Category Archives: Sciences

The Camera – Katie Brooks Boone

By | Sciences | No Comments

Katie Brooks Boone
Physics
Mr. Carrell
May 16, 2013

The camera was seen in earliest form as the “camera obscura.” The idea for this “dark chamber” was first recorded by an ancient Chinese philosopher named Mo Ti who discovered that focused images can be created when light passes through a small hole and into a dark area. The inverted image created by this light would translate to a picture. Other ancient philosophers also studied this idea by viewing solar eclipses through a pinhole to create a sharper image of the sun. Eventually, the idea of observing projected images was done in a dark room with a pinhole on the opposite wall, hence the name “camera obscura.”

Around a century later, the camera obscura became a portable drawing device for copying projected image. And in an effort to more permanently preserve these images, many experiments were done with various light exposures to automatically create detailed copies of the projected image. Over time the portable camera became more efficient and it became possible to photograph images with exposure to a light-sensitive material. In 1826 Joseph Nicephore Niepce made the first permanent photograph with a sliding wooden box camera. As time progressed, the method of exposure in portable cameras became much quicker and more accurate. More light-sensitive photographic materials were used to create clear images, and mechanical shutter devices were incorporated to allow shorter and more accurate timed exposures. In the 1920s, the electronic video tube was invented which allowed further development of a projected image. This device converted optical images into electrical signals. And naturally, more efficient models were created and new digital forms of photography quickly replaced the old film-based cameras.

Today camera’s are used every day by millions of people who do not think twice about the number of megapixels in their iphone camera. But the invention of the camera has made an unfathomable impact on the culture we live in. Newspapers, magazines, and books all are heavily supplied with pictures taken by thousands of high-tech cameras that we easily take for granted. Without it, society would lack the ability to preserve beautiful images that will last for a lifetime.

Ethan Shaw Actinium Paper

By | Sciences | No Comments

Ethan Shaw Mr. Carrell 10B Chemistry May 17, 2013

Click to Download PDF Version 

Throughout today’s society the mention of radioactivity largely occurs as a political scare tactic or environmentalist jargon. Despite the many negative connotations, radioactivity is still a very new and largely unexplored concept. The principle was first observed by French scientist Henri Becquerel in 1896. He hypothesized that that phosphorescence might be related to the effect of X-rays in cathode ray tubes because both caused materials to glow in the dark after exposure to radiation. While testing various phosphorescent salts, he noticed that the uranium salts—unlike all the others—blackened the photographic plate which held them. This same phenomenon was later observed with non-phosphorescent uranium salts, and thus Becquerel’s hypothesis proved wrong. His experiment, however, paved the way for further research over the next few decades. Although the dangers of radiation were not initially realized, Becquerel’s findings nonetheless paved the way for the dawn of the nuclear era.

Technically, all elements undergo radioactive decay. For the vast majority, however, an element’s common isotopes are stable and this process is very slow and thus negligible. There are thirty-eight elements classified as radioactive, meaning they have no truly stable isotope or are synthetic and always unstable. Generally, heavily radioactive elements are found toward the very bottom of the periodic table. Among these actinium is generally considered one of the most dangerous radioactive substances. It is the first element in row seven, and therefore this row is termed as the actinoid series. Actinium’s significance lies in its status as the first non-primordiali radioactive element to have been isolated. The key data points concerning actinium are as follows:

  • Atomic number: 89
  • Family: N/A (technically group #3, but this is debated due to its actinoid status)
  • Atomic mass: 227
  • Description: soft; silvery-white color
  • Solid at room temperature
  • Default oxidization state: +3
  • Location in periodic table: f-block, period #7

Interestingly, the account of actinium’s discovery raises much scholarly contention. André- Louis Debierne, a French chemist studying under the famous Pierre Curie, credited with the element’s name. While experimenting with the separation of rare earth oxide minerals from pitchblendeii around 1899, he discovered an unknown substance which he observed to be a hundred thousand times more radioactive than uranium. Although similar to lanthanum, its properties did not fully match up, and so Debierne decided to christen a new element, naming it actinium. Three years later, though, the German Friedrich Giesel—ignorant of Debierne’s claim—independently discovered the element and named it emanium. In placing radium impurities on a zinc sulfide screen, he noticed its emanationiii moving across the screen and giving off a unique phosphorescence. He thus named his discovery emanium, from the Latin “emanare” (“to flow out”). Although Debierne’s elemental name remains today and he has the chronological advantage, many modern scholars question the validity of his discovery and find more reliable proof in Giesel’s account. Regardless, both men made key contributions toward laying the foundation for the emerging field of nuclear engineering.

Though not universally synthetic, the vast majority of actinium is artificially produced through the nuclear irradiationiv of radium-226 and is therefore largely unstable. As a result, it has few practical uses and is generally created for laboratory research purposes. Actinium’s most common isotope is Ac-227, traces of which are found within uranium ore as a result of radioactive transmutationv (as Debierne observed). However, the quantities are very small (0.2

mg Ac per metric tonne U) and separating out the actinium is thus a very inefficient means of collection. This impracticality led to the current radium irradiation method. Notably, actinium itself is a source of neutrons just like the radium used to create it. Alpha, beta, and gamma particles make up the observed radiation spectrum and are named in order of penetration capabilityvi. Actinium provides beta particles with a source of neutrons to be converted and emitted as electrons. A similar process occurs in the release of alpha particles, which are pertinent in the treatment of cancer using radiation therapy. Even so, actinium—like all radioactive elements—is unstable and thus prone to transmute into various other elements and isotopes as a result of certain processes (such as fission). In truth, as German chemist Otto Hahn observed, actinium’s radioactivity seems to come from its decay products. Perhaps actinium’s actual significance lies in its propensity to create other, more useful radioactive substances.

Figure: an illustration of the actinium decay chain, involving radioactive transmutation.

i Also, synthetic or artificial. A primordial element is one that is stable and thus its current isotopes are hypothesized to have been in existence since the earth’s formation.
ii A common name for the uranium-rich mineral uraninite.
iii In chemistry, the gaseous product of radioactive disintegration.

iv Refers to the process of exposing a substance to neutrons.
v The process in which one radioactive element is changed into another.
vi The illustration given is that a sheet of paper will stop an alpha particle and a sheet of aluminum shielding a beta particle, but even a thick block of lead will only slow down a gamma particle due to its immense penetration power.

Sources Listed

“Actinium.” Wikipedia. Wikimedia Foundation, Inc, 26 April 2013. Web. 16 May 2013.

“Beta Particle.” Wikipedia. Wikimedia Foundation, Inc, 4 May 2013. Web. 16 May 2013.

Emsley, John. Nature’s Building Blocks: An A-Z Guide to the Elements. Oxford: Oxford University Press, 2001. Print.

Kirby, H.W. “The Discovery of Actinium.” Isis Autumn 1971: 290-308. Web.

“Radioactive Decay.” Wikipedia. Wikimedia Foundation, Inc, 14 May 2013. Web. 16 May 2013.

Thomas Jefferson National Accelerator Facility – Office of Science Education. “The Element Actinium.” Jefferson Lab. Jefferson Science Associates, n.d. Web. 16 May 2013.

Robert Mann – Bioplastics

By | Sciences | No Comments

Over the past few decades, a revolutionary idea has arrived on the scene: Bioplastics. One might think that anything that is supposed to be “environmentally friendly” or “green” must be a good idea. However, in their current state, bioplastics are inefficient. Bioplastics are a type of plastic that come from renewable sources such as vegetable fats and oils, corn starch, and many other sources. Many bioplastics decompose over time at the same rate as paper and do not rely on fossil-fuels like common plastics. Despite these positive effects, bioplastics are currently not worth implementing.

Even though bioplastics are not currently used on a large scale, they still have a variety of possible practical applications. Bioplastics.com sells products for molecular biologists to use in labs such as pipette tips, tubes, racks, and boxes. Each of these tools can be made from bioplastics. Many of the glass tools students use during experiments can be replaced with reusable and biodegradable instruments. Also, Bioplastics.us explores the idea of Biothane, which is a substance made from layers of bioplastics. Biothane is coated webbing already used in the military, medical field, and in sports. Biothane is also a key safety component in rock climbing and other related fields because it is used for harnesses, belts, and straps. Without a doubt, bioplastics are relevant to a wide variety of occupations and are becoming more available to the world.

Despite their variety of uses, bioplastics should not be implemented because of their negative effects. Discovery.com states that some petroleum plastics have less environmental effect than bioplastics. To create bioplastics requires a great amount of energy, and the energy put into making bioplastics outweighs the energy given back to the soil when they decompose. In addition, Time.com reports that not all bioplastics decompose, and they must be disposed of properly or else they will not break down. Some bioplastics can fully decompose (a Sun Chips bag) or only partially decompose (a water bottle where the cap does not break down with the rest of the bottle). Bioplastics are currently more of a hassle than a help. Thus, because bioplastics are a recent idea, they are only sometimes biodegradable and often use more resources than they give back to the soil.

In conclusion, bioplastics are relatively new idea that explores making objects that can return to the soil and look like soil. The definition of something that is compostable is an object that is biodegradable, disintegrates, and leaves no toxic material. Based on this definition, many bioplastics do not meet these criteria even though they are designed to meet each of these standards. Some objects made from bioplastic only partially disintegrate, while others break down very slowly. The availability of these bioplastics is scarce because they cannot be made quickly. The applications of bioplastics are in a wide variety, but again, the process is tedious and time-consuming. To conclude, bioplastics could be a great tool in the world’sfuture but are too unpredictable currently to make a significant impact.

Download the PDF

 

Works Cited

1. N. p. http://cordis.europa.eu/search/index.cfm?

fuseaction=proj.document&CFTOKEN=19120 617&PJ_RCN=7901178&CFID=6808047. CORDIS services, 1 June 2005. Web. 30 September 2012.

2. Chen, G. and Patel, M. http://en.wikipedia.org/wiki/Bioplastic#cite_note-2. Chemical Reviews, n. d. Web. 30 September 2012.

3. N. p. http://www.bioplastics.com/. BIOplastics, 2010. Web. 30 September 2012.

4. N. p. http://www.bioplastics.us/. Bioplastics Company, 2006-2012. Web. 30 September 2012.

5. Marshall, Jessica. http://news.discovery.com/earth/bioplastic-plant-plastic-evironmental.html. Discovery News, 6 December 2010. Web. 30 September 2012.

6. Dell, Kristina. http://www.time.com/time/magazine/article/0, 9171, 1983894, 00.html. TIME Magazine U. S., 3 May 2010. Web. 30 September 2012.

7. N. p. http://worldcentric.org/biocompostables/bioplastics. World Centric, 2004-2012. Web. 30 September 2012.

Possibility of Other Universes – Josh Moore

By | Sciences | No Comments

“Physicists have sought far and wide for an explanation of the universe which excludes the postulate of a divine being, and intelligent designer who created and will complete all things. One solution is the multiverse that our universe is really only one of the many options out there, that there are other universes that have spun off of this, or perhaps our universe is a spin off of the primary universe or what if this isn’t the primary universe?” The multiverse is the concept that there are an infinite number of universes beyond our own. It was developed by physicists to explain all of the coincidences that make life possible in our universe. (Multiverse, 2012). This idea becomes significant in the search for extraterrestrial life and the debate over evolution.

 

Keep Reading…