All posts by Chad

The Exotic Physics of an Ordinary Morning: Talk at TEDxAlbany

I gave a talk at TEDxAlbany on December 3, 2015, on “The Exotic Physics of an Ordinary Morning”:

You might think that the bizarre predictions of quantum mechanics and relativity– particles that are also waves, cats that are both alive and dead, clocks that run at different rates depending on how you’re moving– and only come into play in physics laboratories or near black holes. In fact, though, even the strangest features of modern physics are essential for everything around us. The mundane process of getting up and getting ready for work relies on surprisingly exotic physics; understanding how this plays out adds an element of wonder to even the most ordinary morning.

(This is based on a preliminary draft; final talk does not, in fact, discuss relativity.)

Talk slides are here slides on SlideShare:

More details in this blog post.

Failure in Real Science Is Good– And Different from Phony Controversies

Failure in real science is good – and different from phony controversies

By Chad Orzel, Union College

Last March, the BICEP2 collaboration announced that they had used a microwave telescope at the South Pole to detect primordial gravitational waves. These tiny ripples in spacetime would be the first proof of the theory known as “inflation,” an astonishingly rapid expansion of the universe in the instants after the Big Bang.

The result was announced in a paper, a press conference, and a viral video of BICEP2 member Chao-Lin Kuo visiting cosmologist Andrei Linde, one of the inventors of inflation, at his home with a bottle of champagne to celebrate.

Last week, a new paper was released backtracking on last March’s announcement. The BICEP2 team joined with rivals on the European Space Agency’s Planck experiment, and found that their results were contaminated by dust. The signal is not large enough to constitute proof of inflation, so cosmology returns to its prior uncertain state. Rather than revolutionizing our understanding, the BICEP2 result is just the latest in a long line of highly public flops.

Oh, those gravitational waves we detected…? Yeah, that could have just been dust.
BICEP2 Collaboration, CC BY-NC-ND

Did the hype hurt or help science?

Along with general disappointment, the new announcement has prompted discussion of what, if anything, the BICEP2 team did wrong. Many commentators fault them for over-hyping their results to the mass media before peer review. Some even argue that this has dire consequences – astronomer Marcelo Gleiser says the announcement and revision “harms science because it’s an attack on its integrity,” giving “ammunition” to those who raise doubts about politically charged areas of science.

Looked at another way, though, the BICEP2 story may in fact be ammunition for supporters of science. BICEP2 shows how science is properly done, and makes it easier, not harder, to detect the pseudo-science of attempts to discredit science for political gain.

We tend to think of science as a collection of esoteric information, but science is best understood as a process for figuring out the workings of the universe. Scientists look at the world, think of models to explain their observations, test those models with further observations and experiment, and tell each other the results. This process is familiar and universal, turning up in everything from hidden-object books to sports. More importantly, we can recognize the process even in cases where we don’t understand all the technical details, and use that to distinguish real science from phony controversies.

Refining real science versus phony controversies

Real scientific controversies are widespread and mainstream. The BICEP2 results were publicly challenged within weeks, by other scientists working in the field, who quickly identified dust as a trouble spot. While few of the participants were disinterested—most complaints came from scientists associated with BICEP2’s competitors and theorists who prefer alternatives to inflation—they were active and respected members of the community.

Celebrity advocates amplify the controversy around issues like vaccines, though the science itself is not controversial.
Yuri Gripas

Phony controversies, on the other hand, can usually be traced to a handful of opponents, often outside their fields of expertise. Challenges to the scientific consensus on climate change mostly come from engineers and economists, not working climate scientists, and tend to originate in think tanks and lobbying groups, not university research labs. Fears about vaccines can be traced to a handful of thoroughly debunked studies, and are stoked by politicians and celebrities, not medical researchers.

Real scientific controversies play out in the scientific literature, through papers drawing on many other sources of data. Within months of the original announcement, a detailed re-analysis of the data was posted to the physics arxiv (the online repository physicists and astronomers use to share their results), using multiple alternative models to show how dust could explain the results. Others drew on previous measurements to show that BICEP2’s claims were difficult to reconcile with existing data.

Phony controversies tend to play out in the media, through press releases, stump speeches, and polemical writing reshared via social media. Reliable reports from scientific journals are difficult to find, even after chasing back long chains of references.

And most importantly, real scientific controversies are self-correcting. The final nail in the gravitational-wave coffin was a joint paper by both BICEP2 and Planck, combining their data to settle the question. The end result is professionally embarrassing for scientists involved in the original announcement, but they were at the forefront of the effort to resolve the controversy because for real science reputation is less important than the truth.

The media can perpetuate phony controversies.
cactusbones, CC BY-NC-SA

Phony controversies, on the other hand, are endless, with proponents clinging stubbornly to the same positions year after year. Even as their sources are discredited, their conclusions remain unchanged, because phony science is less interested in truth than in selling a conclusion.

Rather than weakening the standing of science, then, the BICEP2 saga should serve to enhance it. While few of us can follow all the technical details on which the controversy turns, everyone should be able to follow the broad outlines of the process. By providing a clear example of real science done the right way, the controversy over BICEP2 exposes politically motivated phony controversies as hollow frauds.

The Conversation

This article was originally published on The Conversation.
Read the original article.

Super Bowl Athletes Are Scientists at Work

Super Bowl athletes are scientists at work

By Chad Orzel, Union College

Seattle Seahawks cornerback Richard Sherman gets called a lot of things. He calls himself the greatest cornerback in the NFL (and Seattle fans tend to agree). Sportswriters and some other players call him a loudmouth and a showboater. Fans of other teams call him a lot of things that shouldn’t see print (even on the internet). One thing you’re not likely to hear anyone on ESPN call Sherman, though, is “scientist.”

And yet, an elite professional athlete like Richard Sherman is, in fact, extremely adept at doing science. Not the white-lab-coat, equations-on-a-blackboard sort of science, but the far older and universal process of observing, making and testing models of the universe.

Science is best understood not as a collection of esoteric knowledge, but a four-step process for figuring out how the universe operates. You look at the world around you, you think about why it might work the way it does, you test that theory with experiments and further observations, then you tell everyone the results. In that sense, there are few activities more ruthlessly scientific than a professional football game.

A cornerback like Sherman is given the assignment of preventing passes to a particular area of the field, but he has to decide the best approach to do that. He does this by making and updating a mental model of the other team — what formation they’re in, what they’ve done in the past — and using it to decide what he should do — which of two players to follow closely, whether to get in position for a tackle or try to intercept a pass. This model is immediately put to the test on the field, and everybody watching sees the results. Then the players line back up and do it again.

This essentially scientific process of making and testing mental models is repeated by every player on the field every play of the game — Tom Brady and the Patriots’ receiving corps will be trying to figure out what Sherman is going to do, and act accordingly. This Sunday’s Super Bowl is one of the largest scientific endeavors you’ll ever see on live television.

If this is your only image of a scientist, it’s time to update your mental models.
Lab image via www.shutterstock.com.

We tend not to think of sporting events as scientific for a whole host of reasons, from the speed of the game, which doesn’t seem to allow time for conscious thought, to politics of race and class. As Patricia Fara notes in her Science: A Four Thousand Year History, the arbitrary division between abstract science and practical technology dates back to the time of Archimedes, and even earlier. But a closer examination shows that even something like football, while commonly perceived as brutishly physical, involves an enormous mental component that parallels the process of scientific discovery.

While the look-think-test-tell process is followed in every area of science, the frequent repetition of a football game — a typical NFL game runs to better than 120 plays — finds a great analogue in the science of timekeeping. Measuring time, like playing football, involves constant testing and updating, comparing a model clock to an external standard over and over, and adjusting to keep them synchronized. The end result can be fantastically precise.

NIST-F1 Cesium fountain atomic clock, serving as the US time and frequency standard, with an uncertainty of 5.10-16.
NIST

The modern standard of time is based on quantum physics — the second is defined as 9,192,631,770 oscillations of a particular frequency of light absorbed by cesium atoms. State-of-the-art atomic clocks start with cesium atoms cooled to a few millionths of a degree above absolute zero, and toss them upward through a microwave cavity. In the cavity, they are illuminated by light from the microwave source that serves as the clock synchronizing their internal state with the lab clock. They fly up above the cavity for a time, then fall back through, interacting with the light a second time. If the frequency of the lab clock matches the atoms’ natural frequency perfectly, all of the atoms will be in a different state when they return to where they began. If the frequency is slightly off, some of the atoms will remain in their original state, and the operators know to adjust the clock frequency.

This process of testing and refinement is repeated about once a second during clock operation, and produces a time signal that would need hundreds of millions of years to gain or lose a single second. That kind of precision is a little excessive for a football game (though some Super Bowls do last a long time), but atomic clocks are essential for the Global Positioning System (GPS), a network of 32 atomic clocks in satellites. Each satellite broadcasts the time, and the delay between signals from different satellites allows the GPS receiver in your car or phone to determine your distance from the satellites. This determines your location on the surface of the Earth to within a couple of meters, about the length of an average NFL play.

Continued improvements in timekeeping technology could improve that resolution, maybe even to a level that could eliminate those annoying arguments about whether the football really crossed the goal line or not.

May the best scientists win.
Carlo Allegri / Reuters

The exceptional precision of atomic clocks has transformed everyday navigation through GPS. And it works using the same rapid test-and-refinement process that Sunday’s players will, as they constantly assess what’s going on around them on the field and adjust their actions accordingly.

So if you watch the Super Bowl this weekend, appreciate it as not just a display of amazing physical skill, but of science. Richard Sherman, Tom Brady and all the other players succeed not just through their athletic gifts, but by making and testing mental models of their opponents. In the end, the game will go not just to the strongest and the swiftest, but to the very best scientists.

The Conversation

This article was originally published on The Conversation.
Read the original article.

Football Physics and the Science of Deflategate

Football physics and the science of Deflategate

By Chad Orzel, Union College

News reports say that 11 of the 12 game balls used by the New England Patriots in their AFC championship game against the Indianapolis Colts were deflated, showing about 2 pounds per square inch (psi) less pressure than the 13 psi required by the rules, so it seems that the most bizarre sports scandal of recent memory is real. But there are still plenty of questions: why would a team deflate footballs? Could there be another explanation? And most importantly, what does physics tell us about all this?

For New England fans, the first priority is a search for an innocent explanation. After all, party balloons and car tires deflate during cold winter weather, so might a simple temperature difference be responsible for the change in inflation pressure?

The physics principle known as the ideal gas law tells us that a reduction in temperature leads to a reduction in pressure. The pressure of a confined gas multiplied by its volume is proportional to the number of molecules in the gas multiplied by the temperature. Maybe you remember the equation PV=nRT from your schooldays. So if you cool a gas while keeping its volume fixed, the pressure must decrease.

Footballs on ice… what will happen to the pressure?
Chad Orzel, CC BY-SA

But we don’t need equations to check this: we can demonstrate it directly. I got a couple of old footballs from Union College’s athletic department, pumped them up and popped them in the freezer. After a night in the cold, the pressure was around 2psi lower, just like the Patriots’ footballs — from about 19psi at the start (I slightly overinflated the balls by using the tire pump in my car) down to about 17 psi.

Of course, the temperature difference involved was a little extreme — from about 68F in my office, down to about -10F in the freezer. So, you can use temperature changes to produce the pressure change seen by investigators, but the temperature required would’ve matched the legendary Ice Bowl of 1967. Last Sunday’s game was played in pouring rain at about 50F, so unless they did the pre-game testing of the balls in a sauna, or the post-game investigation in a meat locker, thermodynamics alone can’t get the Patriots off the hook.

Pressure dropped after a night in the deep freeze.
Chad Orzel, CC BY-SA

Assuming that the balls really were deliberately deflated, then what would be the reasoning? Would the lower pressure make the ball lighter and more aerodynamic, allowing longer, more accurate passing?

This is another question easily answered with the ideal gas law — the volume of a football doesn’t change very much with pressure, so deflating it by 2psi requires reducing the amount of gas inside by about 15%. But air is, by definition, very light. The air in a fully inflated football accounts for only about 10 grams of its mass (about 2.5% of the total) and deflating it would reduce that by maybe a gram or two. (This also explains why the officials didn’t notice anything funny during the game — the change in weight from the missing air is too small to notice, particularly in bad weather, where rain probably added more to the mass of the ball than the deflation took away.)

And again, we have experimental confirmation of this — a 2006 episode of the TV show Mythbusters replaced the air inside a football with helium to see if that would allow a kicker to boot the ball father. The mass reduction of swapping helium for air is far greater than that for a 2psi reduction in pressure, but the Mythbusters found no gain in performance — in fact, air-filled balls might be slightly better, as the extra mass makes them somewhat less susceptible to air resistance.

In the end, the reason for deflating a football owes more to physiology than physics. A slightly deflated ball is a bit softer, making it easier to grip the ball to throw it and reducing the bounce when it hits the hands of a receiver, making it easier to catch. We can see this even with frozen footballs — although the cold makes the leather stiffer, the balls had noticeably more give when squeezed than before they went in the freezer. In cool, rainy conditions, where the ball becomes wet and slippery, this works to the advantage of the quarterback and receivers.

Coach Bill Belichick hoists the Lamar Hunt trophy his NE Patriots won in the AFC Championship Game.
USA Today Sports / Reuters

The most puzzling aspect of the story, though, is the scoreboard. The Patriots won the game 45-7, thoroughly outplaying the Colts in every aspect of the game. The tiny advantage they may have gained from a better grip on the ball can’t explain such a lopsided outcome. If the Patriots were that much better, why risk punishment by tampering with the footballs?

That question, alas, isn’t one the ideal gas law can answer. For that, you would need to understand the psychology of Patriots coach Bill Belichick, and that is a mystery much too deep for physics.

The Conversation

This article was originally published on The Conversation.
Read the original article.

Thermodynamics of Football in the Gazette

The Schenectady Gazette ran a piece about my experiment with putting footballs in the freezer, in the wake of the “Deflategate” scandal:

Chad Orzel sees science all around him, whether he’s teaching it in a classroom, playing pickup basketball at Union College’s Memorial Fieldhouse or kicking back to watch the National Football League.

Being an associate professor of physics and chairman of the Department of Physics and Astronomy at Union explains some of the fascination.

“I do believe the scientific process is used in all the things we do,” he said Thursday. “And there few things as ruthlessly scientific as big sports.”

That’s why he is so puzzled by Deflategate — science should have said there was little to gain and a lot to lose.

More on the experiment at The Conversation and my own blog.

Thermodynamics of Football at The Conversation

I wrote a short piece on the “Deflategate” controversy for the US edition of The Conversation, and whether physics could explain the underinflated footballs used by the New England Patriots:

News reports say that 11 of the 12 game balls used by the New England Patriots in their AFC championship game against the Indianapolis Colts were deflated, showing about 2 pounds per square inch (psi) less pressure than the 13 psi required by the rules, so it seems that the most bizarre sports scandal of recent memory is real. But there are still plenty of questions: why would a team deflate footballs? Could there be another explanation? And most importantly, what does physics tell us about all this?

As part of the story, I did an experiment, putting a couple of footballs in the freezer and measuring the change in pressure. I described that in more detail on my blog.

Where’s Waldo Goes to Outer Space

There’s a long excerpt from Eureka: Discovering Your Inner Scientist posted at Medium. This is taken from Chapter 4, and discusses pattern-matching games, astronomy, and citizen science:

While such books may seem like merely an amusing diversion for children, the mental process involved in finding Waldo and his friends in Handford’s elaborate drawings is remarkably sophisticated.
There are multiple web sites and academic papers devoted to computer algorithms for locating Waldo within Handford’s drawings, using a variety of software packages, and these are impressively complex, running to hundreds of lines of code and invoking sophisticated image-processing tools. Child’s play, this is not.

The essential element of these books is pattern matching, looking for a particular arrangement of colors and shapes in the midst of a distracting field. There are numerous more “adult” variations on this game, some of them obvious, like the image-based “hidden object” puzzle games Kate sometimes plays for relaxation, or the classic video game Myst. Other classes of games may not seem directly connected, but use the same pattern-finding tricks, such as solitaire card games like Free Cell (my own go-to time-waster) or colored-blob-matching games like the massively popular Candy Crush. In all of these, the key to the game is spotting a useful pattern within a large collection of visual data. This is a task at which human brains excel, and millions of people do it for fun and relaxation.

The unmatched ability of humans to spot meaningful patterns in visual data is the basis for many scientific discoveries, in all sorts of different fields.

Probably no field has benefitted more from pattern-matching than astronomy, though, with many of the field’s most important and unusual discoveries having their origin in the spotting of an odd pattern.

(This is my favorite of the published excerpts, because I did the edit myself…)