Thursday, November 29, 2007

When will we see DSCOVR again?

It's sometimes terrifying, in this age of information, to realize how much we don't know. A satellite built by NASA that could answer the major questions we have about global warming, and settle disputes over the reality of man-made climate change, is gathering dust in a Maryland warehouse. The importance of the information it might have provided cannot be understated. The satellite is built and paid for, and was scheduled for launch two years ago, but for undisclosed though not unsought reasons, NASA and the federal government have kept the Deep Space Climate Observatory satellite (DSCOVR) locked away, and with it the American public's right to an answer.

It’s a slap in the face to every American citizen that the Executive Branch has denied that it should be held accountable under the Freedom of Information Act to disclose documents concerning why the DSCOVR satellite was retired before it’s first launch. NASA itself also opted to withhold all internal documents (against the FOIA), on the grounds that they wanted to protect against public confusion as to the actual reason for their actions. We’re still confused, and we should be outraged.

Prior to DSCOVR's original launch date, NASA issued no official statement, but quietly announced that the mission was canceled due to "conflicting priorities." That was after spending millions of taxpayer dollars to build it. I'm sad to say I hadn't even heard of the DSCOVR satellite until this week, thanks in part to the fact that most major news sources are playing the same quiet game as NASA and the White House (although it's not fair to take blame off myself for not being more alert). The next question was why the government would try so sloppily to cover up such a decision.

The importance of the information that could be provided by DSCOVR is emphasized by the fact that both domestic (the NOAA) and foreign (the Ukrainian government) institutions have offered to buy DSCOVR and pay for it’s launch, so that the information it can provide will be available sooner – or at all, if NASA’s plan is to keep DSCOVR under wraps for good. But to these offers NASA replied with a good kind NOTHING. There was no response, not even a polite No or explanation of why they can't bear to part with a satellite they aren’t using. Without so much as a response to the question of 'why?' it seems we can only assume the worst.

Is the government keeping DSCOVR hidden because it’s afraid of the information it will inevitably retrieve? Is there really such a huge need to keep global warming in the politically golden realm of “still being investigated”? By giving no reason as to why it wasn't launched, denying the release of supposedly free documents, the lack of response to counter offers, and NASA's total lack of comment on the situation, I feel there is little else that we can assume. Furthermore, it’s unclear if we can hope that the next administration will change this decision. It is important that people know about this. I'm begging someone to prove this wrong, particularly with news that DSCOVR is being launched.

I’ve compiled a list of articles and blogs that are writing about DSCOVR. In particular I should point out the efforts of Mitchell Anderson, who has been hounding the DSCOVR issue for more than a year and is the person who initially went after the DSCOVR documents that were denied. Here is a link to one of his articles on the topic, that summarizes the situation with DSCOVR quite well: http://www.desmogblog.com/nasa-stonewalls-
another-us-agency-that-wants-to-launch-dscovr.

Physics Buzz will be writing more on this story next month, so keep you eyes peeled, and please post any other links you find important.


DSCOVR Articles and Blog Entries:

The official NASA website of DSCOVR, not updated since 2001.
http://enso.larc.nasa.gov/triana.html

DSCOVR website through the Scripp's Institution of Oceanography (Not updated since DSCOVR's non-launch):
http://cloud.ucsd.edu/dscovr.html

White House Denies Inquiries over DSCOVR cancellation (Oct.2007)
http://www.goodcleantech.com/2007/10/white_house_denies_inquiries_a.php


Washington Post Article (August 2007)
http://www.washingtonpost.com/wp-dyn/content/article/2007/08/22/AR2007082202441.html


Important Comment on the Debate (October 2007)
http://mitchellanderson.blogspot.com/2007/10/dscovr-debacle-part-3.html


The Bush Administration and Al Gore: Where DSCOVR might fit in (October 2007)
http://gristmill.grist.org/story/2007/10/16/101926/97


Blog by a climate modeler from Argonne Ntnl Lab (September 2007)
http://climatespin.blogspot.com/search/label/DSCOVR


BBC Covers DSCOVR’s initial grounding (July 2006):
http://news.bbc.co.uk/2/hi/science/nature/5134022.stm


Scientific Paper about the uses and benefits of DSCOVR:
http://adsabs.harvard.edu/abs/2006cosp...36.1653V


Early DSCOVR blog (September 2006):
http://seedmagazine.com/news/2006/09/free_dscovr.php


One of the early DSCOVR blogs (2006):
http://www.desmogblog.com/anyone-for-a-dscovr-bake-sale



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Something to get you through the day...


I decided to do a search of all the books titled "The Physics of _______". Everything is physics, but many books give it to ya straight in specific cases. With over 300 hits, here is a list of my favorites:

The Physics of
Superheroes, Consciousness, Christianity, Everyday Life, Everyday Phenomena, Christmas, Insultingly Stupid Movies, Medical Imaging, Golf, Basketball, Baseball, Hockey, Sailing, Dancing, Skiing, Sports, Radiology, The Body, Electric Propulsion, Angels, Music, Irrigated and Nonirrigated soils, Musical Instruments, Shock Waves and High-Temperature Hydrodynamic Phenomena, Foams, Immortality, Interstellar Dust, William of Ockham, Quasicrystals, Liquid Crystals, Coronary Blood Flow, Cerebrovascular diseases, Diamond, Galactic Halos, Laser Plasma Interactions, Three-Dimensional Radiation Therapy, The Non Physical, Agriculture, Time Asymmetry, Time Reversal, Laser Fusion, The Earth’s Core, Blown Sand and Desert Dunes, Glaciers, Ice, Monsoons, Heaven and Earth, Explosive Volcanic Eruptions, Clouds, Rain clouds, Mesospheric (Noctilucent) Clouds, Atmospheres, Traffic, The Ear, Balls in Motion, Birdsong, Welding, Pocket Billiards, Sound, Flight, Viruses, Paranormal Phenomena, Eternity, and Television.


New titles I might suggest:
Babies, Wrestling, and MySpace.

Additions/Suggestions welcome.
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Tuesday, November 27, 2007

It’s Physics, My Dear Watson. -- OR -- Pyramids, JFK, and Dinosaurs


Physics can be like a universal tool kit for solving mysteries. It doesn’t come with instructions, but if you figure out how to use it you’ll find that it comes equipped with everything you need to discover whether or not an ancient pyramid has hidden chambers, how to explain discrepancies in the JFK assassination footage, or find substantial evidence that a meteor impact killed the dinosaurs. And for those who don’t know how to use the tool kit, be sure you get a detective like Luis W. Alvarez.

As reported by Phil Schewe in this week’s Physics News Update (http://www.aip.org/pnu/2007/split/847-2.html), a paper by Charles G. Wohl, published in the November issue of the American Journal of Physics reflects admiringly on the career of a true physicist. Luis W. Alvarez won a Nobel prize in 1968 for his work in elementary particle physics, but his other work stands out for it’s application to classic mysteries.


The Pyramid Burial Chambers:
The two largest pyramids ever built are in Cairo, in honor of Cheops and his son Chephren. With over 13 acres of floor space hardly being used, it boggled archeologists why there weren’t more rooms in Chephren’s pyramid. It was highly hypothesized that there were hidden chambers in the pyramid, but no clear way to find them. Luis Alvarez knew that if you pass waves or particles through a dense substance (like X-rays through your body) you can gather information about the interior structure of that substance (the X-rays bounce off your bones but penetrate flesh). If there were chambers in the pyramids, sending particles or waves through them might reveal where. Alvarez realized that X-rays would be no good through the very dense rock. So instead of blasting particles up through the pyramid, he had the idea of letting the particles come from above.

Cosmic rays in our galaxy are responsible for a shower of relatively large particles called muons raining down on us constantly. Our bodies have adapted to the barrage so as to keep us from sprouting holes. Muons are strong, but they can be partially stopped by rock. In other words, fewer muons will make it through a wall of rock than started in. Alvarez’s team put a muon detector in the main room, in the center of the lowest part of the pyramid. If there was a hidden chamber in the pyramid, more muons would show up on the detector because they met less resistance: a gap in the rock, or chamber, would allow more of them to pass through. Somewhat sadly, Alvarez’s team found no sign of hidden chambers. From Wohl’s paper:

It was a disappointment to find no burial chambers and no mmarvelous treasures. But the use of “rays” provided by nature together with the new tool of spark chambers was ingenious. And the mystery was solved. People would say to Luie, “So you didn’t find any chambers.” “No,” Luie would reply, “We found that there are no chambers.”

The JFK Assassination Video Tapes:
The immediate wave of conspiracy theories in the murder of John F. Kennedy in 1963 were often based on one seemingly disturbing fact: video footage of Kennedy being shot showed his head bucking forward, in the direction of the bullet, and then back toward the shooter. Intuition told people that his head should only move in the direction of the bullet, and that it’s motion backward suggested a second shooter somewhere on the scene that day.

Having also explored the physics of photography (what hasn’t he studied?) but really only needing basic mechanics, Alvarez thought he could explain the puzzle in the video. If a bullet strikes an object and sticks to it perfectly, the motion of the combined object-bullet will only be in the initial direction of the bulle. The bullet's momentum has to be conserved. But the energy of the bullet is changed into heat and damage to the object: so in the case of a human head, the bullet causes jets of blood and brain matter (pardon the gore) to also move in the direction of the bullet (away from the shooter). These jets also have momentum that must be conserved. So, the jets push the head back toward the shooter, causing a seemingly counterintuitive motion. It may seem hard to believe, but both mathematics and demonstrations (they used melons wrapped in filament tape) illustrated Alvarez’s point.

Alvarez did additional analysis of the film, but nothing to settle the conspiracy theories or bring us any closer to really understanding what happened that day. The paper emphasizes that even if a bullet from one direction were responsible for the motion of JFK’s head, it can't actually tell us the number of shooters at the scene. Such mysteries may remain unsolved.


The Extinction of the Dinosaurs
This may truly have been Alvarez’s biggest achievement and one that set off a chain reaction of discoveries. Alvarez's son, Walter, is a geologist. In the 1970’s Walter showed his father a slice of clay, a centimeter thick, in he middle of a tall wall of limestone in Italy. The clay was known as the KT boundary, marking the end of the Cretaceous period. The limestone below this line of clay is full of fossils, but the limestone above it is scarce. Geologists knew that whatever happened to put that layer of clay there, also caused a mass extinction and wiped out nearly half the species on earth, including the dinosaurs. What they didn’t know was why.

At this point, the paper notes that there were many, many wrong turns, dead ends, and unsuccessful attempts at solving this mystery. You’d expect as much for such a huge puzzle.

Alvarez knew that during Earth’s formation, heavy particles like iron, platinum, and iridium (to name a few) sunk through the molten layers of the newly forming planet and came to rest in its core. Thus there is very little of any of these elements in the Earth’s crust. But rocks in space haven’t gone through this process of separation, and carry with them a mixture of elements including these heavy metals. Meteorites burning up in our atmosphere leave a light but constant sprinkling of these heavy elements on the surface of the Earth. An increased level of one of these elements would imply that a larger than usual amount of rock from space had come to rest on the Earth’s surface. Alvarez focused on iridium. The amount of iridium in the soil is less than parts per billion, which means it is only detectable using techniques of nuclear chemistry. This would explain why geologists didn't noticed what Alvarez and his son found.

The levels of iridium in the KT boundary clay were through the roof compared to the rock around it. In a very short period of time, a large amount of an element known to be present in meteorites was deposited on the Earth’s surface and a significant amount of clay was deposited before limestone could form. Most importantly, these deposits coincided with a mass extinction. The father and son raced to get samples from other parts of the world. If their theory was correct, the deposits should be everywhere on Earth, since the proposed impact would have to have spread around the world to do the kind of damage they were suggesting. And indeed, over a hundred sites showed the same results. Further analysis of the clay showed that other materials were present that supported the meteorite theory including soot (suggesting much of the vegetation burned) and microscopic diamonds (created from intense heat and pressure), among others.

The work done by Alvarez and his son of course led to further investigation into the theory that the mass extinction was caused by a meteorite impact, and after Alvarez’s death scientists found what they think is the crater left over from the impact.

For a more in-depth portrait of Luis Alvarez's discoveries, see the paper by Charles G. Wohl, cited below.

Adventures in physics never fail to amaze me. Answers literally falling from the sky! Physicists like Luis Alvarez are truly geniuses for their combined discipline, ingenuity, and creativity, using the fantastic tools given to us by the natural world.

1. Wohl, Charles G. “Scientist as detective: Luis Alvarez and the pyramid burial chambers, the JFK assassination, and the end of the dinosaurs.” American Journal of Physics. 75 (11), November 2007.


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Wednesday, November 21, 2007

That Sweet, Sweet Voltage: The Electric Addiction

Futurama has a fantastic episode titled “Hell is Other Robots,” in which the show’s main robot, Bender, turns to the seedier side of robot life and develops a heroin-like addiction to electricity. Bender has to get his fix from an outlet or battery; otherwise he gets shaky, nervous, and irritable. The episode pitches the idea that if robots were like humans, electricity would take the place of hard drugs. But an article in the Daily India suggests that electricity might be the vice of robots and humans alike.

In the Indian district of Uttar Pradesh' Lalitpur, a village priest needs to have a small electrical stimulus before he can fall asleep each night. The priest gets his electricity from home appliances or live wires plugged into the wall. He sometimes leaves the wires in his mouth, under his arms, or behind his ears for the entire night. The article doesn’t say exactly how strong the stimuli is, or if the priest prefers a short jolt to a long tingle, but doctors in the village believe he’s built up a tolerance to it after using it for four years.

The article seemed like a fluke, until I read that the priest used to be addicted to drugs like opium and marijuana. While some villagers think the priest is divine for his ability to handle the impulses, he believes they’re what have kept him clean. Instead of doping up on traditional drugs, he satisfies his cravings with the electrical stimulus.

It turns out that electrical stimulus has been used as a treatment for alcohol addiction for a few years now. Cranial Electrical Stimulation (CES) units have drastically improved the success rates of some alcoholism treatment centers in the US. The patients attach the ends of the device to their earlobes and receive a small current “similar to the electrical pulses in the body.” Patients who were constantly re-entering rehabilitation have found long-term success with the devices, and one treatment adviser thinks it’s the miracle they’ve been looking for. Somehow, the electrical stimulus has satisfied or taken the place of the chemical stimulus they used to seek in alcohol and other drugs.

I was thinking about electrical stimulus on the brain, when I recalled that not all electrical treatments are similar to the ‘mild pulses of the body’. Electroshock therapy (EST) uses enough electricity to cause nerve damage in a few seconds, and can kill a person in a few minutes. It was discovered in the 1930’s and is used to treat severe cases of manic-depression and schizophrenia. In the film A Beautiful Mind, mathematician John Nash undergoes EST, only to be left slightly handicapped and still suffering from schizophrenia. In fact it has been said that considering its damaging side effects, the treatment may have been used too frequently in its early days, when doctors understood it even less. But use of the treatment continued because in some cases, EST yielded amazingly positive results. Cases of manic depression and schizophrenia practically disappeared in patients who showed no response to drug treatment. Somehow, the electrical stimulus drastically altered a malfunctioning process of the brain.

Today, EST is used less frequently, and only on patients with severe symptoms who don’t respond to drug treatment. And sometimes it shows remarkable, positive results; saving people from otherwise untreatable mental illness. What makes these results all the more incredible is that neurologists still don’t really know what happens to the brain during EST. Questions remain such as why the treatment works for some people and not for others; why it can cure manic-depression and schizophrenia, but not other ailments; and especially why it can have such dramatically different effects than chemical treatment. And in the cases presented here, we have to wonder why it is that electrical stimuli can do the equivalent of chemical stimuli for the Indian priest, and then do what chemicals can’t do for those cured by EST. But it works for some people, and that’s enough reason to move forward with both treatment and investigation. The Indian priest’s self medication is an example of neuroscience having data but no solid theory.

The idea of an "electricity addiction" might sound funny, but when I Googled the phrase, I got a lot more hits than I expected. I soon realized that most of them were referring to the fact that even though we don’t all stick our tongues in the toaster every the morning, America’s energy usage suggests that we’re all fairly hooked on that sweet, sweet voltage.


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Tuesday, November 20, 2007

Fire from Salt Water: Lets Focus, People.

A man in Erie can make salt water burn!

In a manner of speaking, yes. He’s freeing the hydrogen and it makes a flame but really it's just re-bonding with oxygen so it...


You
can run an engine with it!

Well, yes, it's fire, which can do that, but you have to run the radio wave generator and...


We have tons of salt water! We can use this instead of coal and oil!
No.

No no no no no no.

No.

Stop. No. Ow. Can I get an aspirin?

“New Source of Energy in Salt Water” sounds so good you just want to believe it. Bless your little heart for having so much faith in these times of despair and no snow, but unfortunately a gallon of free gas isn’t worth anything if you use up two gallons getting to the station.

Always ask questions. It’s where answers come from. Questions like, if radio waves + salt water = fire, why don't the oceans ignite from radar? Or, if our bodies are 70% water and some salt, why doesn't the radio wave generator cause internal bleeding in the guy running it? Here are the most common questions I’ve seen on blog discussions on this topic:


So…can salt water burn or not?

The video isn’t a fake; he’s actually started a fire. But do you think water can burn? Really, does that make sense? Usually water puts fires out. Knowing that, you might suspect that something isn't being fully explained here. And in fact, this is where most news stories on this are getting things backward: water doesn't burn. Water is produced when hydrogen "burns".

It's really no mystery what's going on in the video. The hydrogen can’t burn if it’s bound to oxygen (like it is in water). But, if you mix the water with sodium chloride you loosen those bonds. Then, if you do something like hit it with a very strong radio wave, then you separate the hydrogen and oxygen. Now add heat and the hydrogen will make a flame. This is the flame you see in the video. The experimenter has separated the oxygen and hydrogen and is burning the hydrogen, not the water.

But wait. Remember what I said about questions! What does it mean to burn hydrogen? Where does the oxygen go? Here's where the confusion arises: hydrogen burning = bonding with oxygen to form water. The hydrogen, in order to "burn" must re-bond with the oxygen you just separated it from. You're just ending up with exactly what you started with but spending energy to get it.

All that the radio man has done is spent energy breaking apart the water bond, given heat to the hydrogen/oxygen mixture, and released a little bit of energy putting them back together. The bottom line is all you are doing is taking apart the water molecules, and by making a flame you put them back together but that does not release any more energy than you've already spent. This is not a matter of how efficient the radio wave generator is. This is not a matter of how much salt is in the water. This is simply a matter of understanding what chemical reaction is actually taking place.


What if we get a more efficient radio wave generator?
The inefficiency of this system has nothing to do with the radio wave generator, although it is a bit like pulling apart a piñata with a team of horses (excessive). This has to do with the simple fact that it is impossible to break the bonds between hydrogen and oxygen in water and put them back together (=burn the hydrogen) without losing energy.


But it's still revolutionary that he's managed to make flame by splitting water molecules...right?

I sense you're starting to doubt CNN.

We already know how to separate water molecules into hydrogen and oxygen. You can do it at home with a battery. There are lots of very easy ways to do it. This might be the first time someone has done it with a radio wave. But really, there was no need. Check out this website on how you can do it at home:

http://www.theodoregray.com/PeriodicTable/Stories/001.1/index.html


Fire is energy. We need energy. Can we use this as an energy source?

No.

A guy in a lab shoots a radio wave (using energy) at a beaker of salt water and fire starts atop it (creating energy). Unfortunately, the radio wave (or whatever method you use to break the bonds) consumes more energy than the fire releases. You spend two gallons of gas getting one for free. Therefore, it can’t be used as an energy source, because you haven’t actually found a source of energy. You’ve found a terrible exchange rate.

It costs energy to split the hydrogen and oxygen. Putting them back together does release energy but not as much as you spent breaking them apart. That is just a fact of nature.


If you can’t create energy or destroy it, how can a reaction end up with more or less energy than it started with?
The salt-water-on-fire reaction is a negative energy equation. Negative because you lose some energy to the system around you, or for processes that don’t pay off in the energy release, or just because you took three lefts to make a right. Breaking those bonds might cost more energy than they give back, depending on how you break them. Even if the reaction were perfect, though, you could only get as much energy out as you put in because you're simply reversing the action.

There are such things as positive energy equations. These exist when energy has been stored in something prior to the start of the reaction, and often involve a catalyst (something to lower the energy needed to make the reaction happen). The best example: gasoline.

Lighting gasoline on fire gives off more energy than the person who ignited it put in. The energy comes from the breaking of chemical bonds. They key is that nature put those bonds together, not us. We’re taking advantage of someone else’s work. It’s what we do when we eat food: the plant got energy from the sun, stored it in a little energy piñata, and we came along, broke it open and took all the candy. So to speak. The earth and millions of years under pressure put energy into oil and coal. The sun could heat things for us. The wind could move things for us. There are ways to get energy out without putting it in, but breaking apart salt water and putting it back together is not one of them.


Is getting energy from water hopeless?

Hard to say. Keep your eye on scientists studying electrolysis, or ways of getting hydrogen out of water with electricity, for new innovations. But the trouble is finding innovative ways to get more energy out, not finding new ways to separate hydrogen and oxygen.

Buzz Skyline pointed out to me that we should look to nature when questioning this phenomenon. Nature is far more resourceful than we are. If there were a way to get energy out of salt water, without spending more energy than you get, there would probably be creatures utilizing it already.


We use energy to turn oil into gasoline, to process it and ship it. It’s getting very expensive and cars aren’t 100% efficient when they burn it; isn’t that putting in more energy than it’s getting out?
Possibly. This is partly why oil prices fluctuate so much. Some people might argue that we put more energy (and money) into getting oil than we can actually use it for, especially with the environmental costs. For that reason, people might think that we should at least investigate this salt water thing to see if it turns up something useful and less harmful. But remember that burning hydrogen is really what you’d be talking about. For that, there is no reason to use the radio waves or to break apart water; we have un-bonded hydrogen in the air.

And remember that neither hydrogen in the air nor in seawater is a renewable resource. We could still run into ecological problems if we tried to use either of those.

Plus, if we just offer ourselves another energy source that doesn’t make us change anything, doesn't make us more aware of our energy spending, and which potentially hurts our ecosystem in another way, then what good have we done? Ideally, hydrogen cars would replace gas cars without disrupting the driving schedule of most Americans. But what does that teach us about solving the problems we create? Even hybrid cars give a false pat on the back to consumers because we think a handful is making a difference. We need to stop looking for a magical solution to the energy crisis and admit that there are solutions available, but accepting them would just mean being aware of the problem we've created.


You’re being awfully nice about this whole thing. Doesn’t it make you just a little bit ANGRY that the news is manipulating this story to make people think we’ve found a new energy source, and that people aren’t taking the time to question why this hasn’t been used already, or why a retired radio technician is being treated like a revolutionary physicist?

Good question.


And remember kids, the inventor of fire breathing salt water says:

“This is the most abundant element on Earth. Water. Salt water.”

I’ll just let the chem geeks stew on that one.


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Friday, November 16, 2007

Stonehenge: Just add physics

Wally Wallington can move 2-ton cement blocks or barns over large distances by himself. No heavy machinery. No help. Just physics! He thinks he may have figured out how Stonehenge was built, and that it could have been done with very few people. This video shows not only some very basic physics principles in action, but illustrates that physics needs creativity and ingenuity to be put to work.

This video is about 6 minutes long, but it’s worth a look. Full of lots of physics and really awesome feats!

Read on to learn a little more about why Wally can move a barn with a 2x4. Getting it up on the pivot is something you’ll have to figure out from the video. The physics involved: center of mass and inertia; an object in motion tends to stay in motion; basic lever. This might be old hat if you’ve had basic physics classes, but I had to check my book to make sure I got the mechanics right.

Balancing a Barn- Put a pivot under and object's center of gravity, and the object will balance. No matter how big or oddly shaped the object is, that little point means equilibrium and that means it will sit tight. If you threw a tractor in the back left corner, gravity would pull more on that side, and the center of gravity would change. In terms of the barn, that point is relatively close to the center.

Rotating it- Wally uses a lever to push the barn around. Try opening a door by pushing on a spot right next to the hinges. It takes way more effort than to push it out by the handle, but you move your hand further using the handle. If you tried to rotate the barn by pushing directly on it, it’d be much harder than pushing a long 2 by 4 extending off the side of the barn. It works like a crowbar; you can move lots of mass but you have to move yourself a greater distance. Wally has to go all the way around the barn just to move it a few inches. So crowbars, see-saws, and barn movers still move a lot of mass, but they have to move over a larger distance to do it.

Getting it going - Once the barn is balanced on the pivot, gravity only plays a part in the frictional forces between the pivot and the ground. The motion of the barn in the horizontal direction is in the hands of its rotational inertia. Heavier objects are harder to push because of their mass, not their weight: Mass=stuff it’s made of; weight=stuff it’s made of + gravity; gravity only pushes down

The inertia is Newton’s second law. The barn doesn’t want to move while it’s at rest, but once it gets going it doesn’t want to stop! You have to overcome the initial energy needed to get it going, but then as you can see in the video, the barn moves much easier. Frictional forces eventually slow it down again

Moving the Barn Forward -Think of the center of mass as being in the center of a cement block. Now picture two pivot points on either side of the center of mass. If you put a mass on one side of the block you can change the center of mass to one of those pivot points. You can change the point where the block will balance. If you rotated that mass 180 degrees on one of those side pivots, the longer end would be pointing in the other direction. The block has moved in that direction. Change the center of mass to the other side of the block, and the long end is now the short end. Swing it around and the block has moved again.

Ok, think about it like walking with your knees and hips locked in place so your legs are totally straight. You step on one foot and pivot forward, step on another foot and pivot forward. Kind a like that.

In addition, Wally’s lever has its load on the pivot. This anchors the pivot and maximizes the work the lever can do.

Side Note on COM:

Center of mass is easy to imagine in an evenly weighted square block: it’s in the center. But if you really want to see how center of gravity works take a piece of paper cut like a pear or a kidney, and try to pin it to a wall. Keep the paper so it’s not touching the wall, or friction will play a part. Try pivoting it on the pin and it will usually slip back to a place of equilibrium where the heavier end is pulled down. But pin that piece of paper at its center of gravity, and you can pivot it all you want, and it will never slip down. The larger end can point up, down, or sideways. That’s equilibrium! It’s being pulled on equally from all sides.

Check out Wally Wallington's Website:

http://www.theforgottentechnology.com/



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Thursday, November 15, 2007

The Musical Tesla Coils

Will Tesla Coils make their way to Best Buy shelves this year? It's unlikely that they'll trump an iPod on sound quality, but you can’t beat the visuals.

That singing highway was awesome (see the Nov. 13 entry), but I think it’s strongly challenged by today’s feature: The Musical Tesla Coils. Manipulation of Tesla coils to make noise has been done before, but this takes the cake. What you’re hearing is the theme from Super Mario Brothers, created by an output of plasma pushing on the air as it's frequency is changed.

Also check out "The Dance of the Sugar Plum Fairy" and others:
http://www.youtube.com/watch?v=Opf5jIukSBM&feature=related

Sound waves are vibrations of the air around us, which you can make just by clapping your hands or talking. Pitch is just the number of times the air vibrates per second. Higher frequency, higher pitch. Tesla coils are a combination of circuits that output thousands to millions of volts. That high electric field arcs up and out of the coil, filling the air with sparks and making it possible to light up fluorescent lights wirelessly. Certain types of Tesla coils, like the one used here, are putting out hundreds of sparks per second, with a rest between each spark. That's already a lot like a sound wave. Each spark is pushing on the air and can create a sound. Change the frequency of the sparks and you get an equal frequency wave, hitting your ears like a note of music. The creators had to find a way to move seamlessly between frequencies to make the notes sound distinct, instead of just playing the whole scale.

The creators and musicians Jeff Larson and Steve Ward have a website explaining how to make your own musical tesla coil, if you have the means.
http://www.stevehv.4hv.org/MusicalSSTCs.htm

Another example of the creativity that comes with such heavy machinery: the Tesladownunders Car Theft Protection (this is not an altered photo).

From http://tesladownunder.com/tesla_coil_sparks.htm.


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The Latest from the Extreme Sports Physicist

Ever wonder what makes snow so slippery?

Or what physics can say about the highest aerial ever recorded on a snowboard?

Where do moguls come from anyway?

And, what are the chances that someone could snowboard to safety in an avalanche?

Check out the latest posts on the Extreme Sports Physics blog to get the answers to some of the physics questions nagging at those of us in the Northern hemisphere as we get ready to hit the slopes and the ice this winter.
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Tuesday, November 13, 2007

A Singing Highway

There used to be a stretch of road near my house that was haunted - at least that's what I would tell my passengers as I drove along it. As we approached a certain intersection, a creepy moan would fill the passenger compartment. It scared the daylights out of a few people, especially when I took them for rides at night while telling tales about ghostly hitchikers.

The bit about ghosts, of course, was made up, but the moaning road was real. The road had become rippled with age, which made the tires play a haunting tone. It worked the same way that a record needle (remember LPs) plays sounds as it rides over the bumps in the recording tracks.

I often wondered why nobody ever bothered to take advantage of the effect by making roads that played sounds on purpose (perhaps as a type of advertising, or to alert drivers to speed limits and such).

Well, someone HAS done it in Japan. They have a whole stretch of singing highway, clearly marked with musical notations to let you know you haven't lost your mind. Play the YouTube video below to find out what the singing road sounds like. I don't read Japanese, but the subtitles suggest that the the road is playing a well-known Japanese song.


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Thursday, November 08, 2007

Einstein's Hype


"In teaching history," he replied, "there should be extensive discussion of personalities who benefited mankind through independence of character and judgment."
-Albert Einstein, from the New York Times Book Review Online

There seems to be no end to the fame Albert Einstein achieved during his life and beyond. Not only are there already more books written about the guy than, I would bet, any other scientist ever, but the newest one (pictured here) made it to the top of the NY Times bestseller list! People still want to know more about the guy who's credited with revolutionizing an already difficult field of study, making it exciting for a general audience, and flashing the personality of a poet. Everyone in the western world knows what it means to be called an Einstein. With this much worship being spilled on the guy, I have to wonder if physicists studying his work today think Einstein deserves the praise he gets. Are his discoveries turning out to be as amazing as they seemed at the time of their release?

I had the chance to speak with David Garfinkle, who got his PhD from Chicago University and now teaches and does research at Oakland University in Michigan. He’s also the Chair Elect of the APS Topical Group in Gravitation, as well as the editor of their newsletter. David specializes in gravitational collapse and singularities. He and his brother have written a book about gravitation that will be coming out in the next year. I was pretty sure if anyone could answer my question, David could. I put it to him simply: Does Einstein deserves all the hype?

The simple answer was yes. Definitely, enthusiastically, yes. Over the years Einstein’s work has stood the test of time and new developments. It forms the firm basis of what we now know as the study of gravity. While new theories of gravity are published from time to time, they’re proven faulty compared to general relativity. Einstein remains an Einstein, even in the eyes of his followers.

David pointed out that in the field of quantum mechanics Einstein was important, but so were many other physicists. There were multiple contributors, a handful of whom did equal or more work than Einstein including Bohr, Heisenberg, and Schroedinger. But so far as general relativity goes, Einstein seems to deserve the momentous praise he has gained.


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Tuesday, November 06, 2007

TV and Physics don't quite get along

CBS just launched The Big Bang Theory, a new sitcom about two physics guys with no social skills and a hot “blond” girl with a cell phone. Putting aside reviews, TBBT makes me question whether or not TV has given scientists a bad rap.

There tend to be three prominent stereotypes that follow physicists wherever they go, and TBBT embraces all of them (I will note that these apply far more to male physicists): physicists are socially inept (except with other physicists), they like people of the opposite sex but turn into goop around them, and they constantly speak in overly complicated jargon.


But wait! Since George Clooney’s reign on ER it’s clear that not all TV scientists are created equal. Doctors have not only beat the rap of nerds, but are triumphantly portrayed as abnormally attractive.





And this isn't an isolated incident. Multiple shows have run off with the hot doctor idea despite the fact that there are physics concepts around every defibrillator!




On the X-Files, Gillian Anderson’s character got her B.S. in physics, but then went to medical school, putting her somewhere in the middle of the spectrum. Still, Scully was dubbed the “scientist” of the duo. She had ONE date in NINE YEARS.






Gilligan's Island definitely added to the idea that we should just accept the jargon that scientists throw at us and never question a radio built out of coconuts. The Professor was was kind of rugged and calm, not up-tight and glued to an inhaler like other nerds. Yet the non-sexuality played in at a new level because he seemed kind of gay.




Jerry Lewis pretty much defiled chemists for all time with the Nutty Professor.








While I hate to see my beloved physicists turned into nothing but a stereotype, sometimes I wonder if we haven’t got it coming.



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Thursday, November 01, 2007

Fun with Fluids

This is so cool! What’s really neat about this demonstration is that there’s some fairly simple physics going on. Watch as a jet of oil falls into a rotating bath of the same oil, only to arc up and out. Believe it or not, it’s just a thin layer of air keeping the jet from losing its shape and combining with the bath. The elastic or trampoline-like properties of the bath bounce the air-cushioned jet back up above the surface, while the rotation of the bath keeps it from bouncing into itself. This was discovered by accident, which might make you wonder how much spare time physicists really have on their hands.




The jet maintains its shape because of a thin layer of air caught between the fluid of the jet and the bath. It’s pretty common; you can see it in raindrops hitting a pond. The air is extremely sensitive to disruption so if you’re trying to do this at home you’ll need a very steady hand and some patience.

When the jet falls down and pushes on the bath, the bath will push back (that’s Newton’s 3rd Law!). But the fluid is elastic, so it bends under the force of the jet (allowing the jet to dip under the surface). The elastic bath rebounds back and pushes the jet up and out. So the bath acts like a trampoline. In some videos of this, the stream makes two arches as it bounces off the bath a second time.

If you’re doing this at home, don’t forget the importance of rotating the bath! At very low velocity the stream bounces almost vertically back up. But these low velocities tend to have fewer successful arcs. Go to a higher velocity than is shown in the video, and the arcs get more and more horizontal, until they ride across the surface of the pool. If you’re careful, you can also do this by moving the jet and leaving the bath still.

Scientists are investigating ways to control these air layers. The cushion of air can also make a liquid coil up like a rope, float on the surface, or form into droplets. They’re also investigating ways to control the air cushions through various methods including vibration, evaporation, or (similar to this experiment) varying the velocity between the jet and the bath.

More fun with fluids from Physics Buzz! à http://physicsbuzz.physicscentral.com/2006/10/waveparticle-duality-living-large.html

The paper reporting this experiment is really interesting to read, and it’s not too heavy. A summary and tons of links, including the original paper, can be found here: http://chaos.ph.utexas.edu/research/fluids/bouncing_jet.html




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