Brief description of individual experiments
    Last Changed Fall 1988

Experiment I: Sound Waves

In this experiment, the students will study an example of a mechanical wave, namely a sound wave. The students will do this experiment by setting up standing waves in an air column and measuring the resulting resonant wavelength. This will help the students determine the speed of the sound waves in air. This result will be checked by calculating the speed of sound using atmospheric data.

In this experiment, the students will study another type of wave, namely the electromagnetic wave. More specifically, the students will study the propagation of electromagnetic waves along a transmission line. The goal is to measure the speed of the electromagnetic waves in a coaxial cable and to determine some properties of the coaxial cable itself. The students will accomplish this by studying the behavior of standing waves and pulse echoes in the transmission line.

For the next two experiments the laws of reflection and the laws of refraction of light in the "ray" limit and image forming systems are studied. This knowledge has a fundamental interest and it provides a theoretical background for the use of image forming optics and the student capability to manipulate such components as lenses, morror systems, and lasers in the remaining portion of the laboratory.

In this experiment the student will study such things as total internal reflection, the optics of a prism, and apparent thickness.

In this and previous experiments the laws of reflection and the laws of refraction of light in the "ray" limit and image forming systems are studied. This knowledge has a fundamental interest and it provides a theoretical background for the use of image forming optics and the student capability to manipulate such components as lenses, morror systems, and lasers in the remaining portion of the laboratory.

In this experiment, the students will continue to explore geometrical optics by studying the optics of simple curved mirrors and lenses. More specifically, the students will study a concave mirror and double concave and double convex lenses.

The polarization of light is studied. This is the vector nature of electromagnetic waves and is studied by the use of polarizing analyzers, quarter wave plates, and other devices. In addition the role of reflection in Brewster's angle is addressed. Thus, this experiment provides both an understanding of the laws of polarization and a foundation for the remaining part of the laboratory.

This is the first experiment in PHYS 375 which addresses the core area of the course, i.e., the subject which is the primary objective of the laboratory. That is, the wave behavior of light and its role in interference phenomena. In addition we study the nature of optical light source. Here we use a laser as the optical source and study the patterns produced by single, double and multiple slit interference. These one-dimensional multiple slit interference with the use of a 2-D mesh. This data is recorded using a microcomputer to provide a more complete data set, and , secondly, an introduction to the use of computer in laboratory experiments. Finally a mechanical measurement of the wavelength of the laser radiation is accomplished by using diffraction from a machinist's ruler.

In this experiment the student addresses both a more sophisticated instrument for the analysis of the spectral characteristics of light - the diffraction grating - and the study of the spectral structure of the light from various laboratory sources (atomic line emission from plasma sources, as well as the laser source). The diffraction grating essentially uses the principles of the multiple slit interference addressed in the previous laboratory series, in a more sophisticated manner. This extension permits a more accurate analysis of the wavelength structure of light in a manner which is practical for the laboratory. Various atomic sources are observed with the diffraction grating and the wavelengths of the emission features are measured. The separation of the emission lines in the sodium doublet is measured in this experiment and in the next two experiments. This permits a more objective intercomparison of different optical interferometric techniques for the study of line emission.

 This gives the student experience in the high accuracy which may be achieved in optical measurements.

In this experiment the student uses the Michelson Interferometer. This is the first of the classical interferometric devices which is considered in this course. The Michelson Interferometer is used to study the atomic emission spectrum of sodium.

The Michelson Interferometer explicitly uses time delay for the analysis of the wavelength structure of light. This gives the student experience in the fine optical and mechanical adjustments required for interferometric equipment and permits a continuation of the high accuracy feasible in optical measurements using student equipment, i.e., of the order of 0.01 percent.

The study and use for practical measurements of the Fabry-Perot Interferometer continues the exposure of the student to these techniques of classical optical intrumentation. They provide some analytic background, operational experience and measurements for analysis. The Fabry-Perot Interferometer is another type of interferometer that allows even higher accuracy, as well as illustrating a different class of applications. To continue the common thread for concree intercomparison, the Fabry-Perot Interferometer is used to measure the sodium-emission spectrum. The measurements with the Fabry=Perot Interferometer permit an even more accurate determination of the separation of the sodium doublet.

 It also permits the measurement of the width of the emission lines and allows, by consideration of the doppler width, study of the physical processes in plasma light sources.

This experiment addressestwo independent topics, which characterize the historical role of optical experiments in addressing the role of quamtum mechanics in physics. Most of the early developments in quantum mechanics were stimulated by optical experiments, that is, the structure of the spectra of atomic light sources, the wave characteristic of electron diffraction, the photoelectric effect and the fine structure and hyperfine transitions of atomic species. The first portion of this experiment, the photoelectric effect, both illustrates the particle nature of light and evaluates one of the fundamental constants of nature. It is also a phenomena which governs a wide variety of practical instrumentation (vacuum tubes, photocathodes, etc.). In this case we are observing and measuring the particle aspect of the wave phenomena which has been studied in the earlier experiments.

 The second portion of this experiment consists of the demonstration and measurement of the wave diffraction of an electron beam by a crystalline material. This diffraction mechanism provides the consideration and a preliminary understanding of Bragg scattering by crystalline material. This phenomena is used, as a tool, to illustrate that an electron beam has wave characteristics. The student then measures diffraction parameters to define the dependence of the wavelength of the electron upon the acceleration voltage of the electron beam.

 Thus, two of the experimental fundations of quantum mechanics and their optical origins are illustrated to the student.