Physics 370 Experiments

Not all of these are guaranteed to be available. Necessary equipment may be broken, missing or in use elsewhere. I reserve the right to assign specific experiments to specific individuals.

I strongly encourage you to develop your own experiments that are interesting and relevant to your goals. Please discuss your ideas with me. Anything you come up with that I like is a good idea.

 •  Charge to Mass Ratio of Electron  •  Half-Life of 137m Ba
 •  Radiation statistics •  Gamma ray spectroscopy
 •  CCD noise and sensitivity as a function of temperature  •  Real vs. ideal capacitance
 •  Impedance of a speaker system  •  Resistance and strain
 •  Resistivity vs. Temperature  •  Temperature Dependence of Diodes
 •  Range of alpha particles in air •  Microwave Optics
 •  Microwave reflectivity of water  •  Cratering
 •  Electron Microscopy •  Physical Oceanography
 •  Fluid Dynamics  •  Drag
 •  Beam bending  •  Ultrasonics
 •  Coefficient of Restitution  •  Properties of 3-D printer plastic
 •  Battery charge efficiency  •  Evaporation rate of salt water
 •  Pointing accuracy and repeatability of a telescope  •  Hysteresis of elastic bands
 •  Telescope resolution  •  Response of a resonant system
 •  Magnetic Fields  •  Plasma Spectroscopy

Want another idea factory? The International Young Physicists’ Tournement has a history of very interesting questions that lend themselves to investigation.       IYPT Archives

And another list of ideas, thanks to Dr. Jinghua Xiao, of the Beijing University of Posts and Telecommunications (BUPT) for several of these.

 •  Blackbody Radiation •  Coupled plastic water bottles draining -invert, connected by tube
 •  Coupled burning candles - bundled 2, 3,4… separation… •  Coupled drain holes drilled into the bottom of a container
 •  Coupled Metronome synchronization, 1-D, 2-D, 3-D?  •  Frequency response of speaker - variable mass?
 •  Hall Effect  •  Speed of sound in air - two speakers + o-scope
 •  Millikan Oil Drop Experiment  •  Zeeman Effect
 •  Small Signal Detection with Lock-Ins  •  Harmonic Motion - Torsional
 •  Faraday rotation  •  Noise
 •  Mechanical Chaotic Oscillator  •  Immiscible liquids in cylinder with axial oscillation (AJP Apr 2017)
 •  Laser scattering from liquid filled capillary (vary n)  

Determine e/m, the Charge to Mass Ratio of an Electron
An electron with known energy in a uniform magnetic field moves in a circular path. Measurements of relevant parameters allows you to determine the quantiy e/m for the electron. We have an apparatus dedicated to this experiment.

The Half-Life of 137mBa
This relatively short-lived excited isotope of Barium emits a gamma ray which can be detected by a Geiger–Mueller detector. Measuring the decay rate of a sample of Barium will enable you to determine its half-life. You will need to determine the operating voltage of the tube by first determining the plateau region. The curve you plot for the sample of 137mBa should show an exponentially decaying count rate. From this you can calculate the time it takes for the decay rate to drop by a factor of two, the half-life.

Radiation Statistics
There are many statistical aspects of radiation that bear investigation. The distribution of actual activity about some average value for the case of "constant" activity is interesting. Gaussian versus Poisson statistics also comes up.

Determine the Impedance of a Speaker
We have a function generator that you can use to determine the impedance of a sound producing device as a function of frequency. Might be good for audiophiles.

Parallel plate capacitor
We know the ideal parallel-plate capacitor, but how does a real one behave, there are edge effects

Magnetic fields
There are a variety of magnetic field systems that would be interesting to investigate using our Teach-Spin Hall probe. Measurements can be compared to theory for loops, solenoids, Helmholtz coils, and maybe even other systems.

Microwave Optics
Microwaves are electromagnetic radiation, as is light. They are subject to the same set of rules and phenomena that light is. You can make a microwave lens, diffraction grating, and even measure the index of refraction for microwaves in a medium via Snell's law. Measure the brewster angle of microwaves for several materials, thus determining the index of refraction for each.

Microwave reflectivity
What is the reflectivity and absorption of radar (microwaves) from water? Fog? Rain? Humidity?

Temperature dependence of resistivity
Measure the temperature dependence of resistance for something interesting, perhaps some wire, a resistor or a lightbulb. This might use the lock-in amplifier, or not.

Temperature Dependence of Diodes
Investigate the temperature dependence of the current-voltage (I vs. V) characteristics of some diodes.

Resistance and strain
It is expected that the resistance of a wire depends on the strain the wire undergoes. Maybe look at strain

Electron Microscopy
Find something interesting and clever to image/characterize/analyze using the electron microscope

Plasma Spectroscopy
Investigate the spectrum of the plasmas in our H and He spectrum tubes. Expect that there will be differences in the spectrum as a function of place in the tube you collect the emitted light from. Perhaps use a variac to change the excitation voltage (but check with me first, as this is a partly-baked idea and it depends on the nature of the regulation in the tube power supply). This will require using one of our fiber-optic spectrometers. Plasma

Evaporation rate of salt water
Does the evaporation rate of salt water depend on salinity? How? Anything else?

Physical Oceanography
How does the response to a periodic input depend on the bottom profile of a body of water? Are the resonant frequencies for water sloshing around measurably different? What other effects might you measure?

Gamma Ray Spectroscopy
We have computer controlled apparatus for this. You may find useful info at the LBNL, or at the Decay Data Search Site.

Fluid Dynamics: Reynolds number and viscosity
If you find fluids interesting, you could do something involving Reynolds numbers, or viscosity of a fluid, temperature dependence of viscosity...

Drag is a retarding force due to the motion of an object through a fluid (liquid or gas). Drag varies with speed, shape, and size. What is the mathematical relationship between drag and these factors?

Bending a beam
Investigate the bending of a center or uniformly loaded beam. This is engineering stuff.

We have an ultrasonics apparatus. High frequency sound propagates through materials.

Coefficient of Restitution
The rebound height of a bouncing ball depends on temperature, among other things. Find some spheres made of different materials, and measure the coefficient of restitiution for them as a function of temperature.

Material characteristics
There are many properties of materials, hardness, stretchiness, strength.... Consider materials used in commmon 3-D printers for example. This plastic may have very different properties pre- vs. post-extrusion. Define and characterize some of interest.

How far do α-particles go in air? What is the distribution of ranges? How does it depend on the energy of the alpha particles? How do you measure how far they go? Can the track be measured directly or indirectly?

Response curve of a resonant electrical or mechanical system
What is the response of a system to a periodic input? For a circuit, what is the current as a function of input frequency? For a mechanical system, what is the amplitude of oscillation as a function of the frequency of a periodic nudge?

Rechargeable batteries
How efficient are rechargeable batteries? How to define efficiency and measure it?

Hysteresis of elastic bands
How does the force vs. elongation curve for a rubber band behave?

Telescope Pointing accuracy, stability, and repeatability
How accurately does the telescope point? How repeatable is pointing between two, or a series of targets? How stable is it when tracking, or when static?

Telescope Resolution
How finely can it distinguish between two point sources?

Characterization of a CCD
What are the noise, sensitivity, dark current, and spectral characteristics of a CCD?

How does the size of a crater depend on the energy of the impacting object? How about the momentum, or the mass, or the impact angle?

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Updated: 25 Oct 2018