Weekend Diversion: Why is Oil in the oceans so frightening?
Category: Environment • Physics
Posted on: May 2, 2010 1:41 PM, by Ethan Siegel
http://scienceblogs.com/seed-img/bg_blockquote.gif); background-repeat: repeat-y; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; quotes: none; background-position: 0px 0px; ">Either write something worth reading or do something worth writing. -Benjamin FranklinEvery weekend, I try to bring something light to you, but there's a lot of heavy stuff going on in the world right now. So instead of the usual, I'd like to tell you just a little bit about why putting even a little bit of oil in the oceans can be so disastrous.
And I can't think of a better modern voice to take us through that than Regina Spektor, whose voice reminds me of greats such as Nina Simone and Ella Fitzgerald. Take a listen to her song Apres Moi.
Most of you know that if you take pretty much any type of oil, it will float on top of water.
But what if the amount of water you have is much, much larger than the amount of oil that you have? It turns out that the oil will spread out over the surface as much as possible.
How much is as much as possible? Until the oil on the surface of the water is just one molecule thick. So, how thick is one molecule of oil? Believe it or not, Ben Franklin was the first person to measure it, and you can measure it, too! All you need is some oil, an eyedropper, and a flat, clean body of water.
The eyedropper is great, because a single drop of anything that comes out of an eyedropper is going to be almost exactly one milliliter of volume, or one cubic millimeter. That's tiny, isn't it? You'd have to line up one thousand drops in a line to get something one meter (a little over three feet) long. But when you drop just a single drop into a flat pool of water, it spreads out to make a circle that's huge!
This single drop, which was just a millimeter in size (about 1/25th of an inch), now spreads out to a diameter of 24 feet, or over seven meters!
If I work out my math, that means a single molecule of oil is only about 2 nanometers (or 20 Angstroms) thick!
(Beware of the number one hit on google, which unwittingly uses far less than a milliliter of water in their experiment, and gets an answer that's almost 50 times too large!)
Well, what does that mean if -- instead of a drop of oil -- I dump an entire gallon of oil into a large body of water?
It would spread out to make a circle that was 450 meters in diameter. That's over a quarter of a mile. From just one gallon (about 3.8 liters).
And what about the Oil Leak which is spilling oil into the gulf of Mexico right now?
It's currently spilling an estimated 200,000 gallons of oil into the gulf of Mexico every day.
In other words, every day, a new 125,000 square kilometers (or 50,000 square miles) of ocean will eventually get coated in oil when it finishes spreading out. That's almost as big asNew York State.
Practically, of course, this much oil won't spread out to be one molecule thick; more like 100 molecules thick in most places, but that's still a huge disaster! Many of you will remember the Exxon Valdez spill and the consequences this caused:
Well, the one in the Gulf of Mexico, as I write this, is only seventeen miles away from the Mississippi Delta. It's one thing to look at pictures of animals killed from an oil spill.
This isn't only about animals this time. This isn't happening in a corner of the world where very few people live. This is happening in a place that will affect millions of people. And by time this leak is fixed, we may well exceed the total volume dumped by the 1989 spill. This is about your world, your oceans, your environment and for many of you, your own health.
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