Skip to comments.Massive electric current tested in US
Posted on 07/29/2005 2:28:26 PM PDT by Grendel9
Thursday 28 July 2005, 12:01 Makka Time, 9:01 GMT
The test was part of an operation to test US nuclear capability
Scientists at the Nevada Test Site have said they generated a current equal to roughly four times all the electrical power on Earth.
The current, which created pressures in materials millions of times greater than normal, was part of an experiment to better understand nuclear weapons.
The experiment was conducted on Wednesday at the test site's Atlas Pulsed Power Facility by scientists from Los Alamos National Laboratory in New Mexico, along with staff from the test site and contractor Bechtel Nevada.
19 million amps
During the few millionths of a second that it operated, the 650-ton Atlas pulsed-power generator discharged nearly 19 million amps of current through an aluminum cylindrical shell about the size of a tuna can, the National Nuclear Security Administration said.
Atlas, which works as a giant power multiplier, was designed as part of an Energy Department programme to determine the readiness of the nation's nuclear stockpile without underground testing.
It was built at Los Alamos and recently moved to the Nevada Test Site, a proving ground just north of Las Vegas
Quibble: escape speed is 25 000 mi/h near the earth's surface.
This is an excellent post. It shows knowledge of physics and explains things clearly and concisely. You have brought the discussion of a technical subject to the right level of detail without being pedantic.
Most people have no understanding of physics and everyday conversation doesn't have the same precise definitions for ideas like power and energy and motion. For example try to tell someone that the brake pedal in their car is an accelerator. In physics it is an accelerator as is the steering wheel when going around a corner, but neither of these devices will ever be an accelerator in common conversation.
In the imagination of popular culture, a 100 Watt bulb will always be more powerful than a 60 Watt one. This is often a source of confusion when moving to scientific subjects.
I remember seeing an Air Force magazine back in the early 90's of a B-52 (BUFF) on a big wooden platform. The Sandia guys used the wooden platform to zap planes and other systems with big EMP jolts to see how well they'd survive and what could be done to shield them.
Like this one?
Thanks, stripes. Power and energy are confusing topics for most folks. Of course, since journalists know nothing about it but pretend they do, they are of no help. They pretend everyone else understands it, too. It would be nice if they would give a little sidebar whenever they talk about this stuff. If you want to read it, fine. If not, fine. But they should at least give it a shot rather than bluffing. And it is obvious they rarely run the stories past anyone who understands the topics, either.
wholey cow! :D
This is shocking news...
What a demure Pulsa !
Los Alamos? That means that China knows about it already.
Yes, but most people are not scientists nor have they as laymen spent much time, if any, studying science.
Of course, since journalists know nothing about it but pretend they do, they are of no help.
That is true of most subjects that journalists write about whether it is politics, culture, or science. It seems that their thinking goes like this: since we write about it we are right.
It would be nice if they would give a little sidebar whenever they talk about this stuff. If you want to read it, fine. If not, fine.
That would be ideal, but it will never happen. However the value of a place like FreeRepublic is that now there are public forums where the journalists can be the subject of criticism. Journalists have never had their stories questioned before in a widely accessible publication like a website.
Exactly; that is my point that the media was confusing demand and energy. I've noticed over the years that whenever I know something about a story being reported in the media, the reporting usually has errors in it (which doesn't lead to much confidence on my part in the media in general). The best reporting I've found is in the IEEE Spectrum (I'm talking about non-engineering articles...they had better be correct in engineering specific articles).
Sound cool! What type of experiments did you work on?
And here's another:
"On Tuesday, customers across the state used 32,075 megawatts _ enough to power 32 million homes _ between from 4 to 5 p.m."
You can't use megawatts. You can used energy (joules) at the rate of so many megawatts.
But I guess we could keep this thread going just like this until it gets cool. Speaking of cool, the hottest day this month where I am (Cleveland) has been 95, second was 93. Last month we had a 94. Sounds pretty cool compared to what some folks have been getting.
C'mon give 'em a break. It's not like they did something REALLY BAD, like spell "Havana" with two "n"s.
"mw/hr" should be "mw".
I agree with most of what you say and I previously mentioned those very things in my posts 41 and 43 and a few others. I just realize there might have been some confusion when I wrote, "You can't use megawatts. You can used energy (joules) at the rate of so many megawatts."
What I mean by that is not that you can't use the TERM 'megawatts' but that you can't use (in the sense of 'consume' or convert in some way) megawatts themselves. Energy is something you can use. Power is NOT something you can use since it is not a commodity but the RATE of using the commodity. You do not buy power (watts). You buy energy (watts times time). Therefore, what I was trying to say was that you CAN use (consume, convert) energy but you CAN'T use power.
You mention that they could have used the term 'watt hours'. I doubt if there are many reporters who know the difference between 'watts' and 'watt hours', assuming 'they' was a reporter.
You said, "Power plants are often described by the power they can generate..." 'Power' plants don't generate power! The generate (or convert) energy. Power is only an indication of how much energy they generate per second or some time interval.
I go back to my analogy that speed is to distance as power is to energy. Speed and power are time rates. The thing you want to get (distance or energy) is the product of that rate times some time. When you ride a plane, they don't generally charge you for speed, they charge for distance. The electric company doesn't charge you for power, they charge for energy.
The 'power' meter on my house spins faster when I use more energy per second. The speed of its rotation corresponds to my 'rate of energy use' (power), but I am using energy, not power. If I told the electric company I wanted to buy 1000 watts (with no length of time specified), they should tell me it is not possible. If I told them I wanted to buy 1000 watt hours, they should be able to do that. I am being picky on the terms but I want to make sure they are used correctly.
Go back to school if you ever were, and then get back to me.
"Thunder Clouds in China -Storm is Brewing"
I majored in physics, and have taught Honors Physics for 30 years and Advanced Placement (college credit) Physics for 15 years, as well. A lot of my students score 5 (highest) on the mechanics and E&M tests each year. They get the energy and power questions right.
I have to spend some time showing kids the correct meanings of energy and power since they have heard so many people using them incorrectly all their lives. I have read literature from electric companies that uses the terms incorrectly, too.
I would suggest you go to any college and ask any college physics professor and you will see I am right.
I said agreed with most (but not all) of what you said, so I am a bit confused about where your complaint is. Is it my statement that electric companies don't sell power? Or that you can't buy power? Do you have any complaints about my post 74? At least 'stripes1776' knows I am right. See post 53.
Interesting interpretation. I've found it simpler to think in terms of using power, but energy being a relative metric. A conductor might be energized to a particular energy level, but completely useless unless a circuit is completed to a different energy level, thereby allowing power to be produced. The energy is neither consumed nor created, but merely converted from Chemical to Mechanical to to Electrical in a typical petroleum fired electrical generator.
With respect to simple algebraic equations, I've found it more productive to intuitively grasp the metrics of Maxwell's Eqns in differential format used simultaneously with some insight of 2nd rank tensors to better understand what is implied or generates one term from the other.
So do you believe it would be more impressive to generate 4 times the total current or a current density four times greater than a previous record?
If you haven't already found it, I think you'd enjoy this site: Science Myths. It has an extensive section on electricity. I think that electromagnetic theory is the least understood area of physics. Feynman even gives the (incorrect) "rolling wave" interpretation of Maxwell's Equations in his physics books, eg. a change in B causes a change in E a "short distance away". Ummm, that would be action-at-a-distance.
When you say "interesting interpretation", which of the numerous things I mention are you talking about?
When I mentioned energy, I was talking about energy delivered to the customers. 'Consumed' in the layman's terms but converted, as I mentioned, in more scientific terms.
You used the term 'power to be produced'. That terminology is where I have the problem. I would say energy is produced (converted) at a certain rate. You can think of 'using' power, but the only way you can purchase it is by measuring how long you use it. That is why the electric bill mentions the number of kWh you use. They could send you a graph of the instantaneous power versus time and show you the area under the curve, along with you peak power, but they can't charge you for power alone. Instantaneous power is interesting since we can 'see' what is going on and it does measure the stress on the delivery infrastructure, but energy delivered, (the area under the curve) is what we buy.
As far as being more impressed by current or current density, since current density is current divided by area, there are several ways to increase it. If we are looking at the main transmission line alone, the area of it will remain roughly constant, so quadrupling the current will quadruple the current density. I am equally impressed.
When someone proclaims a new power record, the public does not realize what it means. They don't realize that that record may have existed only for a few minutes. It does not necessarily mean record energy production (conversion) for the day. That is where the media lack of understanding distorts reality.
I am glad Maxwell's equations are helpful to you but they don't help the average guy trying to figure out the difference between power and energy.
Yes, I am a big fan of Bill Beatty. He is not afraid to shake things up. The most important thing he says is that terminology is important. This is especially true when teachin. We so easily toss around terms such as current, power, energy that the kids have no real concept of yet. One of his pet peeves is to say that current flows. Sounds good to most of us since we understand what it means. But to a kid, there is this thing called 'current' and if 'flows' in wires. Sort of like 'water' that 'flows' in a river. Then we mention 'charge' and tell them that 'flows' in the wire. Oh, so charge IS current since they both flow?? That's what it sounds like to them. That is when they shut down since the language is not consistent.
I make sure to always say 'charge flows' and 'there is a current in the wire'. Just as we would say 'water flows' and 'there is a current in the river'. Sounds picky to us, but the kids appreciate the consistent use of the language.
I like these quotes:
"Lest you think that I am quibbling over minor points of language, I note that in my experience many of the misconceptions people harbor have their origins in imprecise language... Precise language is needed in science, not to please pedants but to avoid absorbing nonsense that will take years, if ever, to purge from our minds."
- Dr. Craig F. Bohren, from his "Clouds in a Glass of Beer:
Simple experiments in atmospheric physics"
"(language) becomes ugly and inaccurate because our thoughts are foolish, but the slovenliness of our language makes it easier for us to have foolish thoughts." - George Orwell
"The search for the MOT JUSTE is not a pedantic fad but a vital necessity. Words are our precision tools. Imprecision engenders ambiguity and hours are wasted in removing verbal misunderstandings before the argument of substance can begin." - ANONYMOUS CIVIL SERVANT (from Roget's Thesaurus Webpage)
"Many errors, of a truth, consist merely in the application of the wrong names of things." -Spinoza
The current travels on the surface of the conductor rather than the cross-sectional area. Current density is closer to the measurable phenomenon. You might enjoy of good series in the Philosophy of science, studying the etymology of the terms used to express physical phenomenon and their historical progress in differential math.
The Poynting Vector might provide better insight, after one memorizes Maxwell's Eqns in differential and integral format.
". . .said they generated a current equal to roughly four times all the electrical power on Earth."
Actually, this kind of current has been generated before when I accidentally scraped the tinfoil on a gum wrapper across my silver filling.
It still wouldn't run my notebook computer for more than two hours.
Not usually. I know there is such a thing as the skin effect, but that applies not to DC or low frequency AC but to high frequency AC. DC current travels through the whole conductor, otherwise, instead of using big fat jumper cables, we could use a plastic hose with a thin coating of copper. I would suggest making such jumper cables and trying them out! Wear goggles since the copper will probably evaporate in a flash. Even for 60 Hz AC the skin effect is minimal. I know some transmission cable has a non-copper core, but this is for strength. Assuming 60 Hz transmission, skin effect is small. Yes, for high frequency signals, you CAN use hollow copper pipes.
You might enjoy of good series in the Philosophy of science, studying the etymology of the terms used to express physical phenomenon and their historical progress in differential math.
I had some of those courses years ago while I was majoring in physics. Teaching high school, I don't really get to stay in touch, even in the AP class, although we do uses diffeq for air resistance, and charging and discharging of capacitors. We do look at Maxwell's in terms of diffeq but really don't get deeper than that since it is an intro class.
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