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Comment Re:Bah (Score 1) 564

Really? Prove Newton's Second Law. Oh wait, you can't, because no proof exists, it makes sense and has seemed reasonable for 400 years, but there is no objectivity in physics or any other tech. Based on a set of assumptions (vector arithmetic, Newton's three laws, various other definitions) this is how the world works. Tech is much much more subtle than you think. You seem to be parroting the professor too much

Comment There are requirements to list books and prices (Score 5, Informative) 396

But there are requirements to list books and prices! The federal Higher Education Opportunity Act requires colleges and universities to make public lists of books and other materials that will be required for each course by the time of students are expected to enroll in those courses. This was supposed to drive down the cost of textbooks because it will give students more time to find online prices. As a professor, I haven't noticed much of a change since this law took effect in July 2010, the prices in the bookstore are still outrageous.

Comment Hydrogen Spectrum! (Score 1) 350

As a physics professor, I must suggest that you test this with a hydrogen spectrum and a diffraction grating. You may remember that each element has its own "spectral fingerprint" of wavelengths of light that it emits when excited. Several of the spectral lines for hydrogen are in the visible spectrum, 656 nm (red), 486 nm (cyan), 434 nm (blue), 410 nm (indigo), 397 nm (UV). I've only ever seen the first three, my eyes aren't sensitive to the 410 nm light (plus it's fairly weak) . If you really have UV-sensitive eyes you should see the 410 nm easily and even the 397 nm light. Good luck!

Comment Re:College is more than listening to a lecture. (Score 2) 261

As a college professor, I must disagree with both of your points.

I would love to use open textbooks and each summer I spend time looking them over, only to be disappointed in the quality of the text, the illustrations, the problem statements, the equations, the photographs, the grammar and the overall organization of the book. Writing an introductory physics text is hard. Most of the texts on the market have been around for twenty or more years and have been substantially revised by large groups of authors. If I could spend my "free-time" and write an intro physics book and publish it using copyleft, I would. I work hard to find textbooks that are inexpensive, I use Dover books or similar when I can if there is not something free. I tell my students about discount sites and that they are under no obligation to buy books from the bookstore. I try to keep the cost of books for each semester per class less than $80.

It's not just me, most of my colleagues would use free books if we could. Remember, college professors are all about freedom of thought and ideas. I can't imagine a professor that would want to lock down your ideas.

The only time I had a class where the professor wrote the textbook, he distributed it to us for free. The college as a whole sees very little money from the college bookstore. In most every case, college bookstores are no longer owned by the college, but run by a for-profit national business (usually Barnes and Nobles). The college gets rent and some money from marketing t-shirts and the like. The profit goes to the national bookstore and the publishers.

Comment Re:Holy misinformation, Batman. (Score 1) 1017

As a physicist that studies medical ultrasound, there actually ARE radio waves emitted by a ultrasound scanner. The scanners uses a high frequency electronic signal to excite the transducer that creates the pressure waves. When the electronic signal travels through the wires some of the electrical energy is converted to radio waves, just as in any antenna. In fact, I use this radio signal as a "trigger" for acquiring information about the scanner; using a small coil of wire near the transducer, you can pick up the radio wave quite easily.

I'm really impressed that the TSA knew this. Someone must have been thinking about ways to claim that terahertz radiation is safe for children.

Comment Fox News Errors?? (Score 1) 1855

So for kicks I flipped the channel to Fox News, here's two things I noticed
1) they consistently report that the raid happened a week ago and the "U.S. has been waiting for DNA evidence that it really is Usama bin Laden"
2) they consistently report that the raid took place "on the outskirts of Islamabad, the capital of Pakistan"

Hearing the President's speech, I find no evidence for either of these, how can a news organization get the time and place of death wrong when the President announced it less than a hour ago?

Comment Re:Sounds like liberal arts grad students (Score 1) 332

You mean humanities not "liberal arts".

As a professor in physics at a liberal arts college, you mean "humanities" not liberal arts. Liberal arts ultimately refers to the seven subjects taught at colleges in the Middle Ages and includes literature, languages, philosophy, history, mathematics, and science. Liberal arts is the idea that students should be well-rounded and not prepared for any one vocation. It is the exact opposite of what you mean. Please stop using the wrong term.

Comment Re:Cute, but not accurate (Score 1) 392

As a medical physicists, I must point out that this comment is wrong. The sievert is the unit of "dose equivalence" used in medical and health physics. It is based on the gray which is defined as 1 joule absorbed per kilogram. The sievert and gray have nothing to do with time but with mass.

The human body can repair damage from radiation. In fact, it has to, think about the cosmic rays hitting your body each day. But it takes time to repair damaged DNA or organelles. If the damage happens too fast, the damage can become irreparable.

Comment Memories... (Score 1) 236

I was in fourth grade, Mrs. Cook's class. My class was not one of the ones that got to go to the library to see the launch on television. The class troublemaker, Michael, had gone to the library on a hall pass. He ran into the room, yelled, "the space shuttle just blew up" and the teacher calmly said, "Michael, you stop lying this instant or you will get a paddling." Five minutes later, the principal came on the school's PA system. My teacher just started crying.

Comment Bad bad article and summary (Score 5, Informative) 58

As a physicist that works with radionuclides, I'm appalled at this article. It is horribly written. "The crystal vibrates in a certain way" made me laugh.

A better summary is provided by OSU public relations dept at

Radiation detectors have been digital for a long long time. Some of the electronics has been analog because analog electronics are faster and always will be for filtering and integration.


NASA Tests Flying Airbag 118

coondoggie writes "NASA is looking to reduce the deadly impact of helicopter crashes on their pilots and passengers with what the agency calls a high-tech honeycomb airbag known as a deployable energy absorber. So in order to test out its technology NASA dropped a small helicopter from a height of 35 feet to see whether its deployable energy absorber, made up of an expandable honeycomb cushion, could handle the stress. The test crash hit the ground at about 54MPH at a 33 degree angle, what NASA called a relatively severe helicopter crash."

Comment Re:Very cool, but... (Score 5, Informative) 152

Actually, as a researcher in the field, controlling cost is one of the motivations behind this method.

Do you have any idea how much open brain surgery costs? It's several days in the hospital, plus a team of surgeons, plus an operating room. All in all, from $50,000 to $200,000. High intensity focused ultrasound (HIFU) doesn't need any of that. There are hopes this could almost be an outpatient type of procedure.

One my childhood friends suffered from epilepsy for many years until as a teenager, he had exploratory brain surgery (in 1988) where they removed a cubic centimeter of diseased tissue. He was in the hospital for a week.

Not every new idea in medicine costs more money.

Comment Re:A big medical breakthrough. (Score 1) 238

Actually current CT's are designed to use a "cone beam" and measure radiation from as much area as possible at one time. This has allowed the time it takes for a CT scan to go from minutes per slice to tenths of seconds per slice. Unless you had hundreds (or thousands) of pencil beams, the current scanners would take much less time.

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