I didn’t know that liquid oxygen is blue until last Friday, when my physics professor brought it to class and let us play with the three-hundred-Celsius-below-zero substance.
A bar magnet (ferromagnetic), liquid oxygen (paramagnetic), andliquid nitrogen (diamagnetic)
I did have a vague recollection of being told before that liquid oxygen is magnetic, but in class, we briefly learned why. Although liquid oxygen has an even number of electrons, molecular orbital theory decrees that two of these electrons abstain from pairing up and canceling out each other’s spins. In other words, liquid oxygen is paramagnetic. Each “spinning” charge looks like a loop of electrical current and produces a magnetic field. In the presence of another magnet, the electrons turn so that their magnetic fields align with the external field.
In a magnetic field, such as that from a bar magnet, the tiny magnets of liquid oxygen’s unpaired electrons align (left). Normally, they point in random directions (right). (Image fromWikimedia)
Now, under the influence of an external magnet, the paramagnetic material has itself a net magnetic field. Further, its North and South poles are aligned with those of the external magnet. Voila, we have magnetic attraction.
The liquid oxygen in the beaker behaves like another bar magnet pointing in the same direction as the real one, and is thus attracted to it.
One thing I really like about my physics professor is that every time he performs demos, he invites everyone to come play with the equipment after class. When we do, it’s practically unsupervised—except for maybe an offhand warning to wear gloves when handling the freezing substances. It makes me feel like an adult and exemplifies either his personal trust for students or trust deriving from Caltech’s Honor Code—or maybe both.
At Caltech it is a graduation requirement to take a “menu” class, courses which introduce you to areas of study outside of your major. This year, there were three courses offered in the third term: ESE 1, Ay 1, and Ge 1. I took Ge 1: Earth and Environment for two reasons. First, ever since the first term I have been interested in the idea of minoring in geology (I might major in it instead!) and the class piqued my interest. Second, the class has an awesome multi-day field trip. While I’m not usually a fan of the outdoors, preferring to stay inside and read books or watch anime, this trip was the highlight of my term. As we went up the 395 along the Eastern Sierra’s, the geological makeup of California was revealed before my eyes. So come on a journey across California with me through my Ge 1 field trip photo gallery.
I’m starting a new miniseries on the blog – Film Club! Each episode, I’ll share a short clip from a popular piece of media, and then completely dissect and overanalyze it, because let’s face it, I’m doing it in my head already anyway. You say “buzzkill.” I say “science.” We’ll kick things off with a clip from Gravity Falls I discussed a bit in my previous post: Season 2 Episode 12, A Tale of Two Stans. If somehow you haven’t watched this show yet (?!)… spoilers incoming!
It’s crazy to think that I began applying to college almost three years ago. I still remember spending hours looking at college websites, admissions blogs and reddit pages to try to get a sense of what college is ACTUALLY like. To help you get through these stressful times, here are a few tips that I wish I had listened to. Hopefully, these will ease your worries and maybe even make the process more enjoyable!?