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Showing posts from May, 2011

Fermi Solution: Settlements in Space

Congratulations to Garystar who came up with just about the same number we did for Friday's Fermi Problem soultion! Garystar, please send us your mailing address to physicscentral@aps.org and we'll send you a prize package of some Physics Central goodies!

As a reminder, on Friday I posed a Settlements in Space Fermi problem based on the painting below of a fictional space station called the Stanford Torus. By guessing the dimensions of the station in the painting below, how many of these torus-shaped space stations would we need to house all of the people on Earth? Here's the solution:

[Rick Guidice's painting of the Stanford Torus space station was commissioned by NASA in the 1970s. Think you'd like to live there? Photo credit: NASA]

After eyeballing Rick Guidice's painting above, I assumed the diameter of the entire Stanford Torus space station was 1 km while the diameter of the interior of the 'doughnut' was 50 m. Since people and houses are seen only o…

Friday Fermi Problem: Settlements in Space

What if something happened to our planet that rendered in inhabitable? We used up all of our resources, let's say. Or for whatever reason we feel the need to abandon our terrestrial home and settle in space. What would that new home look like?


Above is a painting done in the 1970s by an artist named Rick Guidice. The painting, commissioned by NASA, depicts the imagined Sanford Torus. It's a doughnut-shaped space station that rotates to provide Earth-like gravity for its inhabitants.

Here's today's Fermi question: Let's say we built the Sanford Torus for real. (It looks like a nice enough place to live.) Using the painting to guess the dimensions of the station and the settlements inside, how many of these stations would we need to house all of the people of the world?

Corked Bats, Juiced Balls and Humidors

No one should cheat in baseball . . . but if you're going to, you might want to read a recently published paper in the American journal of Physics first.



I think it's safe to say that no sport has been the subject of more physics analyses than baseball. Robert Adair's book The Physics of Baseball is now in its third edition, and remains one of the most popular "Physics of . . ." books on the market.

Adair did a great job analyzing statistics and baseball phenomena, from the challenge of getting a hit to the ideal path around the bases. For the most part, Adair relies on insightful applications of theory to the sport and breakdowns of actual baseball stats. Sometimes, though, to learn about baseball, you're gonna have to hit a few balls.

If you're a careful physicist, however, you don't actually swing the bat - that's too inconsistent. Instead you design a system that makes your experiments as repeatable and consistent as possible. That's exactly …

Physics Spinoffs

Sometimes the best discoveries are the ones you aren't looking for.



There's a physicist in Washington today. That's not terribly uncommon, but Steve Gass isn't here to warn us of global warning, beg for research dollars, lobby for/against nuclear power, or many of the other common reasons scientists talk to politicians. He's here to save the fingers of countless shop teachers and wood workers with his invention called the SawStop. Words can't do it justice, so you'll have to check out the video above to see what the Sawstop does.

We featured Steve on Physics Central years ago because we thought it was cool that he would come up with something so useful, which really had nothing to do with his research. Even though it wasn't a physics project, Gass used the problem solving skills and lab experience he gained by studying physics to come up with something so impressive that Consumer Product Safety Commission is advocating that it be included as standard…

When air just isn't good enough

While munching on my Cheerios yesterday morning, I learned from reading the cereal box that NASCAR teams fill their tires with pure nitrogen gas, instead of regular air. (I also found a toy car prize inside the box which exponentially improved my Monday.)

NASCAR teams aren't the only ones to pump up their rubber with pure nitrogen. The gas is also used in bicycle tires on the Tour de France, in Formula 1 car tires, Space Shuttle orbiter tires and some aircraft tires.

But why nitrogen? What's wrong with regular old air?

To understand why it matters what gas is used in a tire, we have to learn a little about pressure first. Tires are designed to operate under a certain pressure in order to support the vehicle they are carrying. The tire pressure is determined by the amount of air (or other gas) filling the tire. It is measured in psi - pounds per square inch.

An under-filled tire will sag on the ground, creating lots of friction between the tire and the road surface, making it hard …

Maurice Goldhaber: A lifetime of physics

Maurice Goldhaber, an Austrian-born American physicist who helped establish the standard model of particle physics and a former American Physical Society president, died at his Long Island, N.Y., home on May 11. Goldhaber was 100.

[Maurice Goldhaber in 1937.]

Goldhaber's studies of subatomic physics helped to establish the standard model of particle physics. In 1934, he and his colleague James Chadwick made the first accurate measurement of the mass of a neutron. Chadwick had first discovered the neutron in 1932. Back then, scientists thought the neutron was a combination of a proton and an electron. The measurements helped show that it is a distinct particle.

Goldhaber also contributed to the understanding of particle spin. Scientists once believed that the spin of a particle would go clockwise as often as it would go counterclockwise. Goldhaber and his colleagues showed in 1957 that neutrinos spin only in one direction. Neutrinos are those elusive particles that zip through matter…

The Physics of Blue Jeans

They're a casual Friday staple. Your dad wears them and your mom wears them. Even babies wear them. They're the uniform of the American teenager. They're blue jeans.

[Jeans are so popular, designer labels are sometimes counterfeited, as seen here. Whether counterfeit or legit, there are some that say the only way to clean your fashion jeans is to freeze them. What does physics have to say about that? Read on to find out. Photo credit: Ben Donley]

Did you ever stop to consider the physics behind this ubiquitous garment? If not, then lucky you! Today, we've done the work for you:

Saddle-wear

Jeans are no stranger to the saddle, being the popular choice for cowboys for decades. The saddle point, a shape known well to mathematicians, is when an object looks like a saddle, curving up in one direction (along the x-axis, if you're a math person) and curving down in the other direction (the y-axis). This can easily be seen in the shape of a Pringles potato chip.

Blue …

The Spacerock Saga

Imagine you are hurtling through space at 26,000 miles per hour. You're zipping along, but to you all seems still and peaceful. The stars are so far away they appear stationary and you have no sense that you are crossing the distance of Manhattan every two seconds. Everything around you is black. Darkness cloaks you and it's colder than the arctic on the worst of days.

Ahead, there is a small blue sphere. It glows brightly, silhouetted by the dark background of space. Each day, it grows a little larger and soon you realize you're on a collision course. It is called Earth, and you're headed for a land that will one day be known as Arizona.
[The Meteor Crater, as seen from about 35,000 feet.]
You are a meteor, made of nickel and iron. Once you were a part of the asteroid belt between Mars and Jupiter, but a collision half a billion years ago set you free, ejecting you into the solar system where you've been going it alone ever since.

Eventually, Earth looms before you an…

Can Killing Trees Save the World?

Here's my solution to yesterday's Fermi problem.

Just to remind you, I'm trying to determine whether it's possible to rely on trees to capture carbon from the atmosphere rather than developing technology to do it. Of course, once a tree pulls carbon dioxide out of the air, you'd have to get rid of the tree in some way that keeps the carbon locked up. (You can't burn it or let it rot, because that would just send carbon back into the air.)



The average US household produces about 7.5 tons of carbon dioxide. That's a bit under 7000 kilograms.

Carbon dioxide consists of one carbon atom and two oxygen atoms. Carbon is a bit lighter than oxygen, and only about a fourth of the carbon dioxide mass is due to carbon. So the average family is responsible for emitting

7000/4 kilograms of carbon = 1740 kilograms of carbon

Which I'll round up to 2000 kilograms to make the math easy . . .

Now, wood is mostly carbon. Precisely how much is carbon, I don't know, and bec…

Save the Planet - Kill a Tree

Fermi Problem Friday Wednesday


Capturing carbon dioxide from the air would be a terrific way to reduce the causes of climate change, if we ever find a way to do it effectively. Then you could waste all the gas you wanted, leave the air conditioner on 24 hours a day, eat meat imported from halfway around the globe, and still sleep peacefully in your drafty house with single-pane glass and uninsulated attic. Sure you'd be throwing away lots of money, but that's your right, as long as you don't ruin the rest of the planet while you're at it.

Unfortunately, according to a study by the American Physical Society (note: Physics Central and Physics Buzz are produced by the APS), all the carbon capture technologies we know of are way too expensive to be useful today. Best estimates are that it would cost about $600 per ton to collect carbon dioxide from the air. Considering that the average US household produces 7.5 tons of carbon dioxide a year, that's $4500 every family wou…

Looking for Hydrocarbons - "Physics Answers These Questions"

As I wrote in an article in APS News, physicists play an integral role in the oil and gas (O & G) industry. Oil is not sitting under the ground in pools waiting for a pipe to suck it up to the surface. It exists in the microscopic pour spaces between rocks, in areas mixed with water and sand. How do you find this oil and extract it safely through an eight inch bore hole? “Physics answers these questions and gets the oil out,” stated Brian Clark, a physicist and Fellow of Schlumberger, a leading oilfield services provider.

At the APS April Meeting, Clark and two of his colleagues in O & G research discussed the latest technologies designed to locate hydrocarbons and access the liquid gold. Clark noted that as a hole is drilled, the “drill pole” (essentially the long “stick” that has the bit at the end) actually contains a series of “laboratories” or tools, to analyze the underground environment. Each tool may look at or use different techniques to examine what is in the space ne…

The oil-water-alcohol density timer!

Each year in May the American Visionary Art Museum in Baltimore, Md., hosts the Kinetic Sculpture Race - a race of human-powered sculptures that winds around (and in) the Baltimore harbor. For the second year in a row, the APS Physics Central team built a physics-themed timer for two of the race-day events, the water and mud obstacles. This year, the team was inspired by the mesmerizing display of water interacting with oil.

[Some of the sculptures in action at the 2011 Baltimore Kinetic Sculpture Race.]
To understand why this is so cool, you might first need a little background on density. Here is a Physics Central Physics@Home explanation of the interaction between water and mineral (baby) oil:
Density is the amount of stuff you have in a given space. Something that has a high density means that there is a lot of stuff in the space, where as something with a low density has less stuff in the same amount of space. Objects with a higher density sink when compared to objects of a low…

Physics on the Disneyland Express: There are lots of large worlds after all

My continuing mission is to bump into and engage scientists everywhere I happen to go. The airplane, believe it or not, has produced many such encounters. For some reason, I just happen to always sit next to someone in science or engineering. Case in point: my famous Milan to JFK flight, on which I was not even supposed to be, yielded a seat next to a verbose Italian computer scientist. We talked shop in English and Italian for 6 of the 8 hours we were airborne.

So last week as I prepared to leave the APS April Meeting, held mere blocks from Disneyland, I wasn’t too surprised to see a bushy-headed physicist (I knew he had to be one) get on our bus to LAX. The bus was affectionately called the Disneyland Express and after I began chatting the fellow up, it became the happiest place on Earth.

This physicist was actually an astrophysicist, and was far from shy. He was so excited to talk about his research, he was practically goofy. (Please don’t groan – this post contains puns which are ob…

Writing Science Fiction: Trying to Avoid “The Button” (Physics in Hollywood, Part 2)

In the future, which may include mean aliens destroying our planet and us migrating to another world, or wacko aliens eating our brains and completely obliterating our existence, or warm and fuzzy aliens who want to “friend” us on Facebook, there will be problems. Mo’ aliens, mo’ problems, as they say.

But in science fiction, when writing about the future, while you may not want to shun aliens, you definitely want to avoid “the button”, said Bill Prady, Co-Creator and Executive Producer of the TV hit “The Big Bang Theory”. He spoke at a session at the recent APS April Meeting about one of the biggest problems in scifi – “if there’s a button that solves everything [say on a spaceship or in an underground bunker of the future], there’s no conflict,” and conflict, of course, is what makes all forms of fiction interesting.

So whether you are writing much delayed fan fiction for Star Trek or Star Wars, or a script for the newest blockbuster concerning beautiful physicists who are also secre…

Facebook and Forest Fire Prevention

Less is more when it comes to preventing forest fires, according to a new analysis that explains why aggressive fire fighting in the US may make the risk of severe forest fires worse.


Many people have speculated that land management policies in the US could be contributing to the severity of wildfires that seem to plague the country's broad swaths of wilderness each year. The argument is that routinely putting out small fires leads to the accumulation of unburnt fuel - leaves, sticks, and fallen trees - just waiting for that one, big, late season fire to come along.

A new model presented in a paper published in the journal Physical Review E shows that it's not so much the amount of fuel that's the problem, but instead the connections between flammable areas that are to blame.

University of California researchers (Mark Yoder, Donald Turcotte, and John Rundle) studied forest fires in the same way that other researchers study the flow of rumors through Facebook connections, or…

Phriday Fizzicts Phun!

Here's some Phriday Fizzicts Phunnies for you. Know any good ones? Leave them in our comments section below!

A Higgs Boson walks into a bar. The bartender looks up and says "Hey! You just missed some guys who were in here looking for you!"
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Erwin Schroedinger is driving down the autobahn when he gets a flat tire. He pulls over to the shoulder and inspects the damage. As a theorist by trade, though, he's not sure how to change a tire. Many hours pass before a police officer shows up to help. Looking for the spare, he asks Schroedinger to pop his trunk.

Policeman: "Did you know you have a dead cat in here?"

Schroedinger: "Well I do NOW!”
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Q: Who was the first electricity detective?
A: Sherlock Ohms
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Q: Where does bad light end up?
A: In a prism.
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Does a radioactive cat have 18 half-lives?
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In Munich, there's a sign that says, "Heisenberg might have slept here."
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(So old, yet so good...)
Two atoms are walking down the street. One stops and e…

Q and A with Q, et al re: Physics of Hollywood, Part 1

One of the unique benefits of holding the APS April Meeting in Anaheim, California, is that the city is just down the road from LA. A tertiary, confidential, semi-reliant “informant” specifically told me that he/she estimated that the likes of Tom Cruise, Samuel L. Jackson and Madonna had all expressed a grand desire to attend the conference, but unfortunately their schedules did not permit them to do so. However, despite their absences, the close proximity to Tinsletown did provide the impetus for a very clever set of sessions about the physics of Hollywood and an appearance by a few other celebrities.

Bill Prady, Executive Director and Co-Creator of the TV show, “The Big Bang Theory,” Bruce Miller, Executive Producer of the show “Eureka,” and John de Lancie, who played “Q” on “Star Trek: The Next Generation” participated in a plenary session entitled “The Physics of Hollywood”, which was emceed by Jennifer Ouellette, science writer and former executive director of the Science and Ent…

Mystery Force May Be Due To Mirrors

40-year old NASA space probes are still heating up the field of astronomy after identifying mysterious 'anomaly'.

[Photo credit: NASA]

Portuguese physicists report that they have identified the unknown force whose influence on outward bound interplanetary space probes has puzzled scientists since 1998.

Until now, theorists speculated that this "Pioneer anomaly," -- affecting NASA's Pioneer 10 and 11 -- is caused by unseen matter in space, the gravity of an unknown planet, or even new principles of physics: beyond even Einstein's theory of general relativity.

This anomaly is one of a long line of mysterious motions in our solar system, many of which were resolved when investigators discovered new objects or physical effects.

Case in point: In the 19th century, Uranus deviated from its calculated orbit and the gravity of an unknown planet was suggested as the cause. In 1846, the discovery of Neptune solved the mystery. Astronomers blamed a quirk in Mercury's or…

New possible signal of dark matter subject of debate

Dark matter detection experiment CoGeNT has seen a possible signal of dark matter, similar to the much-disputed DAMA/LIBRA collaboration result, it's spokeperson announced yesterday at the American Physical Society April meeting in Anaheim, California. Whether or not it is really a sign of dark matter is still very much open to debate but it presents an intriguing possibility that is leading to heated discussion in the dark matter community.

The germanium detector at the heart of the CoGeNT dark matter  detector. Photo courtesy of the CoGeNT experiment.
CoGeNT spokesperson Juan Collar presented data that showed an excess of low energy interactions in their germanium crystal detector that couldn't be explained by any known cause. Something seems to be hitting the germanium atoms and making them recoil. That something is a mystery, but possibly dark matter. The hits are coming at a rate of about 3 per day which is higher than expected based on other dark matter searches but is sti…

Sights from the APS April Meeting

Here are some sights from the APS April Meeting held Sat., April 30 through Tue., May 3 at the Hyatt Hotel Orange County in Anaheim, Calif.Research on nuclear physics, particle physics, and astrophysics among other topics was presented at the meeting.

[Peace, love, and neutrinos: One researcher handed out buttons related to her research at the APS April Meeting held April 30 through May 3 at the Hyatt Regency Orange County in Anaheim, Calif.]

[Physicists stroll through the lobby of the Hyatt Regency Orange County, site of the APS April Meeting.]

[A large crowd filled the room for the meeting's first session celebrating 100 years of sub-atomic physics. Topics included the Large Hadron Collider and the search for dark matter.]

[Benson Way, a graduate student at the University of California, Santa Barbara, reads through the schedule of APS April Meeting events.]

[The APS April Meeting spanned the weekend of April 30 and included research on nuclear physics, particle physics, and astroph…