Chemistry Department
Texas A&M University
The diffraction experiment contains a red and a green laser that diffract on slides with various patterns. Stripe patterns give rise to one-dimensional diffraction images, reminiscent of the double slit experiment. Square patterns and more complicated shapes produce two-dimensional diffraction images, which can be used to illustrate crystallography (see figure). The effect of different pattern sizes, as well as the effect of the different wavelength can be shown on the diffraction image. This effect can also be used to demonstrate the appearance of the diffraction image in a high-resolution vs. a low-resolution crystal structure (smaller features give rise to larger angles of diffraction). Finally, as illustrated in the figure, the diffraction image can be calculated from the Fourier transform of the pattern.
This experiment is a college level laboratory experiment to illustrate the underlying principles of NMR. It is carried out over three lab periods of three hours each. The experiment is performed on a NMR spectrometer that we specifically built for this purpose, operating at the earth's ambient magnetic field. The spectrometer represents all of the features of a modern NMR spectrometer in a simplified manner, without the need for complex radio-frequency electronics. Measurements include spin-echo experiments, spin relaxation time measurements, and diffusion measurements using a pulsed field gradient. During the laboratory periods, students experience a hands-on introduction into pulsed NMR techniques and instrumentation, and into data acquisition techniques. A specially designed software is provided for independent data processing.
This experiment is a demonstration of an enzymatic reaction from the citric acid cycle, a set of reactions that provide energy to the cells in the human body. The experiment is aimed at K-12 students (grades 5-12) under the supervision of an instructor who is familiar with safe laboratory practices.