Thursday, September 5, 2013

Part Two of a Pretty Metal Story

by akshiv, This post originally appeared at Neurons and Quarks.


We had just discovered that steel is way better than cast iron, but it is also hard to make. The Chinese solved this problem quite effectively and this knowledge spread to the rest of the world quite quickly. They figured out how to make wrought iron from pig iron. Pig iron is essentially what iron is like once it had been heated and taken out of the ores from which it originated. After this it went through the process of decarbonisation, actually lowering the carbon content so it starts to resemble steel. Steel is an alloy of carbon and iron just like the more widely available cast iron at the time. The difference is that the carbon content of steel is better suited for making stronger tools and weapons. The problem with this is it took an incredibly long time to get to the right temperatures in open-air furnaces. The Chinese developed the blast furnace, which made this process feasible.
The blast furnace has a few steps involved. Essentially, in the top of your furnace you add the fuel, the pig iron, cast iron, and the flux. The flux is used, as a chemical reactant to purify the product most often this was lime. On the bottom you create a draft of oxygen allowing the combustion of the fuel to take place. As the mixture is heated and product forms it starts to settle at the bottom of the molten stew.

This meant that good steel good be made, but it still took a while with the technology available in the Middle Ages. Steel and iron became corner stones in manufacturing and building around the world being used in everything from buildings, to knives, to cannon balls, to pots.

The industrial revolution took this process and accelerated it tenfold. Henry Bessemer is the father of the process by the same name. It allowed for the rapid conversion of pig iron into steel. It starts with a large crucible through which you allow a draft of air to pass through. Either through the heat of the air or a spark provided the dissolved carbon in the coke is ignited. Allow me to explain. Coke is a fuel with carbon content and very few impurities as a result it can produce high temperatures on combustion, it could be manufactured in the industrial revolution due to the excess of coal. This coke was the fuel incorporated into the pig iron. As the carbon from the coke binds to the pig iron the melting point is raised of it is raised, but because of the heat released upon its combustion the mixture stays molten. This means the speed at which it becomes steel is much quicker. Once the carbon concentration drops enough the draft is cut stopping all combustion reactions. This method allowed the conversation of 25 tonnes of pig iron to steel in UNDER HALF AN HOUR!!

That sort of ends the chapter of iron and steel, moving on to the modern day. Today metallurgy has grown to include numerous metals not just iron, gold, copper, and silver. Modern techniques range from the microscopic like using metallography and crystallography to see the microscopic structure of different alloys to macroscopic like using large pressurized chambers to combine specific quantities. Modern applications of metallurgy are vast because of the adverse conditions in which we place building materials. Metallurgy is no longer tied to metalworking instead it has became a portion of material science, where new alloys are made and tested. My favourite example of this science was in the James Webb Telescope, because the telescope has such massive parts and will be subject to enormous amounts of thermal stress new metals had to be created in order to insure that it would work in outer space.
About this Contributor: I just finished my final year of high school. I love playing ultimate frisbee, skiing and playing the clarinet/guitar. I am happiest when learning random trivia or stargazing. Learning for me is its own reward, whether it is about the quantumly tiny or the cosmologically large.

Tuesday, August 27, 2013

A Pretty Metal Story Part One

by akshiv, This post originally appeared at Neurons and Quarks.

I have been trying to find a way to mould my block of aluminium that Mr. Milne graciously provided; the main issue has been to find a mould not the process of actually melting the aluminium. Anyway this whole business got me thinking about the history of metals and where all of this metallurgy comes from. After all Benjamin Franklin did say: “There never was a good knife made of bad steel.”
So the story really begins about 6,000 BCE when for the first time people were trying to obtain metals simply by heating up ores. This is a process known as smelting and this point it was possible to obtain silver, copper, tin, and lead in this way. It was not very efficient and most of the time surface ores were needed to obtain the metals. There is also the curious case of iron which was the “metal from heaven” often being sold for six times its weight in gold. This is because the only way to get iron at this point was to extract it from meteorite that had fell to the earth. Also a quick note on gold, it was sort of found freely and since it was malleable worked its way into culture. This period of time ends with the beginning of the Bronze Age where it was discovered that combining and tin produced a superior metal (namely Bronze), this was either found in ores or combined during smelting.
The next sort of revolution came with iron. Different places in the world discovered this at different times but the first sort people that seem to hold iron in high regard are the Hittites. Essentially, using the experience they had gotten after years of smelting bronze, humans began to try to smelt iron ores. The technical challenge is in the hot working required to manipulate it.  Not only does the temperature have to be high but the sample cannot be cooled during the process either. This is most likely the reason it took so long to shift from being able to make bronze to making iron.
The Chinese then take this process and improve it ten fold, and once the Industrial revolution hits there is no stopping the growth of metallurgy and the increase availability of new metals and alloys. Stay tuned for part two of the history of metal on Saturday it will be available here.
An example of the kind of meteorite that would have given early civilizations access to iron.
Image is in the public domain, obtained from: http://upload.wikimedia.org/wikipedia/commons/8/8d/TamentitMeteorite.JPG

About this Contributor: I just finished my final year of high school. I love playing ultimate frisbee, skiing and playing the clarinet/guitar. I am happiest when learning random trivia or stargazing. Learning for me is its own reward, whether it is about the quantumly tiny or the cosmologically large.

Monday, August 19, 2013

The key to survival: turtles

by KathyZ, This post originally appeared at Function of a Rubber Duck.

Did you know that turtles could (possibly) save your life?
Scientists have recently been studying western painted turtles, which are known for their amazing ability to freeze solid during the winter and come back to life in the Spring. That’s correct – during the coldest time of the year, this animal’s blood and internal organs are completely solid, and yet, they can recover without any tissue damage once they awake from their “deep slumber.”
Hoping to understand and replicate this power in human beings, scientists at UCLA have paired up with the National Human Genome Research Institute of the US to take a closer look at the turtles’ DNA. With any luck, they may be able to find the key components which can contribute to future innovations in the medical field. Their hopes are that frostbites and hypothermia would no longer cause serious consequences, such as a loss of body appendages. Furthermore, similar developments in medical repair technology can also be used to counter the currently life-threatening heart attacks which are the leading cause of death in several countries around the world. Who could’ve guessed that turtles may be the key in a major medical advance?
One last fact: these turtles can also hold their breath for up to four months during hibernation. If humans could do that, we would consume a way smaller amount of oxygen and expel only a fraction of the CO2  that we do right now… the possibilities are endless.
To conclude, even extremely slow-moving and (literally) cold-blooded animals can make a great difference in our lives, so don’t forget to appreciate Mother Nature and pitch in a hand in preserving our diverse wildlife!


About this contributor: An idoyncratic gr10 student who loves playing the piano, flute and violin and enjoys reading historical fiction and Edgar Allan Poe. She completes jigsaw puzzles in her spare time and aspires to learn Latin as well as publish a children's book in the near future.

Monday, August 12, 2013

The Lunarpolitan Museum of Modern Art

by magdissimo, This post originally appeared at Future Science Leaders blog.

Everything looks better in a museum.  You could take a paper bag, light it on fire, bury it in dirt and then smooth it out again, but as long as it’s under a glass case and tasteful lighting, that paper bag will have an air of sophistication, an air of je-ne-sais-quoi, be the envy of paper bags everywhere.
Of course, in museums housing dinosaur bones, mummy wrappings, delicate clay jars and silver daggers from civilizations gone by, museums ensure the added bonus of your treasure not crumbling away or tarnishing from exposure to air, or in the case of some relics, crushing themselves under their own weight.  But maintenance is hard, requiring vacuum seals, nitrogen baths and protection from certain wavelengths of light.  Paper deteriorates naturally, as does DNA in preserved organisms.
Of course, there are also the dangers that are beyond the calculated abilities of science in the form of break-ins, natural disasters and human conflict.  Thousands of paintings, books and art works were burnt during the Second World War; thousands more were burnt during the Spanish occupation of South America.
Oxidation… high atmospheric pressure… natural disasters… human nature… Now bear with me, readers: I propose we set up a museum… on the moon.
 Bear with me: With no atmosphere to worry about, there is no concern for oxidation or chemical preservation.  With lower gravity, objects are less inclined to collapse on themselves.  Theft and unfavourable weather are of course out of the question, so all we’d need would be a stable structure capable of blocking the much stronger UV rays present on the moon and capable of withstanding small space debris that has a habit of knocking into it on occasion.
Expensive? Perhaps.  Excessive? Debateable.  But as I found while Googling “moon museum”, not entirely original, either.
In 1969, Apollo 12 set down on the moon, the second craft to do so.  While it housed dozens of experiments, three astronauts, one colour tv camera and one mini moon museum, comprising of a ceramic 1.9cm x 1.3 cm plaque with the sketches of six modern artists.  These were John Chamberlain, David Novros, Claes Oldenburg, Robert Rauschenberg, Andy Warhol and the dreamer of the idea himself, Forrest Myers.  It had to be smuggled onto the leg of the space craft, but when the astronauts left, the tiny plaque stayed happily behind.
moonmuseum1
While I couldn’t find any confirmation from astronauts that the plaque still exists, it is pretty neat to think that there is a little slice of art on our beloved pet rock.

About this Contributor: M is a high school student in BC, Canada. She can usually be found playing the accordion or working on one of her many building projects and hopes to one day become an inventor.
 

Thursday, August 8, 2013

Use of Cesium for Wildlife Tracking

by Valzaby, This post originally appeared at Future Science Leaders.


After the devastating earthquake that caused a nuclear disaster at Japan’s Fukushima Daiichi nuclear power plant in March 2011, traces of radiation are now being found in the muscle tissues of Bluefin tuna near off the coast of California. Usually such a discovery would be alarming; however, the levels that are established are too low to harm the fish or the humans consuming the fish. Consequently, the levels of radiation are high enough to allow scientists and conservationists to track and protect this species that is currently being overfished. 
In the spring of 2012, Dan Madigan from Stanford University, along with his colleagues found traces of Cesium isotopes 137 and 134 in Bluefin tuna captured near San Diego. The fish most likely picked up this radiation by feeding on plankton and other small fish near the coast of Japan.  Using the half-life of these radioactive isotopes, they devised a way of studying the tuna fish. Cesium 134 having a half-life of 2.1 years and Cesium 137 one of 30.1 years, allows the scientists to calculate the ratio of the two isotopes in the fish and to see how recently they have migrated to the waters near the US. In essence, the higher the ratio of two isotopes, the more recently the immigrant fish, migrated to the area it was found.
Scientists already knew that the Pacific blue-fin spawn in Japanese waters and spend their first life year foraging [searching for food] in these waters and later either staying put or migrating to Californian waters to fatten up before mating. With the help of the radioactive isotopes, Madigan and company were able to find that the fish aged 1.6 years and younger were migrants from Japan and that the trip for there to the West took them two months. This agreed with what they already knew and validated it.
tuna_news
Tracking Fukushima’s radioisotopes in Fish has potential in being a good tracking technology for the movement of other migratory species in the Pacific Ocean, like whales, turtles, sharks and other fish. Though Cesium 134 levels are soon going to become too little to provide accurate and sufficient information, by correlating Cesium 137 levels with other longer lived and stable isotopes such as Carbon and Nitrogen, Madigan and team created an alternative method for other scientists to use.  Essentially, they found a relationship between Cesium and other radioisotopes that can be easily used in the future. His findings also proved that even the worst of situations and occurrences, can have some positive results.

Sources:
Scientific American Article May 2013 : “Tailing Tuna” by Marissa Fessenden

About this Contributor: Currently a grade 12 high school student who is both ambitious and motivated, but loves to have fun. Interested in human biology, psychology, dramatic soap opera TV shows and fitness through dance, she is in general a very social and open person.

Monday, July 22, 2013

Laser – Light Amplification by Stimulated Emission of Radiation

by akshiv, This post originally appeared at Future Science Leaders.


Lasers are awesome! We use them all the time to do neat things like burn cds/dvds, correct vision, point things out, in printers and even to cut and weld things. These devices just generate beams of light, so how are they so powerful?
There are few reasons this is true. The first lies in the kind of light they produce. Instead of emitting light at all energies and frequencies like a light bulb, a laser only emits on kind of light. This emission is called Monochromatic. This means that the intensity of a single kind (wavelength) of light is extremely high and the rest is really low. The second important factor is the size of the beam, light bulbs radiate light in all directions, leading to diffraction and negative interference, this means that the light is spreads out and starts to interact with it self. Where as in laser a very thin beam of light is produced focusing the energy of the light. Lastly, efficiency plays a large role. Most light bulbs (excluding LEDs) are not nearly as efficient with power as lasers. The reason for this has a lot do with how lasers work so lets get into that.
Flashes of light are bounced around an evacuated tube at first. There is a semi reflective mirror on one side and a reflective mirror on the other side. This allows light to bounce around, while also letting the laser light out. As the flashes of light occur they promote electrons to higher energy levels.
The incident photon (particle of light) adds energy to all of the electrons in the material inside the laser. This is getting a little bit complex but basically electrons normally exist in a “ground state” but they can be promoted to higher energy levels, which are unstable. When there are more atoms in the excited state than in the ground state there is a “population inversion”. Due to quantum effects, one of the electrons will come back to the ground state emitting a photon equal to the energy difference. This is a photon of exactly one energy, instead of all of them. This photon then knocks down all of the other electrons, causing them to emit photon of the same energy also. The reason the light is so intense and efficient is because of this exploitation of quantum effects.
About this contributor: I just finished my final year of high school. I love playing ultimate frisbee, skiing and playing the clarinet/guitar. I am happiest when learning random trivia or stargazing. Learning for me is its own reward, whether it is about the quantumly tiny or the cosmologically large.

Friday, July 19, 2013

Professor Elizabeth H. Blackburn

by AliceY, This post originally appeared at Future Science Leaders.


Elizabeth H. Blackburn was born on 26 November 1948 in Hobart, Tasmania, Australia. Professor Elizabeth H. Blackburn received the Nobel Prize in Physiology or Medicine in 2009 for her discovery of how the enzyme, telomerase replenishes the telomere.
As a child, Elizabeth was fascinated by biology and especially, animals. She was captivated by science books written for young people and re-read the biography of Marie Curie over and over again. When she was in her late teens, she went to Broadland House Girls Grammar School to receive her education. Due to the fact that physics was not offered there, she took physics classes offered in the evenings at the local public high school.
Elizabeth choose biochemistry as her major and graduated with a Biochemistry Honours Degree. She was then offered a position as a master student in The Chair of the Biochemistry Department, Frank Hird’s research laboratory. Afterwards, she proceeded to Cambridge for her Ph.D. student.
Originally planning to do a postdoctoral fellowship with Howard Goodman and Herb Boyer of UCSF, love intervened and she and John Sedat decided to marry. Since John was going to Yale, Elizabeth decided to see if there were opportunities of going into a laboratory in Yale for her postdoctoral training. Joe Gall’s lab at Yale University accepted Elizabeth and she continued her research there.
After finishing her postdoctoral training at Yale University, Elizabeth moved to San Francisco, California with John Gall. She applied for the position of Assistant Professor at various universities including UC Berkeley and once UC Berkeley accepted her, she transferred her funding from University of California San Francisco (UCSF) to her own laboratory at UC Berkeley.
Elizabeth’s research provides insight on how telomeres cap the end of the chromosome and aid in the stability of gene cells. Elizabeth’s early work showed a relationship between the size of telomeres and a chromosome’s ability to reproduce. In 1984, she discovered the enzyme telomerase and after isolating it, found that telomerase synthesizes new telomeres in DNA and also determines the length of the telomeres.  More of her research done afterwards shows that telomeres shrink and cannot reproduce properly when telomerase is defective. Her work has important implications for researchers in cancer, fungal infections and the aging process.

Source:
http://www.nobelprize.org/nobel_prizes/medicine/laureates/2009/blackburn.html

About this contributor: An optimistic high school student, Alice enjoys expressing her thoughts and opinions through writing. She plays field hockey in her spare time.