What
For baseline evidence#1 I have chosen to include a question from Quiz #4 in Chem 507 about LASER. This pre-assessment question was given by the instructor prior to teaching about LASER and my answer was " I don't know."Later evidence#1 includes a piece of my Spec project about LASER TV as well as a link to my whole project web-page.
For baseline evidence#2 I have chosen to include two questions from a quiz in Chem 501, which illustrate my struggle to comprehend the concept of the molecular orbital. On the other hand, the later evidence#2 shows my growth of comprehension for the molecular model as well as my ability to illustrate my understanding in drawing molecular orbitals for different molecules.
Baseline evidence#3 is from my application to the MCEP. This essay represents a project about ground level Ozone pollution in Wilmington, DE. Later evidence#3 is a PIM from the Environmental Chem 505 class.
How
The baseline evidence and the later evidence show my growth in the use of accurate scientific language. It is clear from the evidence that I did not have prior knowledge or understanding of how LASER works. The later evidence#1 is a web-project on LASER TV, which is an example of application of scientific concepts of spectroscopic chemistry.
Later evidence 2 represents an accurate representation of the combination of two s orbitals and two p orbitals. Moreover later evidence#2 represents bond order and bond length.
Later evidence#3 shows my growth in the use of accurate scientific language. Working on a PIM on the death of Alexander Litvinenko, a former Russian security officer, represents my growth in the use of accurate scientific language in environmental chemistry, especially in toxicology.
Why
The only prior knowledge I had about LASER was just some applications in certain recent products. I never knew nor studied how LASER works, or even the meaning of the word LASER. The later evidence shows not only my understanding of LASER but also an application of it. LASER web-project illustrates the specific application of light amplification by stimulated emission of radiation in designing the laser TV. Furthermore, this project covers how LASER works, main components to create a laser beam, and an application of Boltzmann equation which was a main topic in Spec Chemistry class.
I used a piece of evidence from Chem 501 to show my initial struggle when the molecular orbitals theory was introduced for the first time. Later, when the same concept was offered for the second time, in Chem506, I started to develop a deep understanding of the MO theory which is used to describe the bonding in molecules. The symmetry properties and relative energies of atomic orbitals determine how they interact to form molecular orbitals. Moreover, the distance between the atoms must be short enough to provide good overlap of the orbitals. The concept of bonding/ antibonding orbitals is due to the concentration of electrons between two nuclei as well as if the bonding orbitals have higher or lower energy than the initial atomic orbitals. Homonuclear diatomic molecules have identical energies where both atoms contribute equally to a given MO. However, in heteronuclear diatomic molecules such as HF, where fluorine is more electronegative than hydrogen, the atomic orbitals have different energies resulting in unequal contributions from the atomic orbitals. As the energies of the atomic orbitals move farther apart, the magnitude of the interaction decreases. The atomic orbital closer in energy to an MO contributes more to the MO.
In environmental chemistry class, I was introduced for the first time to Toxicology, the study of poisons or toxins, as well as to radioactivity and nuclear energy from the standpoint of detection, isolation, identification, and determination of their effects on the human body. Researching the mystical death of Alexander Litvinenko, a former Russian security officer, gave me the opportunity to approach radioactivity from a new standpoint. The unstable radioactive nuclei spontaneously decomposed by emitting a small particle that is very fast moving and carries with it a great deal of energy. An alpha particle is a radioactive emitted particle that has a charge of 2+ and mass number of 4 and it is identical to the helium nucleus. A beta particle is an electron, which is formed from the spilt of a neutron into a proton and an electron in the nucleus. Gamma rays are an emission by the nucleus which carry huge amounts of energy concentrated in one photon and possesses no particle mass. Although alpha and beta particles are energetic, they can't travel far within the human body; they lose their energy and slow down as they collide with more atoms. Gamma rays are penetrate the most and therefore are the most damaging of the three. The death of Alexander Litvinenko was a unique case, in which radioactive material was used to assassinate him. The fact that Alexander ingested 210Po from his meal is an example of a brutal method to kill any human.
Conclusion
The only Spec topic that I previously taught in my classroom only included electromagnetic waves. I did not focus on chemistry of light, but used it as an introductory piece to study the atomic structure, especially electrons. Now, I realize the importance of Spectroscopic Chemistry, furthermore I enjoy teaching some of its' applications. Working on LASER for my web-project as an assignment for Chem 507 as well as working on LASER equipment in the Spec lab and observing the intensity of LASER light gave me insight to approach Spec chemistry in my classroom in more depth. Now my students enjoy more topics on colors, lights, spectrums, and for sure LASER. Moreover, in Chem 507 I was introduced for the first time to Boltzmann equation which gives the ratio of the atoms at two energy levels. However, this equation is used to explain how laser beam is created. Studying the MO in two different chemistry courses helped me not only to understand, but also to explain many chemical phenomena, such as polarity or oxygen molecule as well as para/diamagnetic properties of many molecules.
In addition the death of Alexander Litvinenko was an interesting way to study radioactivity and its effects on human health.
|