17th birthday

Today's my 17^th birthday. It happens to be on the same day as a chemistry exam. Ah well.

The post isn't about how I am celebrating it; rather, it's just another digression on things I'm interested in.

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Firstly, I would like to reiterate that an examination should be a way of testing if the students understand and can apply the subject. It is not meant to be a device to trick students into all sorts of pitfalls. This is what gives exams a bad name: why should exams be a place where you force people to get it wrong?

The most devious tricks I can recall right now are:

• Deliberately putting an answer for a person who forgot to convert units.
• Use ambiguous words/ask ambiguous questions.
• Make statements that have exceptions (no matter how minor) to them.
  

The one I want to highlight is the second one: use of ambiguous words. When a person says something, the meaning must be absolutely clear for someone who is acquainted with the subject. If I say, "what is the f of a camera?" I am causing a confusion for the student. The student can wonder if I am referring to the "focal length" or the "f-number", which are quite different. In multiple-choice questions, ambiguity is especially harmful, because one mistake and you get no credit at all for the question. Specifically, I am insinuating that the poor usage of the phrase "valence shell electron pair" makes it ambiguous as to whether double-bonds count as one so-called "pair" or two pairs. That is why I did not like the first question of the chemistry exam.

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Recently, I have been working on computer simulations of differential equations, but I haven't been too successful so far. I managed to successfully simulate the differential equation of a rigid pendulum of any angle using numerical approximations. However, when I attempted to simulate 2D wave equations, things not only got messy (numerically approximating a Laplacian is difficult), but the waveform became "polarized" (the wave crests and troughs gets sharper and sharper) as time goes on, implying that my simulation was rather unstable. I was also a bit ambitious and wanted to simulate the 2D Poisson's equation for gravity or electromagnetism, but became confused about how the equation works. It sounded like I have to find the "inverse" of the Laplacian on the density function, but I have no idea how that could be done, or if it's even possible. I did all the simulations with Python and pygame.

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Enough about simulations. I'm back in my "story mode" again: on my daily walks I tend to fantasize about all sorts of crazy tales of characters - it really reminds me of how I used to play with "anthropomorphic items" (at least I felt they were; imagine a talking hair-clip... weird) and give each of them a character to role-play. It's sorta like a role-playing game, but where I'm the director and I just tell them to make a movie. Nowadays, since I don't have them accessible, nor do I have the time to play with "dolls", I began a new way of expressing creativity: telling stories within my mind. It's a way of passing time, because walking 30+mins a day gets routine over time.

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Now Thanksgiving is pretty close, I might as well spend some extra time revising for finals and complete some incomplete tasks on my task list. Anyway, Happy Thanksgiving!