Category Archives: Physics

Don't Make Them Feel Self-Conscious

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Weird Antimatter Particles Discovered Deep Underground

Don’t call them weird — they aren’t. They violate parity, but that makes them special. As far as I can tell (and it isn’t easy, because the press releases and web pages do a kinda crappy job of this), the so-called geoneutrinos are electron neutrinos, given off in decay chains of heavy elements in the earth’s interior. More specifically, they would be antineutrinos, since the decay chains typically involve alpha and beta-minus decays, and the latter give off electron antineutrinos.

In other words, the particle is not new. The name distinguishes them from solar neutrinos, but I think it also adds confusion to the mix, especially when the distinction isn’t made clear. Unnecessary jargon isn’t a good thing.

What is interesting is that the scientists are trying to use this as a diagnostic for learning about the earth’s interior.

The researchers hope that by studying geoneutrinos, they can learn more about how decaying elements add to the heat beneath Earth’s surface and affect processes like convection in the mantle. Whether radioactive decay dominates the heating in this layer, or merely adds to the heat from other sources, is an open question.

Totally Made Up Fact of the Day

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The seed of the idea for the Pauli exclusion principle was planted when Wolfgang Pauli and his identical twin were not allowed on the football (soccer) pitch at the same time, until the club could afford jerseys with numbers thus allowing the officiating crew to distinguish the two.

Also not well known was that their very devout sister left the church to begin a brewery.

Quote of the Day

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Comes from a discussion of vacua; an ion gauge should provide a small amount of pumping, sufficient for a small system, but in case it doesn’t, one could place the system in (or just above) some liquid nitrogen, which prompted this gem about cryopumping:

At liquid Helium temperatures, even a cheeseburger doesn’t outgas much.

(originator unknown)

The Leroy Anderson Effect

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Metronome Synchronization

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Putting them on the board allows them to couple, so vibrations from each can interfere and the most efficient energy transfer is when they are in phase. I’ve read that this trick was exploited by sellers of pendulum clocks, back in the day — by hanging the clocks on one wall, they would similarly tend to synchronize. This would give the customer the impression that all of the products were high quality clocks when that was not the case, though you could not tell from the pricetag — the poor clocks were being driven by a few good ones.

(Leroy Anderson was the composer of The Syncopated Clock)

The Worlds Most Expensive Thermometer

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The roadway across the Golden Gate Bridge rises and falls as much as 16 feet depending on the temperature. When the sun hits the bridge, the metal expands and the bridge cables stretch. As the fog rolls in, the cables contract and the bridge goes up.

There’s also a 2-hour delay because of the thermal mass of the bridge.

I'll Huff and I'll Puff

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… and I’ll push this little red button

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To be fair, the “house” of bricks is more like a wall, and without mortar. Pigs may make houses out of straw and sticks, but they follow building codes, dammit.

Puts my Airzooka to shame, though.

I Have to Issue You a Ticket

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For violating the laws of physics

Violations of conservation of energy
Count #1: The ball is traveling much faster at the top of the first loop than when it rolls down the ramp just above it
Count #2: The ball comes off the green elastic faster than when it hit

Count #3: The ball come to rest just below the rubber band, and
Count #4: again on the left on the second ramp from the bottom,

yet has enough energy to launch the next ball all the way to the top

The launching device should be a cannon triggered by a pushbutton, to plausibly add energy to the system.

(updated to add #2 and renumber other violations)

I Can Do the Can Can

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The topic of discussion a few days ago was vacuum chambers, because we want to eventually trap ions, and these can be made to be pretty compact — you don’t need a very large vacuum chamber. In fact, you can get away with no external pump at all in the final configuration; after the initial pumpdown you pinch off the connection tube you activate a getter material inside the vacuum chamber (remembering, of course to put Bedevere, Lancelot and Galahad inside the rabbit beforehand, in order to take the French by surprise. Not only by surprise, but totally unarmed!)

How compact? Well, basically the size of a soda can. Which, of course, prompted a discussion of using an actual soda can. We ignored the problems of the hole in the can and the completely inadequate strength of a can, and instead focused on the problem of whether cans had a liner that would cause a problem with a vacuum. Something easily checked by a visit to Google, but we’re experimentalists, and a hacksaw blade was closer than the internet. We empirically determined the presence of the liner. It was only later on that one of us confirmed that a liner called Vinylite was introduced in 1934; the problem that prompted the invention was that beer in cans tasted just awful. (i.e. much worse than beer in cans currently taste)

The major problem the early researchers were confronted with, however, was not strength, but the can’s liner. Several years and most of the early research funds were spent to solve this perplexing problem. Beer has a strong affinity for metal, causing precipitated salts and a foul taste. The brewers called the condition “metal turbidity”.

Though I would not have been surprised if it read “causing precipitated salts and a foul taste. The brewers called the condition Genesee Cream Ale”

Along with that tidbit is a recipe for dissolving the aluminum to leave only the liner. It involved 6M KOH, so this is not something you want to try at home.

Inside the Soda Can

Get Your, er, Buns to Mars

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Seventh Graders Find a Cave on Mars

On their two targeted images the students found lava tubes, as they had hoped. And on the backup image, they also found a small, round black spot. Many Martian lava tubes are marked by aligned chains of collapse pits, which typically have flat floors and sloping sides. The spot they [sic] students found, however, appears to have vertical sides.
…
The students have submitted their site as a candidate for imaging by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. HiRISE can image the surface at about 30 centimeters (12 inches) per pixel, which may allow a look inside the hole in the ground.

Falling Down on the Job

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Getting the drop on gravity

It’s an ingenious plan with two major problems: first, the super-cold atom clouds are extraordinarily hard to make. Second, the best way to test gravity is to make sure that no other forces are acting on an experiment. Short of launching it into orbit, the best way to do that is to drop the whole experimental apparatus so that it goes into free fall.

Incredibly, Rasel and his team have now licked both problems. They devised a special self-contained canister that can automatically generate a BEC. They then dropped the canister from the 146-metre-high drop tower at the Center of Applied Space Technology and Microgravity in Bremen, Germany.

This is one of the experiments I mentioned in a discussion of chip-scale atomic physics a while back. And while it’s hard, I don’t know that it’s extraordinarily hard — the workshop I summarized was part of a push to move this type of technology forward. You get a lot of smart people thinking about the problem, trying different things, and you find solutions. But it is hard. It’s supposed to be hard. The hard is what makes it great.

here’s another story on the topic: Scientists Drop Theory of Everything Down Elevator Shaft