Model depicting where the oil has and will travel (courtesy NOAA)

A few weeks ago, the Bay was inundated with 58,000 gallons of bunker oil. Most Bay Area beaches have been declared safe and that the threat is behind us….Thus far, they have recovered 20,000 gallons…so what happened to rest of that oil?

According to the EPA, oil undergoes 5 natural processes once spilled.

1. Weathering - chemical & physical actions that make the oil heavier than water so it sinks(generally from wave action)
2. Evaporation - lighter ingredients in the oil evaporate leaving behind heavier tar-like substances that can sink
3. Oxidation - when oxygen combines with the oil hydrocarbons to produce water soluble compounds. This typically happens around the edge of the oil slick
4. Biodegradation - when bacteria feed on the oil to break it down. Typically, this only happens in warmer water than the Bay.
5. Emulsification - Wave action forms emulsion of water and oil, just like mixing a salad dressing. The result can look like a tar ball.

What was spilled was #6 bunker oil, which is an extremely heavy oil. Only 5-10% was expected to evaporate over the first day. In addition, the specific gravity, the relative density compared to water, is about 0.95 to 1.05. That means a fair amount will sink to the bottom of bay.

So when only half of the oil gets recovered, we can safely assume a fair amount has sunk to the bottom of the bay, a fair amount just diffuses along the surface, and finally a fair amount is stuck to shore.

Takeaway:
Clean is a relative term. That oil will be around the bay for YEARS…..just lying below the surface.

More Info:
Cosco Busan Cleanup Site
EPA Oil Spill Education Center

Since our topic this week will be related to the use of Magnetic Resonance Imaging, or MRI, I thought I would write up a few words about how an MRI works. However, as I was googling around the internet, I came upon a pretty good write up on just that. I’ll give you the link further down the page since I don’t want to reinvent the wheel, but I just wanted to discuss one thing first. While reading some of these MRI articles, I realized that for most of them a knowledge of the physics of angular momentum was assumed. Angular momentum is an interesting phenomenon, it is one that keeps the earth spinning so we have day and night, keeps us stable on a bicycle, and is a key component of how an MRI works. So lets talk a bit about angular momentum.

Have you ever played with a top — you know the toy you spin that balances itself until it slows down too much? Or maybe, you’ve gone to the science museum and picked up a high tech top, a.k.a. a gyroscope.

There are two main concepts we talk about when describing the motion of a top, there is the spin, that is, motion around itself; and the precession, that is, the motion about an imaginary vertical line drawn from our table toward the ceiling. (If you think about the Earth, the axis of rotation is more or less a line drawn from the North Pole to the South Pole.) If you spin a top perfectly on a perfectly flat table it will just spin happily with no visible wobble (i.e. no precession) — in this case the axis of the spinning is exactly vertical and thus aligned with the axis of the precession. If we mounted a laser inside the the center of the top so that it is aligned with the spin axis and shoots a beam up towards our ceiling, then as the top spins steady on the table the laser with point at one spot on our ceiling and not move. In fact, if you ever-so-slightly incline the table, the top would move down the table and the laser would move along our ceiling in a straight line following the motion of the top across the table.

But if you lightly tap your top without disturbing its spinning, then its motion takes on another dimension — the spin axis will start to precess around that imaginary vertical line (or what is usually called the axis of precession). That is, it’s spin axis will rotate around the axis of the precession so that our laser would continually trace a large circle on the ceiling.

As an aside, have you ever played with a gyroscope? A good toy top will spin for a few seconds or maybe up to a minute, but even a cheap five-dollar gyroscope from your local science museum can spin and maintain it’s balance for long periods of time. The reason for this is due to their shape. The shape of a gyroscope is designed to max out the amount of angular momentum that it can store. As you have probably noticed already, I am a fan of Wikipedia, but the article for angular momentum goes a bit further than I want to discuss now. If you are interested check it out.

Ok, so what does all this have to do with an MRI? Well, I just wanted to get your mind thinking a bit about angular momentum because the MRI uses this concept, not with tops or gyroscopes or the Earth, but with individual atoms. The MRI manipulates the precession of the atoms in our body in a specific manner such that it can detect changes in the atom’s angular momentum! So without further ado, check out this article. The article is rather thorough, so if you are just interested getting down to the brass tacks, Section 7 How it works: Atoms and Section 8 MRI Machine provide all the essentials.

The DtaS Science in Action event - the Stanford Linear Accelerator was an amazing event. 20 people were able to get a 1st hand look at the one of the premier particle acclerators in the world.

We all gathered for a half hour explanation of particle physics…that quickly turned into an hour with all the fascinating questions (leave to science cafers to come up with good questions). We then spent another hour looking at the accelerator itself, along with more fascinating discussion on the research conducted there. Rather than my take, here’s a recap from David Ferris, an attendee from the tour.

Adam gave this analogy to explain atoms. Let’s say you puffed up an apple so big its diameter extended from the Earth to the sun (take that, New York!). If an apple were that huge, how big would one of its atoms be?

Answer: the size of a football field.

OK so far. Pretty small. But does that mean that this magnificent apple is made up of football-field-sized chunks? No. All that means is that the components of an atom – its nucleus and electrons – exist in that football-field sized space.

So how big are the nucleus and electrons? The nucleus, Adam continued, is the size of an apple seed in the middle of that football field. And the electrons are far smaller than that. They are, in Adam’s words, “the size of a small virus,” which is to say, so small they’re hard to measure. In fact, Adam concluded, electrons don’t have any mass at all, as we humans understand it. Oh, and they don’t really exist anyplace, either. There’s just a probability they exist.

This means that all matter – your hands, your mouse, the coffee cup, the screen upon which you read this – are made up of infinitesimally teeny bits of almost-nothing. How can something that appears so substantial in fact be the exact opposite? Mind blown. Game over.

More Info:
Ferris’ entire post

KQED QUEST never lets me down, here’s a good story on neuropyschology-research at Stanford using MRIs…the same technique used by our upcoming speaker, Dr. Phillipe Goldin. In this story, they are studying how children with various levels of reading skills have different neural patterns.

With the fMRI, the subject has to stay still for upwards of 45 minutes in the machine. The fMRI does only measure blood flow rates, which by all accounts is only one useful measure of brain activity. Nonetheless, this is a fascinating methodology with great potential for our understanding of basic neural processes.

On Tuesday, the California water wars (the fight between water rich NoCal and people/silicone rich SoCal) made national headlines by getting press on the Jim Lehrer News Hour. Here is the 10 minute video:

Takeaway:
Water is the new oil. This is probably the biggest issue facing California over the next 10 years. The biggest issue at hand is population growth, we just don’t have the water to keep up with growth and maintain the huge agricultural industry. By most accounts, conservation won’t make a big enough dent and no one is willing to say stay out to new Californians. Bet on this: there will be a bond measure re: California Water system in the fall of next year. My prediction: water rates will go up, the environment will suffer, and voluntary conservation calls will continue (I expect a mandatory conservation to happen next year).