March 2018: Liquid Nitrogen; Ferrofluids.
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.
February 2018: Laser Robot
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.
January 2018: Nanotechnology and STMs
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.
December 2017: Astrophysics
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.
November 2017: Local Probe Macroscope
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.
October 2017: Bragg Scattering
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.
September 2017: 3D Printed Parts
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.
August 21, 2017: Eclipse Day
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.
June 2017: Science Camps
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.
May 2017: Wave Motion with People
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.
May 2017: pnp Junctions
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.
April 2017: Telescopes and Microscopes
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.
March 2017: Vibration Hunting
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.
February 2017: Making Parts
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.
January 2017: Circuit Boards
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.
December 2016: Winter & Solar
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.
November 2016: Student Research
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.
October 2016: Speed of Light
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.
September 2016: Using the Observatory
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.
August 2016: 3D Printer
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.
July 2016: Building Equipment
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.
June 2016: Summer Camp
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.
June 2016: Graduation
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.
May 2016: Semiconductor Labs
As we come to the end of the quarter, the Physical Electronics laboratory does a lab were we look at several commercially available semiconductor. In the picture at the right, one of the lab groups is using the light-based microscope to get pictures of an operational amplifier. They are measuring the width of the traces that make up the activity elements of the chip.
April 2016: Building pn Junctions
In the Physical Electronics course, the students are building a pn junction (a diode). So far we have used the tube oven to heat the silicon wafer to over 1000 C to diffuse another material into the wafer. During lab in the coming weeks, we will add metal contacts and test the diode. In the picture at the left, the tube oven is nice and toasty.
March 2016: Liquid Nitrogen and LEDs
The last laboratory of the quarter for the nanotechnology class used liquid nitrogen. In the picture here, a green LED is submerged into a bath of liquid nitrogen. As it cools, the color shifts to yellow. Once the LED is removed and warms up, the color returns to the original wavelength.
February 2016: Gravitational Waves
LIGO announced their discovery of gravitational waves at a press conference in Washington DC this month. At the LIGO Hanford site, a special event was hosted to discuss the data and tour the site. Several of us associated with the Physics Department were able to attend the event. In the picture below, we are listening to the sound two black holes make as they collide.
February 2016: Using the STM
Week 5 in nanotechnology: In the first week of lab we built the scanning head for the scanning tunneling microscope, in the second week of lab we worked on the electronics and connections to the computer, and in the fourth week of lab we tested it all out. Today we starting looking a different samples included a DVD disk, copper circuit boards, and graphite. In the picture below, the leader board from the day is shown with insets of the various groups working with their microscopes. A definite spirit of competition was felt during the lab. The previous record resolution of 16 nm is history - broken by three of the four lab groups. Group four was going for the ultimate prize - trying to image graphite. It is very difficult to do in a room full of people and they didn't get today. Maybe later . . .