This continues the saga of things I learned while developing the interactive Khan Academy exercise Visualizing Derivatives.

As described in the previous post, I seemed to get a few things right from the start. But perhaps more interestingly (and certainly more memorably), I learned some hard and important lessons along the way. Namely, a little planning with some humble tools can go a long way.

I recently shipped a new exercise on Khan Academy called Visualizing Derivatives. The exercise seeks to test students’ ability to intuit and visualize how a derivative relates to a function.

To users, the exercise appears fairly straightforward, but I found it to be an interesting and nicely-scoped engineering challenge. I was fortunate enough to get some things at least somewhat right from the beginning, which I’ll share here. Plenty of things didn’t go so nicely. I write about one big lesson I learned in the next post.

Disclaimer: This is intended mainly for beginners to web development. Also, these tips assume you’ve already read through the Getting Involved page and gotten set up with the basics of git, etc.

Several months ago, I learned about the Khan Academy’s open source Exercises framework. I had never before contributed to an open source project and was pretty new to web development. KA’s Getting Involved section was packed with helpful starting points. It seemed like a great opportunity to learn while helping real users in a very tangible way. So, without further ado, I dove in.

Lately, we’ve had a major ant infestation in our main bathroom. There are some sizeable cracks in the wall near the bathtub, and the ants have transformed our humble bathroom into a veritable ant city. They bump heads in a little ant-street formed at the base of the bathtub, and have made inroads around the sink basin and inside the bathtub. Each day, a few adventurous souls make it to the toilet and take to scaling the walls.

My housemates got ant baits that don’t seem to be working terribly well, and I haven’t really done much besides wash out the ants from the tub before I shower. I fill up a large plastic bowl with water from the sink and swoosh the ants down the drain.

Maybe I should be more proactive about “taking care” of the ant problem, but I have found the ants’ presence to be surprisingly grounding and a useful reminder to be mindful. How?

When we talk about achieving a personal goal, such as losing weight or getting a job, we tend to focus on the mechanics of the process: how often to exercise and what to eat, which companies to apply to and when, etc.

But so often, we end up falling behind, getting discouraged, and ultimately not meeting our goals. In these cases, it’s not enough to just talk mechanics. Something more fundamental is needed, something to keep us moving forward even when we are painfully aware we’re off-track.

That something is a story.

Note: As the 2011 senior class president of the Duke Engineering Student Government, I had the distinct honor of delivering the Pratt School of Engineering student graduation speech. It sounds kind of awkward when read, because it was written to be spoken. =/

Dear Pratt Class of 2011, we’ve made it. After four years of hazing by Epsilon Gamma Rho, taming the beast that is MATLAB, and eventually succumbing to senioritis, we are here. To family and friends attending today, thank you for your support. We couldn’t have done it without you or your money. Just kidding; checking to see that you’re awake!

I figured a lot of exclusive awards are going to be handed out today, so I’d like to share a personal story that reminded me of a substantial achievement that every one of us can claim as our own.

Note: This post, which I wrote the summer after my freshman year at Duke, was originally published on the Howard Hughes Research Fellows Program blog. I ported it over here as an homage to my past life in biology research. Also, from a conceptual standpoint molecular cloning remains pretty interesting.

My goal this summer has been to generate an animal cell line that can give off a measurable signal when a certain cancer-related gene is expressed, or made into protein. Specifically, I am trying to place the regulatory sequence, or “promoter”, of the ARF gene before the DNA sequence which codes for the fluorescent protein mCherry. When a certain wavelength of light is shined on cells expressing mCherry, the protein emits another wavelength of light which appears red in the visible spectrum. Cells which contain this new DNA and have ARF activated will respond to excitatory radiation by shining red. Those without ARF will return a weak signal or no color at all.