The Very Spring and Root

An engineer's adventures in education (and other musings).

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BTR Selection Day Debrief

So, BTR Selection Day was amazing. Took a bus into Dorchester, a very working class neighborhood in south Boston. Here I am obviously lost and wearing a suit. People were very friendly though, struck up some great conversations.

Checked in at the Burke High School, during a normal school day so wading through a sea of students, and found my pod… Pod 6, HS Science candidates. I was very impressed by the caliber of my podmates… a computer scientist with a minor in math from Harvard… a U Michigan neurobiology major… a rising biomedical researcher… you get the idea. A very humbling meet-and-greet.

The founder/director of BTR greets us, a former math teacher in BPS himself. A bit rambling, but very motivational speech.

Group activities are up first, where we are given a sets of incomplete personal and academic information on a student case study… as a team of teachers it is our job to debate and conclude on what is going on and what our pathway forward should be. All the while the observers are hovering and scribbling notes… no pressure.

Then sample lessons. Pod 6 is invited into the classroom, 11th grade chemistry, urban public high school….  The lessons go well though, and I think mine did very well. I had restructured my Kepler lesson to be more student-inquiry-based and participatory, drawing multiple analogies to similar systems, and designed to guide the students to forming their own conclusions. They got it. And more, they seemed really hooked by the end. It felt so good.

20 minutes for lunch. Brief socializing with potential future colleagues while wolfing down sandwiches.

Two separate interviews, one focused on on personal qualifications related to the application/resume, and the second apparently on philosophy of education and awareness of contemporary issues in American public education.

A content assessment, testing basic knowledge of the subject and a 30-min free response: “Design an experiment to teach the principle of conservation of linear momentum. Identify the equipment, process, data to be collected, analysis procedure, and learning outcomes.”

Finally, a writing assessment, asking us to use information from the pre-reading to write a persuasive essay defending one of several approaches to teaching science. Essays will be evaluated on structure, logic, use of data available, and indicators of strong integrated thinking and leadership potential.

So, a very exhausting but exciting day… overall impression was that it went very well for me, but we’ll see… I’ll hear back in a week, January 20th.

Made sure to sample the local cuisine, particularly what the natives call “cuppachawdah widda beah”. Delicious of course.

Icing on the whole trip: the following day I didn’t have to get to the airport until early evening. I made it to the JFK presidential library and museum… among other inspirational points, the multiple exhortations to service of an ideal, a social good, a higher calling… definitely put a cap on it. Bought three books, and flew home.

On the Verge of Something Great

I’m feeling nervous and excited for my final BTR interview. I’ve done the pre-reading, watched the video we were supposed to watch, prepared my lesson, printed my handouts, analyzed the organization’s content, press, and evaluations, and of course done a whole hell of a lot more thinking. Now I’m all packed and ready to leave tomorrow morning on a flight bound for Beantown.

I’ve updated my five-minute TFA lesson to fit BTR’s seven-minute format and explicit emphasis on student-driven learning. I removed a lot of the background and “telling” and instead have a series of questions prepared to guide students themselves through the logic train. I have about a three minute reserve to allow for questions and thinking/debating time. If they go through it quickly and time permits, I plan to lead them to draw parallels between the potential/kinetic energy tradeoff of the planetary system with more simple examples, like pendulums or springs.

NASA card prepared… How do we know where the planets will be at a specific time? It will take the Curiosity / Mars Science Laboratory mission 8 months from launch to landing to reach Mars… The Red Planet isn’t staying still in the meanwhile How do we know where it will be? And it just so happens that January 11, the date of the sample lesson, is when Curiosity will be pulling a major maneuver, so it’s timely and appropriate as well.

Do I got this? I got this. I’m still nervous and double/triple checking everything though. I guess that’s a good thing. I learned from theatre that any actor who tells you that they don’t have stage fright is either full of shit or not taking it seriously enough. Signs I want this.

5 Minute Lesson: Kepler’s 2nd Law

Instructor: Mr. Nalin Ratnayake
Subject: Physics (algebra-based)
Target Grade Level: 11/12
Lesson Objective: Understand the major implication of Kepler’s 2nd Law.

Good morning class. Have you ever wondered about the motion of the planets? My name is Mr. Ratnayake (Mr. Rat will do). Today we will discuss Kepler’s 2nd Law of Planetary Motion, building on your previous knowledge of basic mechanics, algebra, and geometry.

In the early 1600’s, most astronomers believed that if the planets orbited around the sun, they must do so in circles. However, astronomical observations did not agree; planets seemed to move randomly in the sky. It was a mystery. A German mathematician named Johannes Kepler forever changed astronomy by demonstrating in his *first* law of planetary motion that by simply treating an orbit as an ellipse, instead of the previously-assumed circular shape, the simplicity and harmony of planetary motion became clear. He then went on to explain the consequences of elliptical motion in his *second* law, which states: A line connecting a planet to the sun sweeps out equal areas in equal times.

Refer to the diagram on your handout, or follow me on the board. Suppose I have here my orbital ellipse, and I consider the area swept out by the radius r in some interval of time. The planet has moved on an arc, by an angle θ as measured from the sun. Now we have set up our problem and will commence, like good scientists, to ask questions.

What basic geometric shape does this look like? (Triangle). Let me draw this triangle. Who knows how to find the area of a triangle? (one-half the base times the height). Ok. Do we have a variable on our diagram that looks like it would be the height of the triangle?  (the radius r).  And this arc forms the base. What is the length of an arc (You remember from geometry of course, it is the radius of the arc times the subtended angle.)  So the area (A) of this pie wedge is…. ½ (r θ) r , or ½ r2θ.

Let’s assume, as Kepler did, that this area must remain constant for the same time interval in an orbit. Consider our diagram. If our planet moved closer to the sun, say here, then the radius, our distance to the sun, is much smaller. To maintain the same area of triangle, what must happen to its base? (must get larger). Remember, this is the arc length we traveled in our orbit for a set time interval. We traveled farther in the same amount of time than we did out here! What can we deduce about our speed? (we went faster!). We move faster when we are near the sun on our orbit and slower when we are far from the sun on our orbit.

Was Kepler right? It turns out that his theory exactly matched observational data from astronomer Tycho Brahe; this explained previously erratic motions of the heavenly bodies with a simple concept. Today, Kepler’s Laws enable us to predict the motion of the planets, asteroids, comets, and satellites in space. NASA’s Mars Curiosity probe just launched this week. It will take 8 months to reach Mars. Thanks to Kepler’s Laws we know exactly where Mars will be and how fast it will be going in 8 months; and Curiosity will be in the right place at the right time.

Check for understanding, all together now, and I’m looking for every one of you to answer. As a planet gets closer to the sun, does it speed up or slow down? (Speeds up!) As a planet gets further away on its orbit, does it speed up or slow down? (Slows down!) Good. Any questions?