Saturday, February 27, 2010

Integration by weight

Some randomly firing neurons just gave me a flashback to a very unorthodox means of doing calculus: Integration by weight.

Here is what happened: Some years ago I was taking a class in thermodynamics. As part of this class, there was a lab (I don't specifically remember what it was about, but there may have been a Stirling engine involved); and in the course of this lab, a contraption produced a two plots of some quantities relevant to the physics involved on a large sheet of paper.

For whatever reason, it was necessary of us students to integrate this printed plot (effectively to find it's area). So, we spent some time rubbing our heads as to how to do this. We discussed several options, like dividing it into triangles and doing some sort of approximate estimate that way. But all of these methods seemed very time-consuming and tedious. So it dawned upon us: We could weigh it. Said and done, we cut the blob outlined by the plot out of the paper, as well as some reference samples to get an average weight of the paper.

Worked like a charm. Granted, we had access to an analytical balance with pretty high-precision, but still, there is something very appealing about the fact that this works.

Friday, February 5, 2010

Useful URL tips for google and youtube

A short list of simple but useful tips for youtube and google URLs.

Link to a specific time in a youtube video

Attach #t=AmB where A is minutes and B is seconds to a youtube URL, to link to that specific time in the video.

Example: http://www.youtube.com/watch?v=wRnSnfiUI54#t=0m16
links to the specific moment where Kirk shouts KHAAAAAANNN!

Google in English

Occasionally, google gets it in it's mind that you want the interface translated to some language other than English, because you are in a country that speaks that language, or because of (broken?) geo-profiling. To clear this, visit

http://www.google.com/ncr

Google query on the fly

If you need to do a quick google query, and want to limit the bandwidth used by only loading the results, or the pages loaded because you're in an awkward text-based browser, learn this URL scheme:

http://www.google.com/search?q=a+google+query, where a+google+query can be replaced with whatever you're searching for.

That is all.

Thursday, February 4, 2010

I digress: The elusive experience of being lost in a familiar place

Deviating a bit from the set topic of this blog, I thought I'd share a quest of mine in life: Loosing myself in familiar places.

When I was very young, probably around 8-10 years of age, I had a most peculiar experience as I woke up one morning. I was convinced I was lying in one direction in bed (not that I remember specifically which orientation, but for the sake of the story, let's say I imagined myself facing the wall next to my bed), only to open my eyes and find out I was facing away from the wall. For the briefest of moments, I experienced a peculiar but pleasant feeling of confusion.

It is hard to put this experience in words, but if you have ever had a false awakening (that is, dreaming you woke up and started doing your morning routine, only to wake up for real moments later and finding you're still in bed), the experience is somewhat similar.

Ever since this morning in my childhood, on some level, I have been chasing this experience. It is quite elusive, as it is very hard to make yourself forget how you got somewhere, since trying typically has you paying more attention to where you are. I have indeed experienced it more times, usually while lost in deep thought about some matter, only to realized I've been wandering around randomly.

These events are rare, probably occurring order of magnitude once a year. But today, was one of those days. While pondering a problem from a textbook on plasma physics I was reading, I went to the lavatory, only to realize I had no idea which floor I was on.

They seem like such tiny and insignificant events, but given their rare and transient nature, I feel it's necessary to cherish and take the opportunity to explore them.