78235 Experimental Physics

Experiments

There are six different experiment sequences which you can choose from:

The start date and report due dates for these labs are differernt depending on whether you are in the Tuesday or Thursday lab section. For the Tuesday lab section, the dates are:

For the Thursday lab section, the dates are:

President's day, Spring Break, and GM Week force the schedule to be broken up a little, but you are always welcome to work outside of class on taking measurements, and hand your writeup in early. Everyone's final lab report is due May 1, before final exams begin.

These are the experiments set up for the Spring 1998 term. They are described in detail in the course notes. Under each experiment is a brief list of suggested measurements you should make with each apparatus. A quality job on each topic, or with an appropriate substitution, is worth an A for that lab.

Experiment 1: The Voltage Divider (TA: Mike Stukowski)

Minilab only. Determine the relative gain and phase curves for a few combinations of R and C, or R and L. Determine time constants by fitting your data and compare your results, with uncertainties, to manufacturers specifications on the components.

Experiment 3: Gravitational Acceleration and the Pendulum (TA: Davienne Monbleau)

Minilab only. Determine the period from mean and standard deviation of several measurements, and for different initial angles. Test first order deviation from the small angle approximation. Estimate g and compare to the accepted value, with uncertainty.

Experiment 4: Dielectric Constants of Gases (TA: Davienne Monbleau)

Minilab only. Determine the dielectric constants for air, carbon dioxide, and nitrogen, and compare with uncertainties to the accepted values. Bonus points if you can measure helium.

Experiment 5: Resistivity of Metals (TA: Matt Frederick)

As a minilab. Measure resistivity of aluminum alloys and pure aluminum at room temperature. Use at least two rods of different diameters and show that the results scale correctly. Estimate systematic uncertainty and compare to accepted values.

As a two-week lab. Measure resistivity of aluminum alloys, pure aluminum, copper, lead, and tin, all at room temperature. Measure pure aluminum and aluminum allow also at liquid nitrogen temperautre, and discuss the differences. Estimate systematic uncertainty and compare to accepted values.

As a final lab. Same as for two-week lab, plus measure pure aluminum at several other temperatures. Compare the resistivity as a function of temperature to the Bloch-Grueneisen formula.

Experiment 6: Atomic Spectroscopy (TA: Mike Stukowski)

As a two-week lab. Calibrate the Jarrell-Ash spectrometer and determine the linearity. Determine the Rydberg constant from hydrogen, and compare with uncertainties to the accepted value. Analyze the line widths in hydrogen.

As a final lab. Same as for two-week lab, plus a determination, with uncertainties, of the H/D mass ratio from the splitting of the spectral lines. Your calibration should include both He and Hg spectra, and you should take some care to optimize the setup for resolution.

Experiment 7: Johnson Noise (TA: Mike Stukowski)

As a two-week lab. Calibrate the gain-bandwidth curve of the amplifier, and determine k from the noise as a function of R. Compare with uncertainties to the accepted value.

As a final lab. Same as for two-week lab, plus a further investigation of the noise spectrum using the Fast Fourier Transform properties of the oscilloscope. (If anyone would like to learn how to use MATLAB to calculate the FFT, let me know.)

Experiment 8: The Faraday Effect (TA: Mike Stukowski)

Minilab only. Determine the Verdet constant for water, using the HeNe laser and an oscilloscope to determine the optical rotation. Calculate the uncertainty and compare to the accepted value.

Experiment 10: Radioactivity (TA: Matt Frederick)

As a minilab. Demonstrate the Poisson and Gaussian probability distributions for a variety of different average count rates, or determine the half life of the metastable excited state of 137Ba, including the uncertainty. Bonus points if you can do both.

As a two-week lab. Demonstrate the Poisson and Gaussian probability distributions for a variety of different average count rates. Also, use the neutron oven to determine the half lives of 116In and also 108Ag and 110Ag, and compare to the accepted values with uncertainty.

As a final lab. Same as for two-week lab, plus measure the half life of 137mBa. For 137mBa, you should also explore using a NaI detector instead of the Geiger counter to reduce background from 137Cs decay.

Experiment 11: Positron annihilation (TA: Davienne Monbleau)

As a two-week lab. Measure the gamma spectrum from 22Na using the NaI detector and single channel analyzer, and determine the activity of the source. Set up for coincident photon detection, and demonstrate the back-to-back nature of positron annihilation.

As a final lab. Same as for two-week lab, plus use the setup to measure the gamma-gamma angular correlation from 60Co decay. You should take some time to use what you learned with 22Na to understand the two-gamma cascade nature of 60Co decay.

Experiment 12: Compton Scattering (TA: Davienne Monbleau)

As a two-week lab. Carry out an energy calibration of the NaI detector. Demonstrate Compton scattering and determine the scattered photon energy as a function of angle. Determine the mass of the electron, with uncertainty, and compare to the accepted value.

As a final lab. Same as for two-week lab, plus use the count rate data to determine the cross section for Compton scattering as a function of angle, including the various efficiency factors. Alternatively, you can compare the effectiveness of the setup with and without detecting the recoil electron, and analyze the various contributions to the backgrounds.