March 2015: 4-Point Probes from PVC
In the Physical Electronics lab, we use a device called a 4-Point probe to measure the resistance of a semiconductor. We own three of the commercial probes. The construction of the probe is quite simple so we have started building a similar probe in house. The first prototype is shown in the picture at the right and mostly consists of a PVC housing and four sewing needles. For the first data from this prototype, the results are very close to the commercial system.
February 2015: Thin film thickness.
In several upper division labs, we deposit thin layers of metal. The common way of measuring the deposited thickness is to use a QCM meter. The QCM meter is quite is expensive so we do not own one. This winter, we have begun experimenting with ways of measure resistance during the deposition. In theory, the resistance should be related to the thickness. In the picture at the left, a microscope slide is coated with aluminum in the center. The black strips on the ends are where the wires are connected to the glass slide. As the aluminum is added to the center region, the resistance between the black strips decreases. This method will be tested during the spring quarter of Physical Electronics.
January 2015: E/M tubes.
One of the hardest sections of physics for many physics students is understanding how magnetic fields work. Since students can’t see the fields, it is hard for them to visualize how the fields flow and interact with matter. The e/m Apparatus gets around some of these problems by making a stream of electronics visible. We still can’t see the fields, but we can see how the electron stream interacts with the fields. In the vacuum bulb, helium gas ionizes when electrons strike it and emits a greenish light that can be seen. Several donors have given money to help buy additional e/m hardware so that this experiment can be done in the lower division labs. In the picture at the right, the latest two purchases are shown ready for action.
December 2014: Modern Physics Lights
Dr. Liebrand’s Modern Physics students sent two separate beams through a beam expander (a microscope objective focused the light onto a micron-sized pinhole) and into a Michelson interferometer with a translating stage. The goal was to model a Fourier Transform Spectrometer with two signals in it. The picture at the left shows the interference pattern from the two separate laser beams.
November 2014: Research Presentations
At the annual department chapel, the senior physics majors presented a 10 minute talk on their summer research. The topics included the Earth's magnetic field, simulated proton CT scans, molecular super-rotors, bimolecular dynamics, and hazardous material containment.
September 2014: Graphite with the PVC STM
During winter quarter, the nanotechnology students built scanning tunneling microscopes out of PVC. Over the summer, Dr. Ekkens refined the design a bit to improve operation of the microscope. As a result of those refinements, nice pictures of carbon atoms in the graphite structure were obtained. In the image at the left, the bumps are electron clouds over the hexagonally-arranged carbon atoms. The image is about 4.6 nm wide and the bump spacing is about 0.25 nm. Resolution on the microscope is a bit better than 0.1 nm which isn't too bad for $40 of PVC and a guitar amp pickup from Ebay.
An article about the PVC microscope was published on the WWU website and a technical article on the build process is in progress.
Summer 2014: Molecular Biophysics Research
Rebekah Hawkins has just concluded her summer research project studying the dynamics of the alanine dipeptide molecule. The study of this simple biomolecule should shed light on the general problem of protein folding. Techniques and methods learned during this study will be used to study larger polypeptides and proteins. Rebekah plans to report on her work at the Murdock Undergraduate Research Conference this coming November.
June 2014: Summer Science Camp
The school year is over and this is the time for summer camps. The physics department helps with local science camps for grade-school children. Three days this month, the campers learned about motion, sound, light, magnetism, and electricity.
Some of the activities were more popular than others. The van der Graaf generator was one popular activity that everyone - even the staff - needed a turn or two to play with. The young lady in the picture has one hand on the van der Graaf generator and her hair is responding.
June 2014: Field Trip to B Reactor.
The General Physics class and the physics majors took a trip to see the B Reactor at Hanford, WA. In the picture, we are standing in front of the reactor core. The end caps for some of the 2004 tubes are visible behind the group.
April 2014: Light Emitting Diodes.
In Physical Electronics lab, we study light emitting diodes (LED). LEDs emit a characteristic color. The color depends on the type of semiconducting material used and the temperature. In the picture at right, the yellow light is changed into green by submerging the LED in liquid nitrogen. This lowers the temperature from about 300 K to 77 K. We also used the liquid nitrogen to make some ice cream.
March 2014: Making nanoparticles.
For the next-to-last lab in Nanotechnology, we made nanoparticles. The process started by depositing a thin layer of gold on a wafer. Then the wafer was heated in an oven to the point where the layer collected into particles. In the AFM picture at the left, the particles are about the size of a red blood cell (1 micrometer).
February 2014: Using the PVC STM.
The time finally arrived to turn on the PVC scanning tunneling microscopes and image nano-scaled stuff. With a little work, all four lab groups were able to get their microscopes to take images. The group shown in the picture saw the smallest feature ever seen in the history of PHYS 331 (Intro to Nanotechnology) at WWU with a 16 nm trench.
January 15, 2014: PVC STM.
The PVC scanning tunneling microscope that we are building for lab in Nanotechnology is coming together nicely. The connections from the computer come into the green boards and then are wired to the white board where our electronics reside. The stepper motor is clamped onto the PVC STM with a hose clamp - we are really going high-tech.
January 2014: Cutting Metal.
The second quarter of Experimental Physics has started off with learning to cut metal. In lab, we machined one piece of aluminum (6000 series alloy) using the end mill and another piece of aluminum (2000 series alloy) using the lathe. The two parts pictured are the ones cut on the lathe. They will be used in the Introduction to Nanotechnology Lab as motor couplings.
In a rare break with tradition, we managed to cut threads the hole in the top and the side without breaking any cutting taps.
October 2013: Slow-motion launch.
As the leaves start to fall, General Physics and Principles of Physics get to shoot projectiles. This year the weather was good and the rockets flew far. Click here to see a slow motion video of rockets leaving the launch stand. The condensation from the rapid pressure changes shows up nicely.
September 2013: Summer Research
Dr. Liebrand has been working on solar projects for the last several years. This summer, Dr. Liebrand and physics major, Thomas Blum, have worked on a process to increase the output of solar cells.
August 2013: Summer Research
As mentioned in a previous news post, the Physical Electronics lab has been using a boron process to make pnp transistors since Spring 2012. The process needs refinement, so this summer Dr. Ekkens spent a bit of time working on the process. In the picture, the color on the wafer is where the boron has been cooked onto the wafer surface.
February 2013: Spring Constants
In Conceptual Physics, we study properties of solids. One of the properties for consideration in lab this week was spring constants. We looked at the spring constant of plastic bags by stretching them until the bag broke. We found a standard bag can support up to 12 kg for a short time.
October 2012: Rockets
School has just started, the leaves are falling, and so are the rockets. October always brings the rocket lab in General Physics and Principles of Physics - a chance to study projectiles in motion while enjoying a sunny day outside. In the picture at the left, two red spots are just visible in the center of the sky. One is a rocket going up and the other is another rocket coming down. The trick to surviving the lab is to not be under the rocket as it comes down.
September 2012: Summer Projects
Many of our students leave for the summer. A number of them were doing research or internships at companies and labs scattered around the country. One physics major, Darryl, did spend the summer here working on building a ring interferometer. The laser head, some of the mirrors, and the slip-ring assembly are shown in the picture. By the end of summer it was mostly working.
May 2012: pnp Junction.
In Physical Electronics lab, we have tried making a transistor as one of the final labs of the quarter. Over the past eight years, several different build processes have been tried but the transistor has never worked. This year was different and with a new boron process, the device shown in the picture works as a pnp transistor. We still need to improve the process a bit so the transistor is a bit more reliable and has a better gain. Now . . . only 499,999,999 more and we will have a single CPU.
April 2012: Trebuchet!
One of the advantages of a small physics department is that students can use the lab space and machine shop to work on personal projects. Darryl has built a number of projects during his time at Walla Walla University. This spring has seen the test firing and exhibition firing of his Mark II trebuchet.
March 2012: Superconductivity.
For the last part of Nanotechnology Lab, we made a Type-II superconductor. Once it was baked, it was time to break out the liquid nitrogen and test it. Sadly it failed, but we had the ones from previous years to play with. In the picture on the left, a permanent magnet is levitating over the superconductor.
February 2012: Ferrofluids.
In the nanotechnology lab we have been looking at several magnetic systems. The most recent lab involved ferrofluids. Ferrofluids are most often used in sealing the area around rotating shafts.
In our lab we just looked at the different shapes we could make while applying external magnetic fields. In the picture at the right, a magnet from a hard drive is held under the glass dish and the spikes are at the approximate ends of the magnet. While a good time was had by all, some of the magnets still are stained.
A short video of the fun is here.
February 2012: STM Results.
The scanning tunneling microscopes are complete and imaging. They have plenty of room for further improvement, but the basic functionality is there. In the picture below, the scanning tip is shown on the left. The tip is held in the black piece and extends down to the copper sheet that is being scanned. On the right is data from a calibration standard. The field of view is 3000 nm which means the resolution is 300 nm or better for this microscope.
January 2012: Nanotechnology.
Introduction to Nanotechnology is being taught this winter quarter. In lab we are again building a scanning tunneling microscope. Two years ago when the course was last taught, the best resolution from the student STM was about 1,000 nm. We are trying to best that.
This year we have replaced some of the analog electronics with a higher-powered data acquisition card (NI-6229). Three labs in January got us to finished hardware. In this picture, the electronics are being connected and tested. The next steps are to load in a sample and measure resolution.
December 2011: Circuit Boards.
A new lab this year was building circuit boards in Experimental Physics I. We used simple equipment and processes so the result is environmentally friendly (we are using a Ferric-Chloride-free process) and inexpensive enough that the students can make circuit boards at home. The total cost of the lab is about $5 per board and does not require anything beyond the parts available at ACE Hardware, Ebay, and Walmart.
November 2011: New Oscillosopes.
B&K Precision Instruments has donated to the physics department seven 2530B digital oscilloscopes. The new scopes replace cheaper scopes and allow much easier transfer of data to the computer. So far, the features on the new scopes have been used heavily in upper division labs and for robotic club testing.
In the picture, the chaotic behavior of a diode circuit is being tested and displayed on the new scope. The xy-scan mode of the new scopes allows for a much better visualization of certain effects.
September 2011: Zeeman Effect
The big summer project that Calvin worked on was building the Zeeman Effect apparatus for Dr. Liebrand. This project has been tried during past summers but has never showed the right result. This summer was different and with a little help from Darryl in depositing the right amount of aluminum on some optical parts, Calvin built and aligned the system. One week before school was to start, the splitting effect was documented. Good job, Calvin.
The completed Zeeman apparatus will be used in the Modern Optics Lab which Dr. Liebrand teaches every two years.
August 2011: Machine Shop!
This summer, two physics majors - Darryl and Calvin - worked on several projects in the Physics Department. One of the biggest projects was to create a machine shop. Space was cleared in a storeroom and a large counter was installed. The existing band saw and end mill were mounted on the counter top. A lathe and table vice were purchased to add to the collection. Every week more tools and supplies are purchased. A drill press is the next big piece of equipment to install.
The machine shop is already in heavy use. Much of the summer work that Darryl and Calvin did included making parts on the existing equipment or waiting for the next tool to arrive. Since space in the shop is limited, the end mill and lathe are of hobby size. Parts larger than 6 inches need to be fabricated on tools found in the engineering shop.
June 2011: Finals!
It is finals time and students are studying hard and taking hard tests. Dr. Ekkens allows a sheet of equations for his tests. However, it is critical to get the right equations for the subject material. While Maxwell's Equations are amazing and accent any wardrobe choices with a touch of class, they are of limited help on a test covering semiconductors.
May 2011: LIGO Field Trip
The Astronomy Class usually takes a trip to the gravitational wave detector (LIGO) at Hanford. This year the physics majors and some honors students joined the trip. The system is being updated to Advanced LIGO so we were able to see some of the new hardware ready for installation.
April 2011: Chaos
Three senior physics majors are taking a directed study course this quarter covering chaos. Each week, the class reads a chapter in a history of chaos book. Then during class, each person works on a computer program or other project to model the chaotic system that was covered in the reading. In the picture, the design on the left was created using three rules, a random number generator, and about 30 minutes of programming time. The fern on the right uses six rules and was not assigned for class.
Last update on April 23, 2015