Browsing by Author "Christopher Gorman, Committee Member"

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    Development of Sensorial Experiments and their Implementation into Undergraduate Laboratories.
    (2009-07-22) Bromfield Lee, Deborah Christina; Melissa G. Jones, Committee Member; Christopher Gorman, Committee Member; Maria T. Oliver-Hoyo, Committee Chair; Reza Ghiladi, Committee Member
    “Visualization†of chemical phenomena often has been limited in the teaching laboratories to the sense of sight. We have developed chemistry experiments that rely on senses other than eyesight to investigate chemical concepts, make quantitative determinations, and familiarize students with chemical techniques traditionally designed using only eyesight. Multi-sensory learning can benefit all students by actively engaging them in learning through stimulation or an alternative way of experiencing a concept or ideas. Perception of events or concepts usually depends on the information from the different sensory systems combined. The use of multi-sensory learning can take advantage of all the senses to reinforce learning as each sense builds toward a more complete experience of scientific data. Research has shown that multi-sensory representations of scientific phenomena is a valuable tool for enhancing understanding of chemistry as well as displacing misconceptions through experience. Multi-sensory experiences have also been shown to enrich memory performance. There are few experiments published which utilize multiple senses in the teaching laboratory. The sensorial experiments chosen were conceptually similar to experiments currently performed in undergraduate laboratories; however students collect different types of data using multi-sensory observations. The experiments themselves were developed by using chemicals that would provide different sensory changes or capitalizing on sensory observations that were typically overlooked or ignored and obtain similar and precise results as in traditional experiments. Minimizing hazards and using safe practices are especially essential in these experiments as students utilize senses traditionally not allowed to be used in the laboratories. These sensorial experiments utilize typical equipment found in the teaching laboratories as well as inexpensive chemicals in order to aid implementation. All experiments are rigorously tested for accuracy and all chemicals examined for safety prior to implementation. The pedagogical objectives were established of to provide the ability to develop and stimulate students’ conceptual understanding. The educational assessments of these experiments are are fashioned using the framework chosen (Marzano and Kendall). All the experiments are designed as collaborative, inquiry-based experiments in aims of enhancing the students understanding of the subject and promote critical thinking skills. These experiments use an investigative approach rather than verification methods. Terminology and misconceptions of the experiment were evaluated to prevent misunderstanding or confusion during the experiment. Interventions to address these misconceptions and learning problems associated with the experiment were developed. We have developed the Learning Lab Report, LLR, as an alternative model for the traditional laboratory reports, with the goal of transforming the traditional reports into something more useful for both students and instructors. The educational strategies are employed to develop this format in order to promote students to think critically about the concepts and take an active involvement in learning. From the results of the LLR, all experiments were reviewed and re-written to address any learning problems. The sensorial experiments study several topics usually covered in the first 2 years of the chemistry curriculum (general and organic chemistry courses). The experiments implemented, organic qualitative analysis, esterification kinetics, Le Chatêlier equilibrium, thermometric titrations and ASA kinetics, worked effectively as students were able to draw correct conclusions about the concepts from the data obtained. An olfactory titration using the smell of the rutabaga vegetable has been developed and thoroughly tested. The LLR was utilized with the equilibrium, titration and acetyl salicylic acid experiments. The details of the development, implementation of these sensorial experiments and the LLR and student results are discussed.
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    The role of surface chemistry in defining the energetics and kinetics of single electron tunneling through individual gold nanoparticles
    (2003-06-24) McConnell, Wyatt Parks; Orlin Velev, Committee Member; Daniel L. Feldheim, Committee Chair; Christopher Gorman, Committee Member; Edmond Bowden, Committee Member; Charles Boss, Committee Member
    The properties of nanoscale materials are often dominated by their surface chemistry due to their increased surface-to-volume ratio. Metal nanoparticles with diameters smaller than ~12nm show a technologically relevant non-linear current-voltage response known as single electron tunneling. Gold nanoparticles offer an excellent platform for understanding how the surface chemistry of the metal island in a single electron-tunneling device can affect the current response of the structure. This is because the surfaces of these particles can be custom tailored using thiol-based self-assembled monolayer protocols that have been extensively developed for planar gold substrates. This dissertation describes STM measurements of single electron tunneling through individual gold nanoparticles of various sizes and surface chemistries in both air and solvent at room temperature and pressure. The voltage step-width of the resulting coulomb staircase was shown to be dependent on particle size. Solution experiments show that the energetics of single electron tunneling of particles with certain surface chemistries is dependent on the composition of the solution, while other surface chemistries can produce particles that give a stable single electron tunneling response in a wide variety of local chemical environments. Using acid and base terminated surface chemistries, particles were made that showed a defined response to a specific change in the local solution pH. The kinetics of single electron tunneling was also shown to be highly dependent on the chemical bond formed between the capping ligand and the metal particle.