, and hypoglycemics, it is a sucrose substitute. Structurally, fructose comes in four different isomers, which, because chemical structure is so important, can make a huge difference in its function. It is a hexose (6-carbon sugar, a pyranose) but most often occurs in a pentose (5-carbon, a furanose) form.
	December 9: Tunicates These are among the invertebrate chordates, meaning they have a spinal cord but do not have an actual back bone. They are also known as urochordates and sea squirts. They live in the ocean and are filter feeders, feeding via input and output siphons. Most are hermaphroditic. Their early development is the same as the rest of us chordates, what with a notochord (primitive spine) and all. In the larval stages, they swim around a lot, but they pretty much stay perched in one spot when they are adult.
	December 17: Poinsettia Aside from Hortense's lovely, enduring Holly, another very nice Christmas plant is the Poinsettia (Euphorbia pulcherrima). It's got nice big, usually red leaves and small flowers in the middle of those leafy branches. In their native habitat of Central America, Poinsettia can grow as tall as 16 feet! From October to December, any nighttime light would apparently cripple the plant, making it unable to flower. Poinsettia is non-toxic, despite an old common belief.
	December 18: Enamel It is the hardest substance in the body. It makes up teeth, along with dentin, cementum, and dental pulp. Enamel is the outer, thickest, by far most mineralized part. Exact thickness varies.
	December 19: Thunderstorm Although around here they're mostly in the summer time, thunderstorms can occur anywhere in the world at any time of year. If you've got lower atmospheric moisture plus a drastic drop in temperature higher up plus cold front mechanical convergence, then CRASH! You've got yourself a run of the mill thunderstorm!
	December 20: Common Cold Not to be confused with the similar yet more severe influenza, the common cold is a viral upper respiratory illness. The virus likes to spread around via sneezes and coughs to attack more hapless victims, more victims to have to suffer from painful phlegm and earache and sneezing and congestion and all the other nasty stuff it does. And, despite popular misconception, it can strike any season. So watch out!
	December 21: Tropic of Capricorn It is on this day, December 21, the Winter Solstice (or Summer Solstice in the southern hemisphere) the sun's rays are strongest over the Tropic of Capricorn, at 23 degrees South. This is the southernmost latitude of the world region known as "tropical".
	December 22: Twins Twins come in the identical and fraternal kinds. Identical twins were originally one egg that, after fertilization, split into two genetically identical eggs, thus forming the genetically identical twins. They are always the same sex, same blood type, etc. Conjoined twins are always identical twins, ones that just didn't fully separate from one another! Fraternal twins, on the other hand, occur when two eggs are ovulated at the same time and are both fertilized. Since they are genetically different, they are just as different as any other siblings and may be different sexes.
0 K	December 23: Absolute Zero It all stops here. At absolute zero, Zero Kelvin, minus 273º Celsius, all gases have liquefied. At absolute zero, all metabolic processes cease. At absolute zero, there is no heat. When there is no heat, nothing happens. Everything stops.
	December 24: Star of Bethlehem SciVille's Aerial Watchman has spent years looking at star charts and reading up on old astronomy, trying so hard to learn what the miraculous Star of Bethlehem was like. He's found some theories including that the Star was actually a supernova or a comet. Another common theory is that all of the planets aligned just right to form the Star of David, thus pointing out to the Magi that the newborn King of the Jews was there. Such a phenomenon apparently could only occur once in over 40 million years! Well, that's the advent calendar. Have a very Merry Christmas!!!