So I was surfing a bit the other day amongst some of the science/tech sites I read often, some of which inter-link with each other, minding my own business, and before I knew it I was reading a story on Live Science. (I have it linked in my blogroll, down there. Yeah, thataway, on the right, under "Science and technology," because it's, well, mostly about stuff like science. You know, and technology.)
Now, I don't expect most stories I read there to read like a real tech journal, because they're written for a broader, less-focused readership. But I do expect writers to at least get the technical stuff right, and get a little actual science in there now and again. Seems reasonable to me, seeing as they have "technology" right up there on the label, top center, just to the right of the word "science." (Alright, so I suppose I've made my point.)
I followed this particular link because the title intrigued me: "All Earth's Electricity Mustered to Destroy an Aluminum Can." You have to admit that the idea of all the earth's electricity being "mustered" to any particular place for any purpose at all, let alone the destruction of an aluminum can, warrants a little investigation. And, as it happens, I know a little bit about electricity. This would be a little like Eugene Volokh reading a story on "All Earth's Lawyers Mustered to Sue an Aluminum Company," or something like that. At least he would want to check it out. So I did.
First of all, the title has nothing to do with what happens in the story. Not a thing. It implies that all the electricity on earth was somehow gathered up and brought to bear on this little aluminum can in Nevada, which is not the case. Well, maybe the story will clear things up. First sentence:
At a government test site in Nevada last week, scientists generated a brief electrical pulse four times as powerful as all the electricity on Earth.
They didn't even get one sentence in before not only being ambiguous from a technical point of view, but being utterly illogical as well. Suppose I made this statement: "Last week I briefly had four times as many people in my kitchen as there were in my entire house."
How can there be more people in my kitchen than in my entire house? Similarly, how can any electrical pulse be "four times as powerful as all the electricity on Earth," unless said pulse were not on Earth at all? (I checked on eBay, and Nevada is still earthbound.) I can only venture a guess as to the writer's intention, which is that this pulse involved four times more electricity as is typically found on Earth at any one time.
But even making that assumption doesn't clear things up. The story states that this electrical pulse was "four times as powerful" as something else. In physics generally, and electricity specifically, "power" is a very particular quantity which is defined carefully. Generally speaking, power is the product of force and velocity, velocity also being the displacement due to that force over time. In electricity specifically, power is the product of electro-motive force (EMF) in volts, and rate of current flow in amperes, said current being the amount of displacement of electrical charges over time (coulombs per second). Both equations for force are similar, differing in the same ways that electrical current differs from throwing a rock. In any case, it is very specific, and does not represent the amount of electricity present any more than you can know the amount of power in a rock simply by knowing how much rock you have. Saying this electrical "pulse was four times as powerful as all the electricity on earth" means they know how much power that was, right? Inquiring minds want to know!
They don't say if they do know. Actually, they do tell the amount of electricity that discharges through the can, nearly 19 million amperes, but as we have seen, this hardly tells us the amount of power that was in that pulse. If the writer thinks he is answering the question of how powerful the pulse was, or if he thinks that 19 million amps is twice as powerful as 9.5 million amps, he is the wrong choice to write this story. We know the electrical discharge was immense, but we kinda wanted to know just how immense.
Ok. Next, they tell us that this electrical discharge caused the aluminum can-like structure to accelerate "in an instant" to 27,000 mph, roughly escape velocity, and that the pressure in the chamber where this took place was similar to that at the center of the earth, "where iron goes liquid."
Lots of problems here. Nothing accelerates in an instant. A finite time was involved which was hinted at in the second sentence: a few millionths of a second (microseconds, or µSec). Just how many we are left to guess. And the pressure? The story implies that the pressure is so great as to cause iron to go liquid. Folks, all other things being equal, pressure does not cause iron to go from solid to liquid. Pressure causes a gas to liquefy and a liquid to solidify, not the other way around.
So yes, there is some liquid iron near the center of the earth's core, and there is tremendous pressure there, but the temperature is what liquifies the iron. (It begins to turn solid at the very center as pressure overcomes the effects of temperature.) Again--wrong guy for the job.
My curiosity was piqued, though, as I realized that the aluminum can began to move at a high rate of speed, and I began wondering just how far it might have moved. Since the writer never tells us, we are left to guess for ourselves.
27,000 mph is in fact slightly higher than escape velocity from the earth's surface, but we'll use their figure anyway. That translates to...hmmm...5280 feet...divide by 3600...(should I convert to metric?)...that comes to 39,600 feet per second. Now, how long is it traveling at this speed? We only know that it manages to get there, and the whole process takes "a few" µSec. So, ignoring problems of acceleration and deceleration, etc., for a simple point of reference, how far would this object travel if it were moving at a constant velocity of 27K mph for only one µSec? Turns out that comes to 0.4752, or nearly one-half, inch. Not very far, but we don't know how far the object is actually allowed to move during the whole procedure. It could be several times this distance depending on factors we don't know--because the writer never tells us.
And judging from what he does write, he likely never guessed he was leaving so much out.