Mentorship - In Memory of Prof. Ernst Deiter-Schmitter

Prof. Schmitter (far right)

Prof. Schmitter (far right)

I had been thinking about a blog post on the importance of being a mentor in an academic setting (or any other setting really). Unfortunately I lost one of my early mentors and wanted to write a short story to show the impact that being a mentor can have.

When I was in high-school I was fascinated by tornadoes and electric fields. I still am. I decided that I wanted to research the connection, so I began to read lots of literature on the subject (my first exposure to peer-reviewed papers) and looking for places I could contribute. I landed on the Yahoo Groups page of a group dedicated to ULF/VLF studies. After asking some very basic questions, I ended up chatting with Prof. Schmitter through e-mail. After weeks of communication and beginning to design an instrument, he inquired as to which institution I was at. I replied that I was a high school student, expecting to never hear back from him. The response was exactly the opposite. Ernst re-doubled his efforts to help me undertake a project.

This effort wasn't to check off a box on a funding agency outreach goal sheet, but it was a true excitement to help a student learn. I was very excited about the whole thing! We did design an instrument that I constructed at my home in Arkansas. Some friends and I took it to the field and collected data. After returning, I sent Ernst the data and he suggested we write a publication.

Having never written anything more than a detailed physics lab report before, this was an incredible learning experience.  We worked the paper over a few times and had a couple of Skype calls about it. He submitted the paper, absorbing the cost of publication. That was my first scientific article.

Did I mention that he was a professor in Germany? We never met in person. I had seen his recent publications come out and kept meaning to email and update him that I had again been working in electrostatics. I didn't get it done. It had been too many years since we talked. I do have a new instrument that we designed some years ago that still needs to be built and tested, but it will surely be many times more difficult now.

What is the lesson in this other than contacting people before you can't anymore? It's is that you never know who you will inspire. Without pushes from Prof. Schmitter I probably wouldn't have finished the project and published anything. That publication helped me get a foot in the door of the research field. That's how I found out I wanted to do research as a career (thanks to several other amazing mentors). The lesson is that taking the time to talk to interested students is one way to have a lasting impact, even after your time.

I consider myself incredibly lucky to have had as many amazing mentors and teachers at every stage of my life. I'm in much deeper service debt than I can ever hope to pay off in one lifetime. I want to thank everyone reading this for encouraging me through direct contact or just by supporting this blog with your readership. This post serves to show that everyone of you make a difference in the lives of others everyday.

* I looked back through our emails had we had nearly 200 pages of email exchange before I had finished my first year of college. That's a lot of information!

Knowing the Fundamentals

phdcomics.com

phdcomics.com

Ok, I've been sitting on this topic for awhile, but I was recently inspired to revive this post after being asked some very general questions by a tour group that came through the lab. Next time we'll be back to doing some data collection and analysis. Maybe gravity tide measurements? Anyhow, on with the topic of the day: knowing the fundamentals.

On a (now old) episode of the podcast Technical Difficulties, Gabe Weatherhead (@macdrifter) was chatting with Brett Terpstra (@ttscoff) and Rob Trew (@complexpoint). The show was mostly about how everyone got started writing computer code and some tool suggestions. One line made me stop on my walk home to type it into my reminders to write this post.

Rob quoted a line from the Windows 95 API Manual (a programming interface manual for the non-programmers out there). It said "The nature of an expert is not someone who knows all the details, it's someone who understands the fundamentals really well." Rob points out that therein lies the key to problem solving. This statement really resonated with me when I looked back on problems that I've encountered in the past, both scientific and technological.

We often think of an expert as someone that is in the top few percent of the knowledge leaders in their field. Experts should know all of the details of their subject, including the latest "bleeding edge" research right? While many experts do stay up to date, I began re-examining the people that I considered to be experts.

The professor may be the ideal example of this. While academics often get the connotation of the aloof and socially insulated genius, it's really not true. (In fact, our academic heroes are just people too, listen to the latest Nerds on Draft for that side story.) Professors have to teach the same material over and over again during their career. Sure, they should be pushing the frontiers of their field within their research group, but that's not what should be done in the education potion of the career. When you teach something, you end up deeply learning it yourself. In fact, that is part of the value in teaching! Be continually re-iterating the fundamentals to ourselves, we can stay primed to approach a new problem with a honed set of tools.

What could these fundamentals be? Well, that depends on your work. Maybe it is knowing the basics of programming or how to do basic chemical balance/thermodynamics calculations. Maybe it is knowing the fundamental operation of the product that you sell, or knowing the backstory to a concept you are helping someone with (such as the history of a topic).

I can't count the number of times that I've been trying to figure out a solution to a problem or how to build something when, after hours of no progress, something will make me start again. This time I look from a fundamentals viewpoint and can generally see a way to a solution or at least enough of the way to be able to ask an intelligent question.

Ideally, we are prepared for this way of problem solving by getting the basics of many fields during our undergraduate careers. Unfortunately that doesn't always happen. We have all sat in a math class, economics class, etc when the professor goes deep into a subject that they adore and leaves us in the dust. Another common occurrence is that the application of the fundamentals is not shown or sometimes not even implied. Not that students should be guided by the hand to the solution, but sometimes a firm nudge is necessary. I didn't necessarily appreciate this early in my undergraduate career, but later became a mass consumer of basic knowledge.

Next time you are on Amazon or in the library, browse over to a section with a topic of interest and pick up an introductory book. Read some sections, try some problems, and you'll be amazed at the other angles you can suddenly see as avenues of attack to a problem. You can even pickup some of your old text books and remind yourself of the fundamentals that all too often slip from our minds with time.

Measuring the Speed of Sound

In the past on the "Don't Panic Geocast" we've talked about the speed of sound varying with temperature and how that can cause sound waves to bend. This phenomena, known as refraction, can result in all kinds of weird events, like being able to hear things from very far away when a thermal inversion is present in the atmosphere.

As I was researching some for that episode, I found that the standard formula for the speed of sound with temperature is a nice simple linear function over the ranges we care about. True, pressure and humidity can factor in there, but for simplicity, let's consider the largest factor... Temperature.

Formula for the speed of sound in dry air in m/s. Temperature is Celsius.

Formula for the speed of sound in dry air in m/s. Temperature is Celsius.

The formula above means that the speed of sound varies with temperature by 0.6 meters/second for every degree celsius of temperature change. That's about 2 ft/s for those of us more used to imperial units. A change that large should be pretty easy to see, right? This experiment and post were born from that statement.

To measure the speed of sound, I had several ideas. I could generate a short burst of noise and using an oscilloscope time how long it took to get to a microphone. That would require me to manually make the measurements, which probably means not a ton of data points since I'd have to either use the refrigerator to get a temperature difference or sit outside for a day. Neither of those were appealing. I ended up remembering some hardware that I had sitting around from the ultrasonic cave profiler.

The part of interest is the ultrasonic ranger. This little device (an SRF05) sends out a packet of ultrasonic pings and listens for their return. The device lets us know how long this takes by toggling an output from a digital 1 to digital 0. I already had the code to run this sensor, so I was half way there! The next thing I needed was a way to log the data. I didn't want to leave the door to the outside open to get power out there for the setup. I ended up using an SD card logger on top of the Arduino that was keeping track of the travel time.

Finally, we needed a target to range. Luckily, this was easy to do with some wood sticks, hot glue, and a plexiglass base plate. I glued the target to the base 260mm from where the pinger was mounted. After a couple of quick tests, I had verified that the setup was working! Adding a temperature and humidity sensor to the breadboard gave us everything we needed. Time to collect some data!

setup

Schematic of sound packets being transmitted and reflected. Really these are spherical wave-fronts, but the illustration is much cleaner this way!

Luckily, we've had pretty wide temperature swings during the day here in Pennsylvania lately. Using a decent sized 12V battery and voltage converter I could get days of run time on a single charge. To get the best data possible, I averaged many travel times per sample. This took less than a minute to do, which is fine since temperature isn't changing that rapidly.

The complete setup in a tub ready to collect data outside.

The complete setup in a tub ready to collect data outside.

Now that a simple apparatus was complete, I placed it in a Rubbermaid tub to keep any stray precipitation (or the rodents) from damaging things. The data was stored in a text file containing two-way travel time to/from the target in microseconds, device estimated distance to target, and the temperature/humidity readings. I collected several days worth of data, each time slightly improving my recording setup to get the cleanest data. I had problems with days where the temperature varied very fast and it appears to have introduced noise, some days there was direct sunlight (a rare thing in the PA winters) that caused very high temperatures and convection in the tub. Finally, on the last day of my experiment, I got a nice data set. It was a day with slowly varying temperatures and mostly cloudy. I trimmed the ends of the data so things were equilibrated and got some decent results!

Temp_RH

If we plot the temperature and the speed of sound against each other, we see what looks like a line! The steps are a result of being at the smallest increments in time that our system can sense. A better sensor could solve this, but for a rough estimate it turns out to be fine. Finding the best fit through this should tell us how well our measurements match the accepted formula. The slope of the line represents the rate of change of the speed with temperature (this should sound familiar to those calc. students out there), and the intercept represents the speed of sound at zero degrees.

Temp_Speed

 

We got the rate of change dead on! In fact we are within a few percent of the accepted value. The y-intercept is off by about 6 m/s, but I think that is a systematic offset due to a delay in the way the sensor is read. We could back that out, but maybe that is another topic for another time, or maybe we'll try this again with a different sensor. Please leave any comments or questions below!

Going to the Science Fair

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Explaining doppler RADAR with an actual demo!

 

This past week I got to relive some of my favorite days of primary education: the science fair!  A local elementary school was hosting their annual science fair and had asked the department to provide some demonstrations for the parents and students to see. I immediately volunteered our lab group and began to gather up the required materials. Some of the setups were made years ago by my advisor. I also developed a few and improved upon others here and there. I thought it would be fun to share the experience with you.

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The line-up of demonstrations setup as the science fair was getting started.

 

At some point, we should probably have a post or two about each of these demonstrations, but today we'll look at pictures and talk about the general feedback I received. First, off we had four demonstrations including the earthquake cycle, how rocks are like springs, seismometers, and Doppler RADAR. I made an 11x17" poster for each demo in Adobe Illustrator using a cartoon technique that one of our professors here shared with me.

Screenshot 2015-02-28 14.41.01

Here is an example poster from one of the demonstrations.

 

For scientists, communicating with the public can be difficult. It's easy for us to get holed up in our little niche of work and forget that talking about a topic like power spectra isn't everyday to pretty much everyone. Outreach events like this present a great opportunity to work on those skills! This particular event was especially challenging for me because the children were K-5, much younger than I usually talk to. With high school students you can maybe talk about the frequency of a wave and not get too many lost looks, but not with grade-schoolers!

The other difficulty was adapting what are deep topics (each demo is an entire field of research, or several) to the short attention span we had to work with. Elementary school teachers are masters of this and I would love to get some ideas from them on how to work with the younger minds. I spent most of my time talking about the Doppler effect with the RADAR (it's the topic my lab mates were least comfortable with since we don't deal with RADAR at work generally). By the end of the science fair, I had an explanation down that involved asking the kids to wave their hand slowly and quickly in front of the RADAR and listen to how the pitch of the output changed. Comparing that to the classic example of the pitch bending of a passing fire truck siren seemed to work pretty well. I had a "waterfall" spectra display that showed the measured velocity with time, but other than trying to get the line to go higher than their friends, it didn't get much science across (though lots of healthy competition and physical exercise was encouraged).

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An excited student jumps up and down to see herself on a geophone display.

 

In the past, I've pointed out the value of being an "expert generalist". All of us were tested in any possible facet of science by questions from the kids and their parents. I ended up discussing gravitational sling-shot effects on space probes with a student and his parents who were incredibly interested in spaceflight. I also got quizzed about why the snow forecasts had been so bad lately, when the next big earthquake would be, and a myriad of other questions. Before talking to any public group, it's also good to make sure you are relatively up-to-date on current events, general theory, and are ready to critically think about questions that sound deceptively simple!

The last point I want to bring up today is the idea of comparisons. These are numbers that one of my committee members likes to say he "carries around in his shirt pocket." These are numbers that let us, as scientists, relate to others that are non-specialists and give us some physical attachment to a measurement.  What do I mean? Let's say that I tell you that tectonic plates move anywhere from 2-15 cm/year. Great, first, since we are in the U.S.A., everyone will hold out their fingers to try to get an idea of what this means in imperial units.... not quite 1-6 in/year. That's better, but a year is a long time and I can't really visualize moving that slowly since nothing I'm used to seeing everyday is that slow... or is it? Turns out that fingernails, on average, grow 3.6 cm/year and hair grows about 15 cm/year. Close enough! In Earth science we have lots of approximate numbers, so these tiny differences are not really that bad. Now let's revise our statement to the kids to say: "The Earth is made of big blocks of rock called plates. These move around at about the speed your finger nails or hair grow!" Now it is something that anyone can relate to, and next time they clip their nails or get a hair cut, they just might remember something about plate tectonics! It's not about having exact figures in the minds of everyone, it's about providing a hand-hold that anybody can relate to! This deserves a post to itself though.

That's all for now, but I'd love to hear back from anyone who has elementary education experience or has their own "shirt pocket numbers."

 

Raindrops Keep Falling on my Radar - Part 2

Last time we looked at the raindrop fall speed of raindrops during a thunderstorm and compared the radar reflected power to my observations of the storm moving through State College. Today, thanks to Yvette Richardson and Bill Syrett from the Penn State Meteorology Department, we can compare the radar returns to actual weather station data. They were able to provide data from a weather station on top of the meteorology building on campus, about 3 miles from where my radar was located.

We expect more power to be returned to the radar during periods of heavy rain, so the main variable of interest is the rain rate. We'll plot up a couple of other meteorological variables just for fun as well. The weather station recorded observations every minute. I had to venture my best guess at the units based on their values. The rain rate values are low. Another station that I don't have the time-series for reported a maximum rain rate of 0.26 in/hr. Either way, let's examine the relative changes.

rain_wx_data_graph

 

Looking at the plot we can see that our prediction of higher rain rate equaling more reflected power holds. Unfortunately, the weather station didn't record precipitation rate with very fine resolution, so we really can only match the peak rain rate with the peak reflected power. The vertical red line marks the time of a weather service doppler radar screenshot we looked at in the last post that was right before the heaviest rain arrived. We also observe the higher wind speeds with the gust front ahead of the storm. As the storm passed over we saw decreasing pressures as well. The temperature and humidity aren't shown because they really weren't that interesting.

Now that we've verified our hypothesis (roughly anyway) about precipitation rate and radar return, we are ready to look at different types of reflectors. Next time, we will look at radar data collected during a snow storm for return intensity and the fall speed of snow flakes. That speed can be compared with video of falling snow for verification. Stay tuned!

Raindrops Keep Falling on my Radar - Part 1

What's the most complicated way to say it's raining? Well, if you know me, you know it will involve electronics, sensors, and signal processing! This post was originally going to compare the fall velocity for rain, sleet, and snow. Unfortunately, I haven't been lucky enough to be home to run my radar when it was snowing. It will happen this winter, but we'll start looking at some data now. Want to review radar before we get started? We have already talked about looking at the doppler signature of cars and got a tour of a mobile weather radar.

Back in October we had a couple of squall lines come through. On the 3rd, there was a significant event with two lines of storms. I had just been experimenting with measuring rainfall velocity with the modified X-band radar, so I decided to try another experiment. I put the radar unit in a trashcan and covered it with plastic bags. Then I sat it outside on our balcony and recorded for about 2.5 hours.

Testing the radar setup before the rain with some passing cars as targets.

Testing the radar setup before the rain with some passing cars as targets.

There is a radar in there! My make-shift rain proof radome. The only problem was a slight heat buildup after several hours of continuous operation.

There is a radar in there! My make-shift rain proof radome. The only problem was a slight heat buildup after several hours of continuous operation.

Not only do we get the doppler shift (i.e. velocity of the raindrops), but we get the reflected power. I'm not going to worry about calibrating this, but we can confidently say that the more (or larger) raindrops that are in the field of view of the radar, the more power will be reflected back.

First, let's look at a screenshot of the local weather service radar. You can see my location (blue cross) right in front of the second line of showers. At this point we had already experienced one period of heavy rain and were about to experience another that would gradually taper off into a very light shower. This was one of the nicer systems that came through our area this fall.

A capture of our local weather radar, my location is the blue cross directly ahead of the storm.

A capture of our local weather radar, my location is the blue cross directly ahead of the storm.

Now if we look at the returned power to the radar over time, we can extract some information. First off, I grouped the data into 30-second bins, so we calculate the average returned power twice per minute. Because of some 32-bit funny business in the computations, I just took the absolute value of the signal from the radar mixer, binned it, and averaged.

Reflected power received by the radar over time. The vertical red line is the time that the radar screen shot above was taken.

Reflected power received by the radar over time. The vertical red line is the time that the radar screen shot above was taken. We can see the arrival and tapering off of the storms.

From this chart we can clearly see the two lines of storms that came over my location. We also see lots of little variations in the reflected power. To me the rain-rate seemed pretty constant. My best guess is that we are looking at skewing of the data due to wind. This could be solved with a different type of radar, which I do plan to build, but that doesn't help this situation.

Let's look at what inspired this in the first place, the rainfall velocity. From a chart of terminal velocities, we can see that we expect to get drops falling between 4.03-7.57 m/s for moderate rain and 4.64-8.83 m/s for heavy rain. Taking a 5 minute chunk of data starting at 60 minutes into the data (during high reflectivity on the chart above), we can compute the doppler frequency content of the signal. Doing so results in the plot below, with the velocity ranges above shaded.

psd_velocity

Doppler frequency content of 5-minutes of data starting at 60 minutes into recording. The blue box shows doppler frequencies corresponding to moderate rain, and the red box corresponding to heavy rain.

Based on what I see above, I'd say that we fall right in line with the 0.25"-1" rain/hour data bracket! There is also the broad peak down at just under 100 Hz. This is pretty slow (about 1 m/s). What could it be? I'm not positive, but my best guess is rain splattering and rebounding off the top of my flat radar cap. I'm open to other suggestions though. Maybe part of this could be rain falling of the eve of the building in the edge of the radar view? The intensity seems rather high though. (It was also suggested that this could be a filter or instrument response artifact. Sounds like a clear air calibration may help.)

So, what's next? We'll take some clear-air calibration data and the use data from a Penn State weather station to see what the rain rate actually was and what the winds were doing. Maybe we can get a rain-rate calibration for this radar from our data. See you then!

Thank you to Chuck Ammon for discussions on these data!

 

Don't Panic Geocast - Now on Your Radio!

DSCF4046

I would like to announce the official release of the first episode of the "Don't Panic Geocast!" This is something that has been in the works since earlier this summer. Each week Shannon Dulin and I will be discussing geoscience (geology, meteorology, etc) and technology. Please be sure to add us to your feeds and checkout our first show!

Sensors, Sensors Everywhere!

This year at the fall meeting of the American Geophysical Union, I presented an education abstract in addition to my normal science content. In this talk, I wanted to raise the awareness of how easy it is to work with electronics and collect geoscience relevant data. This post is here to provide anyone that was at the talk, or anyone interested, with the content, links, and resources!

Sensors and microcontrollers and coming down in price thanks to mass production and advances in process technology. This means that it is now incredibly cheap to collect both education and research grade data. Combine this with the emergence of the "Internet of Things" (IoT), and it makes an ideal setup for educators and scientists. To demonstrate this, we setup a small three-axis magnetometer to measure the Earth's magnetic field and connected it to the internet through data.sparkfun.com. I really think that involving students in the data collection process is important. Not only do they realize that instruments aren't black boxes, that errors are real, and that data is messy, but they become attached to the data. When a student collects the data themselves, they are much more likely to explore and be involved with it than if the instructor hands them a "pre-built" data set.

For more information, watch the 5-minute talk (screencast below) and checkout the links is the resources section. As always, email, comments, etc are welcome and encouraged!

Resources

Talk Relevant Links

- Slides from the talk
- This blog! I post lots of electronics/data/science projects throughout the year.
- Raspberry Pi In The Sky
- Kicksat Project
- Weather Underground PWS Network
- uRADMonitor
- Our IoT magnetometer data stream
- Python Notebooks
- GitHub repository for the 3D Compass demo
- AGU Pop-Up Session Blog

Parts Suppliers

- Adafruit
- Sparkfun
- Digikey
- Element14

Assorted Microcontrollers/Computers

- Beagle Bone
- Raspberry Pi
- Arduino
- Propeller
- MBed
- Edison
- MSP430
- Light Blue Bean

General

- Thingiverse 3D printing repository
- Maker blogs from places like Hackaday, MAKE, Adafruit, Sparkfun, etc

How I Design a Talk

This year I'm co-chairing a session at the American Geophysical Union meeting called "Teaching and Career Challenges in Geoscience." We have been maintaining a blog for the session at keepinggeologyalive.blogspot.com. I wrote a post that I wanted to cross-post here in hopes that you too may find a few tips to help with the next presentation you need to give.

Hello everyone! While I was preparing my talk, I thought I would share my process in the hope that maybe someone will find a useful nugget or two. There are lots of great resources out there. Books like Pitch PerfectTalk Like TED, and the MacSparky Presentations Field Guide are great places to start. With AGU only a couple of weeks away, I wanted to highlight a few ideas on presentation planning.First, close PowerPoint or Keynote. The presentation software is not the place to start preparing a presentation. I like to sit down in a comfortable spot with a stack of index cards and a mug of coffee. While I love technology as a tool, it's just too early. I write out one major thought on the top of each card and put supporting material on as a list. For a short talk, like the pop-ups, this is just a few cards, but I've had stacks over 2 cm high for longer talks. I put everything I might want to bring up on these, pruning the content comes later.  After my cards are made, I lay them out on a big table (or the floor) and play with the ordering. I'll ad-lib sections of a fake talk and see if two thoughts can flow smoothly into each other. Once I'm happy with the general layout, then I'm ready to move on.

After playing with index cards, I'll let technology in. I like using OmniOutliner to help here. I put my index cards into a digital outline. Lots of people start here, which is fine. I like starting on paper because I can sketch things out and feel less constrained. Index cards also don't have email notifications that interrupt your thinking. In OmniOutliner, I break out my thoughts into short bullets. I can drag in content such as a photo of a sketch I think may turn into a graphic, sound bytes of an idea, or quotes I want to include.

Now it is time to decide on supporting graphics. I have an idea of what I'm going to say, so what visual aides will help tell the story? Your slides are not an outline and are not meant to guide you through the content. You and the slides together will guide an audience through your work in a logical way. Graphics can be photos, graphs of data, schematic diagrams, anything! Personally, I like make my graphics using an assortment of applications like PythonAdobe Illustrator, or OmniGraffle. Making graphics is a whole other series of books that you could dive into, including the great books by Nathan Yau: Visualize This and Data Points.

Finally, it's time to make your slides. I follow the Michael Alley approach of a slide with a (nearly) complete sentence at the top, followed by graphics. The fewer things that the audience has to read, the closer they will be listening to what you have to say. If you need to document your material to hand-out, produce a small one or two page text document with the necessary graphics (an idea from Edward Tufte). Again, the slides should not be the presentation, but support for it.  If you are stuck for ideas on slide design, head over to Garr Reynold's blog Presentation Zen. Garr has some great examples, as well as his own books.

My last tip regards the ends of your presentation. The beginning and the ending are incredibly important. The beginning is where you gain or loose the audience, and the end is where you make sure that their time was well spent. Nail these. I don't script presentations, it sounds too robotic, but the first and last 30 seconds are written down and well thought out.

I can't wait to hear what everyone has to share and I hope that some of these tips and resources are useful in your preparation!

Breaking the Wishbone - How to Win

The folks over at Michigan Engineering did some modeling, 3D scanning, and experimentation to tell us how to win at the age-old Thanksgiving game of breaking the wishbone. According to the folks over at aaepa.com, the tradition is much older than Thanksgiving, dating back over 2400 years to cultures that believed that birds were capable of telling us the future. There is even suggestion that the phrase "getting a lucky break" can be traced to this tradition.  If you want to win, watch the 76 second video below and remember: choke up, stay stationary, and pick the thick side.