Inside Einstein's Mind Hero

On November 25th, 1915, Einstein published his greatest work: general relativity. The theory transformed our understanding of nature’s laws and the entire history of the cosmos, reaching back to the origin of time itself. NOVA tells the inside story of Einstein’s masterpiece. The story begins with the intuitive thought experiments that set Einstein off on his quest and traces the revolution in cosmology that is still playing out in today’s labs and observatories. Discover the simple but powerful ideas at the heart of relativity, illuminating the theory—and Einstein’s brilliance—as never before. From the first spark of an idea to the discovery of the expanding universe, the Big Bang, black holes, and dark energy, NOVA uncovers the inspired insights and brilliant breakthroughs of “the perfect theory.”

Retrace the thought experiments that inspired his theory on the nature of reality.

Inside Einstein's Mind

The Origami Revolution Hero

The centuries-old tradition of folding two-dimensional paper into three-dimensional shapes is inspiring a scientific revolution. The rules of folding are at the heart of many natural phenomena, from how leaves blossom to how beetles fly. But now, engineers and designers are applying its principles to reshape the world around us—and even within us, designing new drugs, micro-robots, and future space missions. With this burgeoning field of origami-inspired-design, the question is: can the mathematics of origami be boiled down to one elegant algorithm—a fail-proof guidebook to make any object out of a flat surface, just by folding? And if so, what would that mean for the future of design? Explore the high-tech future of this age-old art as NOVA unfolds “The Origami Revolution.”

Engineers are using origami to design drugs, micro-robots, and future space missions.

The Origami Revolution

Hunting the Elements Hero

Where do nature&#x27;s building blocks, called the elements, come from? They&#x27;re the hidden ingredients of everything in our world, from the carbon in our bodies to the metals in our smartphones. To unlock their secrets, David Pogue, technology columnist and lively host of NOVA&#x27;s popular &quot;Making Stuff&quot; series, spins viewers through the world of weird, extreme chemistry: the strongest acids, the deadliest poisons, the universe&#x27;s most abundant elements, and the rarest of the rare—substances cooked up in atom smashers that flicker into existence for only fractions of a second.

A two-hour special from the producers of &quot;Making Stuff&quot;

Hunting the Elements

topic-physics-math.jpg

Physics & Math

Koch Foundation

Draper

Learn about gerrymandering—the manipulation of district boundaries for political advantage—and see how geometry can be used to detect and help solve the problem in this video from NOVA.

Can Math Help Detect Gerrymandering?

Researchers recently made a bunny almost entirely invisible to infrared. But achieving true invisibility is a much more difficult feat.
How do we see objects? By intercepting waves of light bouncing off of them and into our eyes, each reflected at a different angle. One way to achieve invisibility is to bend the paths of light using lenses, mirrors, or metamaterials with unique reflective properties. There are a lot of problems still to be solved—and valuable applications awaiting those who succeed.
Using Science to Achieve InvisibilityPublished: April 5, 2019Onscreen: It&#x27;s springtime. So why not make a bunny invisible? Researchers made this one invisible to infrared. Infrared radiation is visible through night googles. The warmer something is, the more infrared there is.Hao Bai&#x27;s team looked to polar bears whose hair traps heat. They made a synthetic material that does something similar and put it on a bunny.Hao Bai: Under an infrared camera, you can barely see the body of the bunny. It’s because… there’s no infrared emission from the bunny’s body out across the fabric.Onscreen: Instead, all the heat is trapped under the cloak. But what would it take to achieve real invisibility?Jose Azaña: The first thing that is important to understand is how you see an object.Onscreen: Waves of light travel from a source to an object. These waves bounce off that object and into your eye — each reflecting at a different angle. One way to achieve invisibility is to bend these paths of light.Azaña: Typically, the waves propagate in a straight line…but in this case, you will be doing something to the wave so that it is curved, and it goes around the object. And in this way, you avoid the interaction between the object and the wave…Onscreen: rendering it invisible.Joe Choi: We used mirrors and a four-lens system to deflect light around a body. You’d be able to see this optical effect where you see around maybe my fingers.Onscreen: Researchers are also using metamaterials to bend light.Azaña: Those are materials that offer properties in their interactions with waves that cannot be found in nature. You take different materials, you put them together in a way that’s not obvious and you can do to the waves things that the natural materials will never do.Onscreen: These metamaterials are super tiny and arranged into specific patterns.Choi: Then you can guide light around a region and that region becomes invisible.Onscreen: Another way of achieving invisibility doesn&#x27;t bend the light at all.Azaña: We do a kind of manipulation of the properties of the wave so that it can pass through the object like a ghost.Onscreen: Because the detector sees the same light that was emitted, the object seems invisible. Achieving invisibility isn&#x27;t easy.Azaña: There are a lot of problems still to be solved.Choi: For metamaterials, the main difficulty is they can only really do it for a single wavelength. For ours, the main difficulty is that we have limited range of angles that you can do it. You can’t get everything. That’s the limit of physics.Onscreen: If we manage to resolve these problems, there are larger applications: military operations that require stealth, surgeons who could see without their hands being in the way, and pilots seeing the runway below them as they land a plane.Choi: If you could scale this…maybe a…suit would be more practical… As the suit moves, you know where it’s moving in relation to the suit and you can map the light so that it goes around perfectly so that it just becomes invisible.Azaña: I want to believe that it will take us to a point where we can make it practical…to create invisibility cloaks and invisibility devices.

Researchers recently made a bunny almost entirely invisible to infrared. But achieving true invisibility is a much more difficult feat.

Using Science to Achieve Invisibility

Baseball vs. Soccer: Which sport has the best curves?
When a ball traveling through the air is spinning, some physics known as the magnus force kicks in to make it bend or curve. The magnitude of the magnus force depends on the ball’s rate of spin as well as its mass, velocity, radius, and the density of the air around it. 
How the Magnus Force Curves Soccer and BaseballsPublished: April 5, 2019Onscreen: Baseball vs. Soccer. Which sport has the best curves? Baseball with its curveballs?David Bush: I try to make it move as much as I can within the strike zone.Onscreen: Or soccer? With kicks like this one?André Akpan: When you hit it right it’s just such a perfect feeling. There’s no specific term. Curve it, bend it. If you want to get funny, some people say they put a little sauce on it.Onscreen: Science may have the answer.Dr. Idaykis Rodriguez: When the ball is in the air spinning, there’s this force which makes it bend or curve.Onscreen: It’s called the magnus force. Imagine a ball flying through the air. As it moves, it pushes the air to each side. Now, imagine the ball is spinning counter-clockwise.Dr. Rodriguez: The air that’s going with the spin is moving faster than the air that’s going against the spin.Onscreen: Friction on one side pushes against the air but pulls air along the other making it speed up and curve around the back of the ball. The action of pulling the airflow around the back of the ball is key because every action has an equal and opposite reaction.Dr. Rodriguez: That’s Newton’s third law.Onscreen: A swimmer propels herself forward by pushing the water backwards. A rocket blasts off by shooting gases out beneath it. The airstream flies off the back of the spinning ball forcing it in the opposite direction.Dr. Rodriguez: This makes the ball go to the left.Onscreen: The magnus force works on more than soccer balls and baseballs. It can make cylinders like this do crazy things. Back to the question: Who curves it better?Dr. Rodriguez: The magnitude of the magnus force depends on the spin of the ball, the velocity of the ball, the radius of the ball.Onscreen: It also depends on air density.Dr. Rodriguez: If there were no air it would just go as straight as possible into its target. The ball carries better in thinner air. If there’s a payer in Denver vs. a player in Florida, the curveball that the Denver player experiences is probably going to curve less than the player in Florida.Onscreen: The ball’s shape matters too.Dr. Rodriguez: If it’s a ball that’s kind of smooth, it doesn’t bend as much.Unknown male: The major league baseball standards are pretty tight. So, generally most balls are almost exactly the same.Akpan: Traditionally most soccer balls have had a pretty standard pattern. But in the last 10-15 years you’ve seen different patterns and styles.Onscreen: The result is that the average soccer ball has gotten smoother. Baseballs still have the same raised stitching. These factors help give you the strength of the magnus force. But calculating the ball’s curvature requires something else.Dr. Rodriguez: To directly calculate the magnitude of the force, you will need the mass of the ball.Onscreen: Here’s the final tally. Baseball is looking strong but the strength of the magnus force also depends on the radius cubed. Soccer wins the curved test.

Baseball vs. Soccer: Which sport has the best curves?

How the Magnus Force Curves Soccer and Baseballs

Learn why different experimental designs were needed to collect evidence for quantum entanglement in this media gallery of videos from NOVA Einstein’s Quantum Riddle.

Collecting Evidence for Quantum Entanglement

Conceptualize the nonintuitive idea that electrons can behave both as a wave and a particle (wave–particle duality) in this video from NOVA Einstein’s Quantum Riddle.

Wave–Particle Duality of Electrons

Conceptualize quantum entanglement, the idea that particles can instantaneously influence each other even when they are spatially separated, in this video from NOVA Einstein’s Quantum Riddle.

Quantum Entanglement

<div class="rich-text">If you’ve got a couple grapes and a microwave, it’s technically possible to make plasma in the comfort of your own home. The catch? There’s a very real possibility neither the microwave nor the grapes will survive the encounter.For those unwilling to set their kitchens ablaze, however, there’s good news. For one, it’s not terribly hard to sate your curiosity on YouTube—but more importantly, after decades of speculation, a team of researchers has finally <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.1818350116">puzzled out the physics</a> behind this mind-bending phenomenon so you don’t have to (please don’t). Your kitchen—and your landlord—will thank you.</div>
 

 
 <div class="ad"></div>
 

 
 <div class="rich-text">Here’s the deal. In most online iterations, an intrepid citizen scientist will <a href="http://movie-usa.glencoesoftware.com/video/10.1073/pnas.1818350116/video-1">slice a grape</a> in half, leaving just a thin, connective bridge of skin, and nuke the split fruit on high. After a couple seconds, the center of butchered grape will begin to belch out fiery, amorphous little sparks that ricochet through your microwave. Voilà: DIY plumes of piping hot plasma (as an aside, this is probably the point where the reaction should be shut down).<div style="padding-bottom: 56.25%;" class="responsive-object">
 <iframe width="480" height="270" src="https://www.youtube.com/embed/z5LYBSd1cj4?feature=oembed" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</div>
This <a href="https://www.livescience.com/54652-plasma.html">plasma</a>, of course, is not the plasma of blood, but the state of matter (as in solid, liquid, gas, plasma) that’s like a gas, but consists of charged, or ionized, atoms whose electrons have been stripped away from their positively charged nuclei. The result is a swarm of subatomic particles that clash and collide, often emitting roiling blobs of light and heat that can resemble molten fire.Plasma is naturally found in lightning, the Earth’s ionosphere, and the Sun’s corona, but can also be artificially generated by exposing a gas to blistering temperatures or an electromagnetic field—basically, something that can infuse the gas with enough energy to jostle electrons loose from their atoms.So what business does plasma have roaring out of nuked grapes?This question plagued physicist <a href="http://www.aaronslepkov.com/">Aaron Slepkov</a> of Trent University in Canada for two decades. Slepkov first witnessed the phenomenon while surfing a website called “Fun with Grapes” in 1995. But while videos and blog posts of microwavable plasma abounded, it seemed there were no rigorous, scientific explanations for the physics behind the frivolity. So many years later, when Slepkov started up his own research group, he and his trainees, including study author <a href="http://www.aaronslepkov.com/">Hamza Khattak</a>, decided to put some theories to the test. The scorched fruits of their labor are <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.1818350116">published today</a> in the journal PNAS.</div>
 

 
 <div class="related"></div>
 

 
 <div class="rich-text">One myth was quickly busted: a split grape wasn’t a necessary component of the blaze; in fact, the phenomenon wasn’t grape-specific at all. Sparks flew just fine with <a href="http://movie-usa.glencoesoftware.com/video/10.1073/pnas.1818350116/video-2">intact grapes</a>—as well as with gooseberries, particularly buxom blueberries, and even <a href="http://movie-usa.glencoesoftware.com/video/10.1073/pnas.1818350116/video-3">self-contained beads of salted water</a>—as long as there were two of them, and they were touching.The key, it seems, is cramming the energy present in microwaves into a very tiny space—the point of contact between the objects in question. In your garden-variety microwave oven, microwaves have a wavelength of about 12.5 cm. But adjoining grapes (which are full of water that can absorb said microwaves) can concentrate the energy within into a region where the two spheres touch, which is no more than a couple millimeters wide. This creates a very strong, very condensed electric field at their interface—a pocket of ammo powerful enough to liberate negatively-charged electrons from, say, the salts naturally present in grapes and other fruits. And the results are explosive.A single grape by itself can’t do the trick, though. In these cases, the energy simply <a href="http://movie-usa.glencoesoftware.com/video/10.1073/pnas.1818350116/video-5">concentrates at the center</a> of the grape. But if joined by a willing dance partner, the “hotspot” in each grape gravitates towards the other, until the two synergize in a blaze of glory.<div style="padding-bottom: 56.25%;" class="responsive-object">
 <iframe width="480" height="270" src="https://www.youtube.com/embed/0LmaXQsssYY?feature=oembed" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</div>
Ultimately, microwaving your way to plasma is actually a pretty flexible feat, as long as you’re mindful of size, says study author <a href="https://www.concordia.ca/artsci/physics/faculty.html?fpid=pablo-bianucci">Pablo Bianucci</a>, a physicist at Concordia University in Canada. With microwaves of this wavelength, typical grapes have a pretty ideal diameter. Scaling up to anything too much bigger than a grape—like a tomato—won’t concentrate the energy into a tight enough space (for that, you’d need to scale up the wavelength too). Conversely, undershooting the size will prevent the spheres from absorbing enough energy to begin with.“This really shows that there’s an explanation for everything,” says <a href="http://physics.case.edu/faculty/lydia-kisley/">Lydia Kisley</a>, a physicist and nanoscience expert at Case Western University who was not involved in the study. “Physics can be used and applied to everyday phenomena. All these theories that were developed with pencil and paper can actually be applied to something you throw into your microwave.”</div>
 

 
 <div class="newsletter"></div>
 

 
 <div class="rich-text">And beyond piecing together the physics behind parlor tricks, the results could have implications for broader studies on plasma and light, says <a href="https://sites.lsa.umich.edu/biteen-lab/">Julie Biteen</a>, a biophysicist and chemist at the University of Michigan who was not involved in the study. One example is nanophotonics, or the study of light on the nanometer scale—another instance in which wavelengths are condensed into extremely small spaces. Nanophotonics can typically be visualized only with expensive microscopes. But the grape-microwave combination offers a way to tinker with these phenomena on a larger scale, with affordable everyday appliances.Replicating these effects with visible light will require some rejiggering, Bianucci says. But it’s a logical and exciting next step.<div style="padding-bottom: 56.25%;" class="responsive-object">
 <iframe width="480" height="270" src="https://www.youtube.com/embed/5zziS-2xd-k?feature=oembed" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</div>
In the meantime, it seems there are finally some answers to the mysteries behind the fiery wrath of these particular grapes. It’s worth noting, though, that the results didn’t necessarily come easy: The road to publication was littered with casualties—including a series of variably sized fruits and a dozen or so microwaves, each solemnly christened with a name to honor its sacrifices in the name of science (among the fallen microwaves were George I, George II, Jesús, Albert, and Thomas). One thing hasn’t changed: Plasma is a fickle and dangerous beast, not to be underestimated.Even Bianucci is loath to try this at home. “I’m waiting until my microwave gets really out of commission,” he says. With plasma in the picture, “you have to be careful about not melting a hole in the top of your microwave,” Khattak says. “I mean, you could give this a try, but I wouldn’t recommend it.”For the record, neither does NOVA.</div>

No kitchen appliances were harmed in the writing of this article.

Topic: Physics & Math

Hero Feature