Category Archives: Journalism

Fuelish

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World’s first battery fuelled by air

I don’t think so. No more than your car is fueled by air when you have combustion. The difference is between carrying around oxygen in the cell, and drawing some oxygen in from the air in order to complete the reaction and release energy.

If you go to the group’s website, they explain the basic process:

On discharge, Li+ from the electrolyte and e- from the external circuit combine with O2 from the air, the process is reversible.

The big win is not carrying around Oxygen, which is more than twice as massive as Lithium. There’s also carbon and a catalyst involved, but of course a catalyst gets reused, and so you don’t need a stoichiometric fraction of that present. In the article at Green Car Congress it’s mentioned that the catalyst is Mn.

The Guardian article also claims

And as the cycle of air helps re-charge the battery as it is used, it has a greater storage capacity than other similar-sized cells and can emit power up to 10 times longer.

I see nothing supporting the claim that any kind of recharging is going on.

No, He Didn't

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Am I on the ring road? Stunt driver defies gravity on the world’s biggest loop-the-loop

He didn’t defy gravity — I’m sure it was there the whole time.

If stuntman Steve Truglia had been too timid in his acceleration, his yellow Toyota would have reached the top of the track and dropped like a stone.

Not quite. If his speed was insufficient, he would not have reached the top. But the car would have dropped like a stone.

The Toyota had to be travelling fast enough that the centripetal force generated by its circular motion ‘offset’ the downward pull of gravity. This required the stuntman to enter the loop at exactly 37mph, immediately change out of gear and slow to 16mph as the vehicle swung round the top.

Well, no. The centripetal force is the gravitational force in the limit of the slowest speed that allows you to complete the loop, and the speed will naturally decrease as kinetic energy is converted to potential energy. Since the loop is 40 ft tall, we can actually calculate this. An object entering the loop and rising 40 feet to be traveling at 16 mph must be going 38 mph as it enters. The article says 37, but car is a little off the ground, so the actual change in potential energy is smaller. (The actual change in height is 37.4 feet using those numbers, putting the CoM a little over a foot off the ground. Close enough)

The downshifting isn’t there to slow the car down — the only thing the engine needs to do is compensate for losses. The downshifting is because the car will slow down, and you don’t want it to stall as the result of being in the wrong gear. An ideal car (of which a Toyota does not qualify) could simply coast after entering the loop. It’s entirely possible to enter the loop at a slower speed, but have the engine make up the additional energy needed while in the loop, but that would not have been the safe move from the he-doesn’t-so-much-loop-as-plummet angle .

And, from a physics point of view, he could have gone faster. 16 mph gets you about 1g of downward acceleration, i.e. you are basically in freefall under that scenario. The numbers don’t quite jibe — even when I use the smaller radius from above, the acceleration is a little lower than 1g. So undoubtedly some rounding went into the story already. Going faster would just mean that the track was exerting some force on him while at the top.

As far as the danger of blacking out, that’s why he wanted to be going near the minimum speed at the top, because near the bottom is where he would pull the most g’s — about 5 of them, at that speed, assuming the track is circular and not flattened to reduce the force.

Is it Illegitimate Journalism?

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The Daily Show as Legitimate Journalism

Jon Stewart makes no pretense that he’s all about the entertainment, but I think the article is right — he does ask the tough questions when the time comes and shows good insight into issues.

The venerable Sunday morning news shows, oftentimes featuring some of the most reputable people in journalism, largely go through a formulaic process, repeated weekly with their guests. The crack team of researchers will provide a number of quotes made by said interviewee appearing to contradict each other that the guest will then evade and stonewall against by jumping through any number of grammatical, contextual, semantic, and logical hoops. While The Daily Show has a more varied roster of guests from week to week, the Sunday morning talk shows routinely have decision makers and opinion leaders on to explain themselves. Put it this way; who would you rather have interview David Addington, Alberto Gonzalez, Donald Rumsfeld, or Dick Cheney? I would feel much more confident that an interview with Stewart would reveal more of a subject than an interview with any of the Sunday morning hosts. If British talk show host David Frost can cement the legacy of a disgraced U.S. president, then certainly Jon Stewart would be able to shed light on some of our more pressing national issues.

I’m guessing that some of the people mentioned would rather only be interviewed by someone who was tossing slow pitches over the fat part of the plate

What an Entangled Web We Weave

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Even if we don’t practice to deceive.

zapperz has a post up which points to an article in the WSJ on quantum entanglement: Science, Spirituality, and Some Mismatched Socks

zz marks it as a good layman’s review, but I don’t agree.

Stranger still is entanglement. When two photons get “entangled” they behave like a joint entity. Even when they’re miles apart, if the spin of one particle is changed, the spin of the other instantly changes, too. This direct influence of one object on another distant one is called non-locality.

This is a common summary of entanglement, and it’s wrong. The entangled particles are in indeterminate states — the only thing you know is that the states have a particular relationship, e.g. one is spin up and one is spin down, or the polarizations are perpendicular, depending on how you entangled them. But the notion that one of the particles has a definite state before it’s measured is a classical interpretation, not a quantum mechanical one, and that’s where the analogies that are often used fail to work. That is, a particle prepared in this fashion does not have a state until it is measured — the state of the particle does is not “hidden.”

So if you don’t know what the state of the particle is, you can’t say that it has changed. What you can say is that when you measure the state of one particle, you instantly know the state of its entangled partner, but at the instant you do this measurement, the particles are no longer entangled. Further interactions affecting that attribute will result in no effect on the other particle. And I think this is where the quantum wheels come off the wagon, because this classical misconception has not been dispelled. There’s still this idea that the two particles communicate, and do so instantly. The description given gives the implication that this is so, and then you have the contradiction when you are told that faster-than-light communication isn’t possible with entanglement.

The amusing story of Bertlmann’s socks harms the explanation.

Mr. Bell noted that if he saw one of Mr. Bertlmann’s feet coming around the corner and it had a pink sock, he would instantly know, without seeing the other foot, that the second sock wouldn’t be pink. To the casual observer that may seem magical, or controlled by “hidden variables,” but it was no mystery to Mr. Bell because he knew that Mr. Bertlmann liked to wear mismatched socks.

For the story to work properly you have to also include the notion that which foot was sporting the pink sock wasn’t known until you measured it. All you knew was that one foot had a pink sock, and that if you measured it on Mr. Bertlmann’s left foot, you cannot say that it was on his left foot at any previous point. Thus is the weirdness of quantum mechanics and entanglement.

My take is that any article that puts forth such a basic misconception can’t be a good layman’s guide.

A better treatment

Perpetual Energy. Film at 11.

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Physics Buzz: Free Energy and the Press

Harlow mentions in passing that “Many scientists say the technology violates the basic laws of quantum physics.”

Really, such a sentence is tantamount to saying “It doesn’t work.” Unfortunately, that was lost on Harlow, who continued reporting as if the laws of physics could be changed with a simple majority vote in the local town council. Simply put the Universe doesn’t work that way. The problem here was this report aired at the same time that CNN announced it was closing down its entire science bureau.

Physics Malpractice

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Via physics and physicists I see a story about how golf can be hazardous to your hearing. And the story botches the physics. (I don’t know if it’s the journalist or from the original journal article)

The coefficient of restitution (Cor) of a golf club is a measure of the efficiency of energy transfer between the golf club head and the golf ball. The upper Cor limit for a golf club in competition is 0.83, which means that a golf club head striking a golf ball at 100km per hour will cause the ball to travel at 83km/h.

Well, that’s just wrong. The Cor tells you about the kinetic energy, so it won’t be the same for the speed, because KE depends on v2. i.e. if a ball is dropped from 1 meter and bounces, returning to 0.83m, the impact speed is ~4.4 m/s and the return speed is ~4.0 m/s, which is 0.91 of the speed.

Another problem is that the mass of the clubhead is not the same as the mass of the ball. Even if the Cor applied to speed, the statement is incorrect. In the limiting case of Cor=1 and the ball’s mass being negligible, the ball would leave at twice the clubhead speed.

The actual equation is v = u*(1+e)/(1+m/M)

v is the ball’s speed, u is the clubhead speed, e is the Cor, m is the ball’s mass and M is the clubhead mass. (This is trivially derived using conservation of momentum and balancing the kinetic energy equation to account for the loss) Using e = 0.83, and assiming the M=4m, we see that v = 1.46u

Update — This is using a definition of Cor on terms of energy. I couldn’t find how the USGA was defining it when I was composing the post, but further research (and noted in the comments) indicates that it is indeed the fraction of the speed retained after the collision. That changes the details of the analysis, but the article’s numbers are still wrong — the ball’s speed is larger than the clubhead speed. I still haven’t found a mathematical definition of how the USGA applies this to a golf club

That makes e in the equation the square of the Cor (so e = 0.689), which means that the ball leaves the clubhead at v = 1.35u

Thinking in Two Dimensions

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A correction from an LA Times story editorial

Solar power: A Friday editorial said that according to the U.S. Energy Department, enough sunlight hits a “100-square-mile” portion of the Nevada desert to power the entire country. It should have said “100-miles-square.”

The commentary: On square miles

I’d argue that “square miles” and “square kilometers” really have no place in popular journalism, because we have little connection to what they mean.

As humans, we never travel a “square mile.” We travel a mile. Or ten miles. If we’re thinking about an area of land, we’re probably mentally walking along two of its edges — which is what the LA Times and the U.S. Department of Energy were doing.

What you mean “we?” While the statement may be true (for some people), I’d argue that it’s an issue of mathematical/scientific literacy. Eliminating the use of area is to lower the bar of what we expect of journalists and readers of journalism. I never travel a cubic meter, either, but use of volume has its place — we don’t need to describe a liter as 10 cm on a side. We’re used to volume measurement, even if we in the US have an overall aversion to metric except when applied to some beverage containers. Why aren’t we used to areas — is it the name? Would “acres” be better, to avoid the “square” business?

The proposed solution includes giving an example, though, and giving a reference for scale is a good idea.

Ideologyspotting

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How to spot a hidden religious agenda

Misguided interpretations of quantum physics are a classic hallmark of pseudoscience, usually of the New Age variety, but some religious groups are now appealing to aspects of quantum weirdness to account for free will. Beware: this is nonsense.

UPDATE: As the comment below indicates, the article was pulled. PZ points out that there is an archived copy of the article

I think it’s sad that NS would cave to complaints, rather than having some intellectual integrity. There was no malice in the story. Occasionally the truth is going to force some people to open their eyes a little, and that can sometimes be painful.

It's Pure … Something

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Tiger Woods’ game after surgery may be pure physics

Woods’ swing has been the envy of golfers around the world ever since he burst onto the professional scene in 1996.

His action is pure efficiency, combining hip, shoulder and wrist motion to exert the greatest possible force on the ball.

Pure efficiency? Does that make him the Carnot of golf. Perhaps we should refer to the swing as the “Woods cycle.”

The applied physics of his swing propels the club head at an estimated 125 mph at the point of impact with the ball but it also concentrates intense and repeated kinetic energy on his left knee.

Ooh, concentrated intense and repeated kinetic energy? That made me wince, but not from ligament damage.

Much of the rest of the article is about biology and medicine. I don’t know how badly mangled that is.

Tripe from Tierney

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I ran across Tierney’s latest post in the NY Times, Politics in the Guise of Pure Science and, as it too often does, it left a bad taste.

Why, since President Obama promised to “restore science to its rightful place” in Washington, do some things feel not quite right?

First there was Steven Chu, the physicist and new energy secretary, warning The Los Angeles Times that climate change could make water so scarce by century’s end that “there’s no more agriculture in California” and no way to keep the state’s cities going, either.

I couldn’t help but notice that Tierny doesn’t actually rebut the claim, or give any context at all for it. Just simple appeal to ridicule, with fragmentary quoting, which always raises the question of whether the remarks are being quoted out of context. Not to mention that I think Tierney is missing the point. There is science, and there is policy. Policy will encompass more than science, but it’s critical that policy be based on science, rather than basing policy on ideology and rewriting or suppressing contradictory science.

Via The Inverse Square Blog I see that my spidey-senses were spot-on. Siegel at Daily Kos provides more complete quotes and context to Chu’s comments, and makes it clear that Chu was describing a range of possibilities, with the loss of agriculture and severe reduction in water for the cities at the extreme end of the spectrum of outcomes.

Update: Carbon Nation takes a swipe, too.