What is a Mole?

A mole is a universal unit used to measure the amount of a certain chemical. Using grams or absolute numbers of atoms/molecules/ions would be way too confusing. Thus, a mole makes it easier to know how much of a certain chemical there is. The mole today is widely credited to the discovery of Avogadro's number, the number of particles in one mole of any substance. Italian physicist, Amedeo Avogadro, was a lawyer, but later got interested in physics and became a scientist. Avogadro was the first person to propose the idea of molecules. He based much his work on the earlier discovery by Joseph Gay-Lussac that gases combine with each other in simple, whole-number ratios of volumes. For example, one liter of oxygen combines with two liters of hydrogen to make two liters of water vapor. Avogadro argued that this discovery could be proved if it was assumed one liter of gas contained the same amount of particles as any other liter of gas. The next question that arose was, "Then how many particles are in one liter of gas?" Avogadro never devoted significant time to answering this question. In 1865, for example, the German physicist J. Loschmidt estimated the number of molecules in a liter of gas to be 2.7 × 10^22. The accepted value today is 6.02 x 10^23.  

As stated earlier, moles are important to chemistry because they provide a means for measuring the amounts of a certain chemical in a logical and universal manner. In a chemical reaction, moles can be used to determine the amount of a certain chemical needed or the amount that will be produced. There is 1 mole of atoms in the atomic mass of an element when that mass is expressed in grams. Given the mass of a an element in grams, division by the molar mass of the element to get the total moles. Given the particles of an element, it takes division by Avogadro's number to get the amount of moles.

Information collected from the following sources:
http://www.scientificamerican.com/article.cfm?id=how-was-avogadros-number 
http://science.jrank.org/pages/697/Avogadro-s-Number.html 
http://web.vu.union.edu/~stodolan/mole.html 
http://www.chemistry.co.nz/avogadro.htm

Coupled Biogeochemical Cycles

Biogeochemical cycles are the movements of matter between Earth's different spheres. The statement that these cycles implies that they are all interconnected. Whether that may be the water, nitrogen or oxygen cycle, each is affected by a change or altering of the others. At the time the article, "Earth's Biogeochemical Cycles, Once in Concert, Falling Out of Sync" was written, scientists were preparing to convene at a meeting in which they would discuss coupled biogeochemical cycles (CBC) funding. "CBC is an emerging scientific discipline that looks at how Earth's biogeochemical cycles interact." Many scientists and researchers are beginning to look at the coupled cycles rather than sticking to them separately as their own entities. A prime example of this is the dead zone idea. Nitrogen-based fertilizers that are used in the cornfields of Iowa seep into the Mississipi River, and are carried down to the Gulf of Mexico. There, the nitrogen stimulates an algae growth. Upon the algae dieing, their decomposition consumes oxygen making an area of water roughly the size of New Jersey inhospitable to animal life. A simple action that began in the nitrogen cycle could end up having a drastic effect in the oxygen cycle. All the biogeochemical cycles take place in the many environments of this world. Even the smallest changes in atmospheric composition or fertilizers used could end up affecting the other cycles and the environment in the end. There is so much more to learn about the cycles and their relations with each other than there would be to learn from them separately.

The cycles are like a machine; when one piece starts running off course, the other parts cant function properly making the machine ineffective.

The Effects of Strain on an Atomic Level

I have just read a very interesting article about researchers at North Carolina University and their current discoveries. These researches have provided some of the first trials and data from testing the effects of putting strain on certain atoms and their connected bonds.

http://www.sciencedaily.com/releases/2010/10/101007171413.htm

1. The types of bonds in certain materials are directly related to the materials' properties. Some of these properties include hardness and transparency.

2. The application of strain on the bonds in any one direction can increase the chemical reactivity of the bonds, and influence the structure in various ways.

3. Manufactures, who build many silicon-based devices, have begun to alter the silicon crystals during bond formation with the application of stress. This will allow manufacturers to be more selective during the manufacturing process, and to create more suitable products.

4. The effects of the application of stress on bond formation haven't been fully researched and documented. The researchers at North Carolina University are some of the first in putting light on this topic. After there is more data and information available, humans will have a better understanding of the bond formation process and control over it.

The structure of silicon crystals.

Alloys, or Time to Allay The Unkowns

A couple classes ago, it became clear that very few people knew anything about alloys. Whats that? Well, this can be attributed to freshman year Honors Biology. Anyways, I've done a little research on alloys and here are my findings.

Alloys are mixtures composed of two or more elements, one of which is a metal. Generally, alloys are made by melting a mixture of various ingredients and allowing them to cool down as a mixture. The properties of the alloys tend to be superior to their component alloys. Thus, the alloys are made to create a more ideal composition to carry on a certain task.

Sterling silver is 92.5% silver (Ag) and 7.5% copper (Cu). This alloy is harder and more durable than the "pure" silver. Yet, since the alloy contains some copper in it, sterling silver is still soft enough to be used in jewelry, tableware and many other items that we use every single day without realizing it.

A commonly known alloy is bronze, composed of 87.5% copper and 12.5% tin. Bronze is harder than copper, yet easier to cast. This is why bronze and other similar alloys are used in coinage.

There are so many alloys that have been created around the world. To highlight a few more, there's several types of steels made of iron, carbon, boron, chromium, manganese, molybdenum, nickel, tungsten and vanadium. Steel is made to have properties like corrosion resistance, hardness, toughness, and ductility (can be made into a thin wire, pliable still). Steel can be used in bicycle frames. Dental amalgam, and alloy of mercury, zinc and silver, is used by dentists to fill cavities in teeth. This alloy is perfect for that task since it hardens while expanding.

Substitutional alloys are made when the atoms of the different components in the mixture are the same size. If the atomic sizes of the atoms are different, the smaller one will fit in between the spaces of the large one. That would be an interstitial alloy, which steels are.

Birds, The Real Tetrachromats

Currently, my honors chemistry class is learned about electromagnetic radiation and electron configuration. For an assignment, we were told to read an article about the vision of birds, and how their eyes contrast with that of humans.

http://www.webexhibits.org/causesofcolor/17B.html

Here's five interesting facts I learned from reading the article:

1. Humans are are trichromats, having photo-pigments with sensitivities at three peak wavelengths. Birds are in fact tetra- or even pentachromats. They can see four or five peak wavelengths, and sometimes, even ultraviolet waves. It was assumed that only insects could see the ultraviolet waves.
2. The eyes of birds are constructed differently than humans, and definately has something to do with the ability of birds to view more wavelengths. In the eyes, birds have a higher proportion of cones to rods. The oil droplets around the cones in birds, filter out certain light (high-energy lower wavelengths) before it reaches the visual pigment.
3. Birds of all kinds depend on their vision to carry out their day to day activities. Whether they are in the sky and need to locate small animals to snatch up, or find seeds amongst a very green floor full of vegetation, ultraviolet vision is beneficial. With this vision, birds can spot traces left by animals. For birds that prey on small animals, they will be able to guess where their food is. For seed-eating bird, seeds will be easier to spot.
4. The location of the eyes on the birds' heads is different in comparison to humans. Birds like hawks and eagle, whom fly very high and require better vision, have five times more cones than humans do. The spacing in between the eyes when greater, gives the birds increased binocular vision and depth perception. This doesn't necessarily affects the color vision of birds, but it improves the overall visual perception birds have of their environment.
5. The level of vision birds have depends on their life styles. Diurnal birds, active in the daytime, tend to have increased ultraviolet sensitivity. While nocturnal birds, active at night, have increased sensitivity in the infrared spectrum. This may be because they have a relatively higher proportion of cones (mentioned in #2) in their eyes.

These graphs show the differences between the vision of birds and humans in regards to their ability to see "x" amount of wavelengths. (-taken from link listed above)

The Periodic Table, Growing by Time

I have just read an article featured on The New York Times website, "The Periodic Table Expands Once Again" written by the Associated Press. It is a very quick but interesting article that I enjoyed.

http://www.nytimes.com/2011/06/09/science/earth/09elements.html?_r=4&ref=chemistry

The periodic table, a diagram featuring all of the existing elements in the world, is always changing. Dr. Moody, 56, thought back to his high school days, when there were only 104 elements listed. Today, there are 118 elements. On average, a new element is added every 2.5 years. As two new elements, temporarily called Element 114 and 116 (made by smashing calcium ions into atoms of plutonium or curium), were officially recognized by the international science community, the issue of naming elements now comes into debate. Dr. Moody, a chemist with the Lawrence Livermore National Laboratory that discovered these new elements, stated that he was yet to discuss any names for the elements with his colleagues. However, it is clear that regardless of the name, they will end in ium. In recent decades, elements have been named after famous scientists. Examples are nobelium and einsteinium (after Alfred Noble and Albert Einstein). Copernicum, added two years ago to the periodic table, was named in honor of astronomer Nicolaus Copernicus.

It is quite possible that Elements 114 and 116 will be named in honor of scientists who contributed to their discoveries. However, there is a chance that Moody and his team might have a little fun with it. When asked about the process of making new elements, he responded with, "It's just basic science...And kind of fun." It is amusing to know that the complex and precise process of crushing atoms to create new ones that exist for only a blink of the eye, is fun.

The Glow-In-The-Dark Millipede

Hello. For my first post, I will be responding to an article about bioluminescence in a species of millipedes. Paul Marek and his team's work provide some of the first pieces of evidence about bioluminescence being used as a warning sign in certain species, based on their data collected in a ground experiment.

http://www.sciencedaily.com/releases/2011/09/110926131805.htm

Here are five facts that I learned from reading this interesting article.

1. Bioluminescence, present in fireflies and glowworms, is the ability to glow in the dark. For these organisms, it is thought that bioluminescence benefits them by attracting mates and even prey, by lighting up the surrounding environment so they can visualize their location and surroundings, and by passing messages along other members of a given species.

2. Motyxia are a genus, family, of cyanide-producing millipedes that live underground. Scientists hypothesized that they ooze toxic cyanide and other repulsive chemicals from small pores, in response to being disturbed. Millipedes that are above ground during the day display colors to anounce their defenses to any potential predators. For the Motyxia that come out during the dark nights, use bioluminescence for the same purpose (or at least it is hypothesized).

3. The rare glow-in-the-dark millipedes can only be found in three places in the world, all of which are in the state of California. To be more specific, The Santa Monica Mountains, the Tehachapi Mountains and the southern Sierra Nevada Mountains.

 4. The biochemical mechanism the millipedes use to activate the glowing, although unidentified thus far, is different than that of fireflies and glowworms. It is believed they have a photoprotein which is activated by calcium and energy-rich compounds in the cell.

 5. These millipedes use their glowing ability to defend themselves from the grasshopper mouse (Onychomys torridus), which are their most common predator. For an experiment conducted involving artificial and real millipedes that either had the glow or not, proves that the bioluminescence feature will successfully fend off the predators.

Mr. Marek's experiment which analyzed the reason for bioluminescence in certain millipedes, was performed validly and followed the scientific method. It is clear that he and his team attempted to answer the problem, why do some millipedes glow in the dark, in other words, for what purpose? His team gathered information about the Motyxia millipedes and other facts about bioluminescence in general. They then hypothesized that the bioluminescence feature was a defense mechanism for the millipedes that protected them from predators. To test their claim, they set up an experiment that tested the effectiveness of the glowing in protecting the millipedes from predators. Exactly 300 fake clay molded millipedes were created, half of which were painted with glow-in-the-dark paint, and the other half paint free. In addition, the team collected live Motyxia millipedes, and covered half of them with paint to cover up their glow. The four types of millipedes were combined and mixed randomly to avoid sampling bias, and strapped to the ground at the Giant Sequoia National Monument in California. The experiment ran one night only, and data was observed the next morning. It turns out that the millipedes who glowed had a higher chance of surviving. "Four times as many non-glowing millipedes showed evidence of attacks compared to their glowing peers. Similarly, in the clay group, non-luminescent models were attacked twice as often than those that emitted the glow." The data collected after evaluation, supported the team's original hypothesis. Lastly, they shared their findings to the science community. Marak and his team conducted their experiment with the scientific method, and can now claim their hypothesis to be valid.