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This quarter we are teaching optics and its lab. The picture at the left shows the setup that we used to determine the index of refraction for a glass microscope slide. We are starting to merge the expensive world of precision optics with the cheaper world of 3D printing. In this setup, the holder for the microscope slide is 3D printed while the rest of the setup is very precise.
December is a busy half month. In the Physics Department, we set up the Christmas tree, had the annual Christmas supper with the majors, listened to or participated in the WWU Christmas Concert, had final tests, and gave or received grades.
By the middle of the month, all the loose ends are tied up and many of the students and teachers have left for vacation. The campus is quiet and waiting for the start of the next quarter.
During the early part of Modern Physics this quarter, cloud chambers were mentioned. They will be covered in more detail in Modern Physics II. This year we purchased a Thorium Lantern mantle to use as an alpha source so we used it as a demonstration in Modern Physics Lab.
This chamber is built the easy way. Dry ice is underneath the plastic box and the alcohol vapor is contained in the box. The thorium mantel is the white and pink piece in the upper portion of the image. The vapor trails are visible against the black plastic. Click on the picture at the left to get a video of the chamber in action.
This time of year, the trees outside the physics department are very colorful. The picture below at left is just outside the department office. Inside, the Modern Physics class is studying electron motion. As part of that study we use a scanning electron microscope to take pictures of several things - including the fruitfly below at right. Electrons don't have color so that picture that they create is just shades of gray. The magnification in this image is 35x.
Our 2018 - 2019 school year started with the Jumpstart session (and the Jumpstart supper) when we welcomed the new majors. A few classes have happened and work hours are assigned. Even some assignments are coming in. We are excited about the possibilities of the new year.
The Walla Walla Physics Department is enjoying a period of growth as seen in the chart below. For this year and the past two, we have the highest number of majors in recent history. We had a record number of student research projects over this past summer and recent graduates are going to good schools.
Another project for student research this summer is the Mossbauer System. This project has one student working on it with the goal to use stepper motors to shake a radioactive sample at exactly the right velocity. The starting place for the mechanical system was an old 3d printer bed.
This summer we have several research projects going on that are focusing on building new hardware. The Raman Spectroscopy project has two students working on it and is following the ramanPi instructions on Hackaday. So far, most of the month has been spent printing parts on the 3D printer (shown in the picture at right) and building up the electronics.
As part of the Modern Physics 2 class, we took a field trip to see some of the large science projects in our area. The first stop was the B Reactor at Hanford. In the picture - below at left - our class is standing in front of the reactor pile. The next stop was LIGO. The picture below at right has us posing in front of one of the interferometer arms.
The month of May has seen two milestones involving physics at Walla Walla University.
The physics club is once again active. The first event (the left side of the picture) was food and a video on Richard Feynman.
The old sofa in the seminar room finally got too old and was replaced. Alina managed to get the picture on the right as the sofa headed out of the building. A new sofa is already in place.
This month we have been purchasing new equipment for the introductory classes (Principles of Physics, General Physics, Conceptual Physics, and Physical Science). In the picture, the blue tube and the open speaker are used to study resonance in sound waves. These new tubes are much easier to use since they have the scale on them and have an option for open verses closed tubes.
The piece of glass in the bottom center of the picture is used to study Snell's Law and replaces the much smaller and chipping pieces of glass that we have used for many years.
The blue meter at the lower left is a new galvanometer which has three settings to allow us to measure two different levels of current and one voltage.
All of these new parts have been purchased with 12 sets of each so the full lab can use them. Some of the parts arrived in time that they were used this month. Next year will be the first time that all the labs will get to use them.
At the quarter comes to an end, we have gotten to play with some fun things. Liquid nitrogen is used in several labs to demonstrate how superconductors work. Once that is demonstrated, some of the nitrogen gets used for less scientific purposes. Follow this link to see a frozen gummy bear land on the floor.
One application for nanoparticles is in a material called ferrofluid. It is made up of small iron particles and a heavy oil. As shown in the picture below, the fluid will change shape in the presence of a magnetic field. A good lab using this material ends up with a small mess to clean up. The lab this year ended with two students a bit covered in their work. Their picture has been removed to protect the spattered.
In Experimental Physics lab this quarter, we made a robot. In the picture at left, two microphones are glued to the end of the wooden sticks. Those microphones are the ears or our robot. A small circuit just visible at the top of the picture, processes the signals slightly to get rid of low frequencies and increase the gain. The computer program listens to the difference in sound and moves the stepper motor. A laser is mounted on the motor and given a strong enough signal should eventually point toward the sound. Some of the lab groups had better results that others.
This quarter in Introduction to Nanotechnology lab we are building a scanning tunneling microscope as we usually do for this course. During the first week of the quarter, we built the physical system. We are using a disc piezo as our motor. The detailed build directions are available at https://www.wallawalla.edu/academics/areas-of-study/physics/faculty/ekkens-research/studentstm/ The record resolution from 2016 is 5.5 nm. That record may not last until the end of the month.
As we come to the end of this quarter, we are also coming to the end of our first-ever astrophysics class. Dr. Campbell has conducted eight students through the mysteries of the universe in this quarter long class. The course only requires Principles of Physics before hand so students from many majors can take it.
In Modern Physics, we get to talk about the new fun things in physics for the last 100 years or so. Part of that discussion focuses on tunneling. We work out the math for tunneling probability but building the scanning tunneling microscope is put off until Nanotechnology Lab. For the lab in Modern Physics, we start with a simpler step and build a local probe device. Normally it would be a microscope but our scan area was about 1cm on a side so that makes this a macroscope.
We used speakers as the motors and felt for the presence of the surface by detecting a closed circuit. The final setup is shown in the left picture and the result of scanning a coin is shown in the right picture. There is still a lot of room for improvement - the distortion in the image is the result of making an easy scanning system instead of an accurate scanning system.
As we start off the new school year, Modern Physics is offered for junior physics majors. One of the experiments that we do is Bragg Scattering using microwaves. In this picture, the microwaves are coming from the transmitter on the left, scattering from the silver tubes in the center, and then being detected by the receiver on the right.
3D printers are starting to change the way we do experiments at Walla Walla University. Each fall we do a lab where we study the photoelectric effect using light emitting diodes. In the past we have put the light detector and the LED in a cardboard box to keep out the light. This fall, the cardboard box has been replaced with a 3D printed plastic box. In the picture, the cap is off the box on the left so the LED and detector can be seen. The box on the right is closed so that no light gets into the detector.
A number of us from the university spent some of the day in the John Day area to view the eclipse. The pictures were taking using a normal Panasonic camera. The camera was not able to capture the color very well.
School is out. Graduation has passed. The next thing to focus on is summer camps. 19 campers joined the Village Church Science camp for the first week. One of the first stops of the week was in the physics lab to learn about experimental science. We talked about motion of particles and how that works for sound. The campers enjoyed playing with waves on strings and making noise using a speaker and function generator. Then we broadened the focus and talked about how the particles of light work.
As the weather is getting warm, more labs can be done outside. In the picture, Dr. Campbell is explaining the index of refraction in terms of speed on rough terrain. The Principles of Physics students are taking the place of photons and their marching speed is considerably slow than 300,000,000 m/s.
As the quarter comes to a close, lots of activities are going on. In the Physical Electronics lab, the students have completed pnp transistors. For the last lab of the quarter we looked at them using several different microscopes. In the picture at the left, the doped areas are visible as the shiny colored areas. The boundaries between the doping are made mechanically and are visible as the gouges in the surface.
Spring Quarter means the material we are covering in all the 200-level classes is about light. One of the labs we do is to build a simple telescope out of two lenses. The picture shows the magnified (and inverted) tree outside the lab window. Our lenses allow a magnification of about six times.
Our final project in Experimental Physics this quarter was to find vibrations on our vacuum system. The vacuum is created by a pump which shakes the entire system. It would be nice to reduce the vibration so we took measurements from the fan, the motor, and the compressor to see which one is responsible for the largest shaking. In the picture, the amplitude of each frequency is plotted from the motor. The peak at 29 Hz is the highest so a new motor would help us reduce the noise.
In Experimental Physics we are making a motor coupling. We have made the part two different ways to see the differences (strengths and weaknesses) in the manufacturing processes. On the left of the picture are the parts that were printed using PLA on our 3D printer. On the right are the equivalent pieces that we machined from aluminum using a lathe, end mill, and drill press.
From this process, we found that the machined parts took longer to make but had better tolerances so we used them for the motor coupling.
In Experimental Physics this quarter, we are learning about electronic components. One lab was spent learning to design circuits and building a circuit board using household items. We also sent the design for each circuit board out to a company to have professional boards made. In the picture, four of the boards are shown. Each board does the same thing but since each student designed their own board, the layout is a little different.
This December has brought more snow to the Walla Walla valley than usual. In the picture, our solar panels are under several inches of snow. This has not been the best month for solar power generation.
Every two years we set aside a department chapel to highlight student research. This November 1 was that meeting. Three physics majors (Lam, Alina, and Devin) presented their research from the last year or two. We had an excellent turnout and enjoyed the breadth of research projects that students are able to do here at WWU and at our associated schools.
In the Modern Physics lab this quarter, our first experiment was to measure the speed of light using a laser and and light detector. Initially we build the detector circuit on a breadboard. That wasn't stable enough so Dr. Ekkens designed the PCB shown in the upper left of the picture. Further work in the lab suggested that the circuit could be simplified to the circuit shown on the upper right. The bare board is shown at the lower right. Results from this design are very good with the calculated speed of light being 299,000,000 m/s with an uncertainty of 11,000,000 m/s.
The first Monday of the school year was also the first use of the observatory for this year. We had about 20 physics majors and friends look at Mars and Saturn through the small telescopes and a globular cluster through the large telescope.
This summer the physics department purchased a 3d printer kit. Over the summer, the kit was built up and the first parts have been printed. In the picture, the second piece ever is being printed. This piece is a sample stage for the PVC scanning tunneling microscope. If the piece gets used, the microscope title will need to change to PVC + PLA. The 3d printer will be used most often in the Experimental Physics classes.
Through this past spring and into the summer, we have been working on building up new equipment. During the spring quarter, one of the physics majors started working on two new electro-magnets. He cut the pieces of steel into the right lengths. During the summer, the first magnet was finished with help from Dr. Ekkens. This magnet has been built using a slightly different process than the previous ones - the pieces of steel have been welding together instead of being bolted together. Results so far look promising with over 1000 Gauss being generated at 3 amps. The second magnet has not been completed yet so physics majors during the 2016-2017 school year will work on it.
Graduation has come and gone. The summer session has started and General Physics students are taking classes each morning. The physics department helps with science camps during the summer. This summer, we hosted students on two days. In the picture at the left, the campers are looking through a microscope to see what the display on their cell phone looks like. They also played with lenses and built several circuits.
Graduation is here. Pictured are Dr. Liebrand at the left, Dr. Ekkens at the right, and the entire physics graduating class in the middle. In fairness, four students graduated the previous year which is higher that average for our department.