Wednesday, January 20, 2016

Geology Lab Lessons: My first semester back as TA

With the new year comes a new semester, and more TA duties. First off, re-organizing all the mineral jars again:


The strongest force in the universe for randomly re-organizing minerals is a semester of geology students.

I've also been looking back on the previous semester to see how I could improve the lab lessons and my own teaching styles. The teaching evaluations I got back were very useful for me to see what worked and what didn't. The following are the lessons I learned from my first semester back as a lab TA.

  • Enthusiasm, enthusiasm, enthusiasm. The vast majority of students in my labs were not geology or environmental science majors, so interest in the subject was not something they brought to day one of class [yes, geology is awesome, you don't have to tell me that]. It's safe to assume most of the students show up with a neutral stance (at best) of the material. I think one of the most important things I brought to class was a love of the subject. For me, it's fun to get excited about geology. Looking back as a student, the teachers and professors I most enjoyed having class with were those that were really into their subject. sure, I can dryly cram as much information into their minds as I can (I don't like this approach to learning), or I can structure the lab in a way that makes it more enjoyable, in which case they'd want to go out on their own to learn more (this was my approach, and it seemed to work very well).

  • Be a person. You are not a machine. You're more than just a repository of knowledge tasked with shoveling as much as possible into their heads. The students responded more positively to the class when I incorporated my own background and experiences into the lessons. We're studying rocks? I'll bring in my favorite one, and tell them why. Talking about topo maps? I'll tell them the story of how useful they were in the Black Hills. Talking about hydrology? I get to talk about my time as a hydrologist, protecting drinking water. Anything to make the lessons more real and relevant seemed to work.

  • Write a syllabus that protects you. I was lucky to have a good group of students, but there was one problematic student who would miss exams and blame me for not allowing them to retake it without an excuse. I was willing to accommodate for good reason, but their complaints turned to personal attacks, and at that point I stood behind my syllabus.

  • Work harder than they do and stay positive. Never, never give them the impression that you are lazy or do not care about what you are doing. Know the lessons, and don't get caught by surprise - have an intimate knowledge of your business. Respond to emails quickly. Bring in extra material to demonstrate a hard to understand topic. Put in more effort to the class than they do. I consider this a "lead by example" approach to education. 

  • Strive for a positive learning atmosphere. Be friendly and approachable. Encourage questions, even if it might sidetrack the lesson. It's entirely possible to be professional while also joking around (my specialty is puns). Learning is fun!

Monday, January 11, 2016

Mini-drone Photogrammetry Test

Behold, my new Parrot Rolling Spider Minidrone:


The Minidrone takes its new rightful place next to the other little aircraft. Good grad office flair.

This neat little bugger has some built-in sensors and instruments which allows for some very stable flight. Combining the use of a pressure altimeter, sonic altimeter, and downward facing camera, it can hover essentially hands-free. The downward facing camera can also take meh-resolution photos, which I thought had some potential for a fun photogrammetry demo, instead of the not-so-subtly spying on my roommates that it's mostly been used for so far.


Incoming foot! Warning! Warning!


I wanted to calculate the height of something using photogrammetric principles. This is possible using geometry; the image of an object is distorted based on how far away from the center of the photo it is (the farther an object is away from the center of the photograph, or Principle Point, the greater the apparent displacement between the top and bottom of the object. Directly overhead, there is no displacement, so you can only see the top).

Using a single photograph to measure the height of an object, from "Remote Sensing of the Environment: An Earth Resource Perspective, Second Edition, by J. R. Jensen).


In the grad lab, I set up a small box, simulating a building, and had the drone fly over it (at eye-level with myself) and take a photo, simulating a low-flying aircraft. 


Building. Not to scale.

Below is the resulting photo. Notice how the box is distorted, and the distortion radiates away from the center of the photograph. Also, the distortion is greater with greater distance from the centerpoint.


Raw aerial photo from the minidrone of the study area from a breathtaking altitude of 5.5 feet.


Next, the math! Using the equation above, the height (h) of the box is equal to the lateral displacement of the top and bottom of the box (d) times how high up the photograph was taken (H) divided by the lateral distance from the center of the photograph (principle point) to the top of the box (r). 

h = (dH)/r

I was able to try this for two spots, as more than one edge of the box was in the photograph.


Aerial photo with annotations. Altitude: 5.5 feet.

Using a ruler and my computer screen, I got the following values:
r1 = 18.0 mm
d1 = 4.5 mm

r2 = 13.2 mm
d2 = 3.2 mm

H = 5.5 feet (my height)

This results in calculated box heights (h) of 1.38 feet and 1.33 feet. Let's call it 1.35 feet. So I went over to the box and measured its height as 1 foot 4.5 inches, or 1.375 feet.




In other words, an error of only about 2%. Not bad! I'll have to find some more fun ways to play with the little drone.

Winter Break

Finally back in Philadelphia after a three week break, which I spent almost entirely out of state.

In Minnesota

Spent lots of time with the family back in Minnesota. We got about a foot of snow while I was staying at my brother's place, so decided to get in some sledding. Also, tunneling through snowbanks.


My sister got me a copper mug for Christmas :D
Copper is my favorite metal and element. She also made me a copper-themed scarf last year (see photo below).

You're never too old for some fun flying toys. This crazy little mini-drone will actually come in handy for teaching GIS and Remote Sensing this semester (it's packed with some little sensors and a camera).

Meeting up with the crew at the Old Spaghetti Factory, then some ice skating at The Depot. Hard to tell, but I'm wearing a scarf with a series of color bands in it which represent the absorption spectrum of copper.

Munchkin: Adventure Time

Met up with my friend Zach at Shadow Falls in St. Paul to do some educational geologizing. We put together some video shots of us exploring the Falls and some of the local rock units. I'm excited to see the final product!

Spent a day or two in St. Paul. Met up with some old coworkers from the Health Department. Their Wheatstone Bridge is pretty great. 


In the Dominican Republic

For the last week of winter break I went to the Dominican Republic with my family. We stayed at a resort in Punta Cana. It was warm and sunny and generally quite tropical. 

Spotted a little island on the way to the Dominican. I wish I knew more about little tropical island geology...

The northern coast of the Dominican. A very long 5-hour flight, especially considering 4 of my infant nephews were onboard.
I spotted this scarp which seemed to extend across the entire country (sorry for poor quality). It must be 50-100 feet tall? I couldn't find any information on it, but it was curious.

Between the long break and the flight, I had plenty of time to finish a few books. Finally finished "The Voyage of the Beagle," which was quite good. I might have to do a review of this book later.
I absolutely loved this book. I'm a huge Discworld fan, and this was just great. Another book worthy of a science review.

One of my favorite parts of the trip was exploring some trails and beaches on some dirt buggies. It was very dusty, so good thing I brought my trusty bandana, which I got a few years ago while on a geology trip around the Big Bend area of Texas, which I wrote about slightly in this old post.

Stopped in a cave while exploring on dirt-buggies. Ah, the limestone!

Stopped at the beach!

Saturday, January 9, 2016

First Semester Recap: Geo-Cake!

To celebrate the end of my first semester back in the world of geo-learning, I (with the help of Emily, another of the grad students) made some geology-themed cakes for our labs. Delicious and educational!

Creating the layers. The one in the foreground is supposed to be a chocolate-chip conglomerate



Neither of us had done this before, but we figured we'd just make a few small layers individually, then weld them together with some fudge or frosting. It actually turned out not half-bad!

Nearly done! From top to bottom: rice crispy aquifer (both vadose and phreatic), conglomerate, basalt, and metamorphic basement rock.


Adding a little sugary geomorphology.

Excavation! A final chance to explain some layer-cake geology, and plenty of sugar for their minds to process it.

We ended up making two batches of cakes (since we had labs at different parts of the week) and had the system down pretty good by the end. Pretty much all of the cakes got eaten up between the labs, faculty, and other random students. A success! Would do again.