It's Fourth of July weekend in the US, so our American readers are hopefully enjoying the long weekend away from the Internet. For everyone else, Jen-Luc Piquant has her usual round of nifty physics-related links gleaned from the past week of Web surfing.

First up in a bunch of holiday-themed links: Hidden vortices! The Science (fluid dynamics, to be specific) Of Amber Waves Of Grain. Also: How much ice do you need to cool your beer? Related: Science on Tap: What Makes the Perfect Beer Foam? Discovery News wonders: Are the Moon's American Flags Still in Good Shape? Related: There are Invisible Blue-Jean Particles in the Original Star-Spangled Banner. Also, my fellow SciAm blogger David Bressan has a two-part post on Geology and Generals: How Geology influenced the Battle of Gettysburg (Part I and Part II.) Finally, TED-Ed summarized What you might not know about the Declaration of Independence.

Still, what you really want to know is just what’s Happening Inside Those 4th of July Fireworks, science-wise. Aerial fireworks are essentially semi-controlled exploding rockets, whlie Rhett Allain of Dot Physics discusses The Awesome Physics in a Simple Sparkler. Check out Boom City, a Photographic series of Firework Cross Sections That Reveal Their Colorful Contents. This Is What Daytime Fireworks Look Like, and this is How Fireworks Inscribe The Sky. Finally, what about the Chemistry of Fireworks? Washington College professor John Conkling breaks down the science of fireworks shows:

Related: This supermassive black hole created an awesome 'fireworks display' in space. Also: Why Bother With Ordinary Fireworks When You Can Have Black Hole Fireworks? Maybe they pop off like firecrackers.

Sadly the United States has been eliminated from the World Cup, but there's still plenty of games still to go -- and plenty of science-y related posts apparently. For instance, how do you block a penalty kick? With physics, that's how! Related: Holland's fear of the penalty kick: the statistics behind the art and science of the perfect penalty. Bonus: Here Are Your World Cup Highlights As Portrayed by Cats.

But you know, it's not all soccer, soccer, soccer (or football, football, football, per the rest of the world). There's also tennis at this year's Wimbledon tournament, and that means.... Tennis Physics! Smashing success: the science behind Nick Kyrgios' serve.

June 28 was The Most Mathematically Perfect Day of the Year. "A perfect number [is] the sum of its factors besides itself."

In space news, NASA Declared its Test for Its Warehouse-Sized, Mars-Bound Parachute. According to JPL's Mark Adler: "It worked beautifully."

Here's the current status for the BICEP2 outlook: "the Earthquakes are.. in the lead and favored to win. Conceivably, the Galaxy can make a comeback." A Bold Critic of BICEP2, the Big Bang’s ‘Smoking Gun’: David Spergel explains why a widely publicized gravitational-wave discovery could be wrong, and how it could affect the public’s perception of science. Meanwhile, Chao-Lin Kuo, who helped design the BICEP2 experiment, isn’t bothered by criticism that cosmic dust may account for his results. He just wants to know the truth. And here's an excellent idea: BICEP2 and Planck are talking about sharing their data. "We're still discussing the details but the idea is to exchange data between the two teams and eventually come out with a joint paper."

Related: There was a profile of cosmologist (and inflationary theory pioneer) Alan Guth in National Geographic: "I think science is going to require more and more patience from society than it has in the past."

And here's Sean Carroll (a.k.a. the Time Lord) explaining why you should accept that quantum mechanics is a theory of many worlds.

Fabergé Fractals: Former laser physicist Tom Beddard has turned his hand to creating incredible pieces of art that celebrate the beauty and intricacy of fractals. Per Beddard:

"The 3D fractals are generated by iterative formulas whereby the output of one iteration forms the input for the next. The formulas effectively fold, scale, rotate or flip space. They are truly fractal in the fact that more and more detail can be revealed the closer to the surface you travel.

The fascinating aspect is where combinations of parameters can combine to create structural 'resonances' of extraordinary detail and beauty—sometimes naturally organic and other times perfectly geometric. But then like a chaotic system it can completely disappear with the smallest perturbation."

Watch Beddard's work in action:

More fun with fractals: Play the Chaos Game! "A simple game with a die, a triangle, and a hell of a lot of patience, can help you to draw a famous fractal."

Catching a nearby supernova could give scientists a glimpse into physics they could never recreate on Earth.

Relaxation and repulsion help viruses pack DNA.

Physics and Dance go together remarkably well if you’re creative about blending the curriculum.

Neil deGrasse Tyson, High School Wrestling Team Captain, Invented a Physics-Based Wrestling Move.

Better Engineering Through Urine -- You're Welcome, Isaac Newton. "We can't prove Sir Isaac Newton was thinking about how animals urinate when he was developing his laws of gravity but he can't prove he wasn't either. What we can prove is that they are connected – by the urethra, to be specific."

A guide to bioluminescence: "All around the world, oceans glow, trees sparkle, and the forest floor flashes."

More interesting than watching nail polish dry: why some types of manicures require UV light.

Meet Frederick Rogers, The Engineer Who Said The Ark Of The Covenant Was A Giant Capacitor in 1933. "The question of whether it was sufficient to melt Nazi's faces was not addressed."

Landscapes and Cityscapes Rendered as Musical Notes by Japanese artist Koshi Kawachi. "[Kawachi] started by tracing the ridge lines of mountains and cityscapes, taking each point and replacing it with an appropriate musical note."

New Measurements Confirm That the Universe Is Boring: "No special places, no special directions."

Ancient Japanese gold leaf artists worked on a nanoscale. "An analysis of six ancient Namban paper screens show that these artifacts are gilded with gold leaf that was hand-beaten to the nanometer scale."

A new theory explains how some crystals block the flow of heat, contrary to textbook physics.

The ghosts and the machine: Studying the diaphanous neutrino will be America’s contribution to a new generation of physics.

The speed of light compared to the fastest objects known to humanity, in an infographic.

Physicist Michael Kelsey shares do-it-yourself expertise online.

Does polarised glass have to be tinted? The physics behind your sunglasses.

The Scientific Problem That Must Be Experienced: To understand turbulence we need the intuitive perspective of art. For example: "Contemporary Japanese artist Goh Shigetomi [see image, right] stands in streams and, moved by the right moment, disperses black ink into the water so that it can imprint an image of the flow on paper. The water 'spontaneously draws lines,' he says."

Related: To Predict Turbulence, Just Count the Puffs: These tiny swirls of fluid live, die, reproduce, and spark turbulence.

Faking Galileo, a new book about "a clever forgery of Galileo’s landmark book Sidereus Nuncius, published in Venice in 1610. Arguably one of the most extraordinary scientific publications of all times, Sidereus Nuncius turned Galileo into the brightest new star of Western science. Four centuries later, a faked copy of this book has disarmed a generation of Galileo experts, and raised a host of intriguing questions about the social nature of scholarly authentication, the precariousness of truth, and the revelatory power of fakes."

Cloaking from earthquakes? "[I]f [an invisibility] cloak can be designed to deflect light waves, it stands to reason, then why not other types of waves, or fields? Magnetic fields could be deflected, to protect sensitive electronics within. Water waves could be deflected, to protect offshore platforms or buoys from damaging waves during extreme storms. Or, maybe — just maybe — seismic waves from earthquakes could be guided around vulnerable buildings."

Something squee-worthy for fans of the film Apollo 13: This is the actual hack that saved the astronauts of the Apollo XIII. You remember the scene...

'Unique' Meteorite Likely Came From Long-Dead Asteroid.

Astronomy's "Cinderella" Caroline Herschel is featured on Stuff You Missed in History Class podcast.

Statistics is more than a numbers game – it underpins all sciences.

Could Antigravity Explain Away Dark Matter and Dark Energy? tl;dr: probably not, but a physicist has an intriguing hypothesis, as physicists are wont to do. "A pair of researchers at Italy's Astrophysical Observatory of Turin are claiming a practical method to gather evidence for a whole new cosmological model." Related: Dark Matter could be thought of as a Wave Instead Of a Particle. "Dark matter is considered a theory because it has to exist - it just isn't defined."

What’s next for Higgs boson research? Two years after the groundbreaking discovery, physicists are still hard at work.

The Universe is big and you’re small but this animation should reassure you. "It’s not all bad, you’re connected to larger forces in the universe than you imagined."

Light has limits, even for elves. How far could Legolas actually see? (h/t: Nerdist)

This Doctor Who-Adventure Time Mashup Is Positively Mathematical - Wibbly wobbly, cutesy wutesy.

"Good news: "stock-photo-blackboard consultant" is clearly a vacant niche for an enterprising physics student."

The most basic unknowable property of matter. Or, Quantum mechanics ruins everything.

Sandia Labs Hands Bomb-Detecting Miniaturized Synthetic Aperture Radar Tech Over To Army.

Not Only Top Quark Asymmetry: Bottom Quark Asymmetry Measured By CDF.

NASA carbon observatory finally reaches space: Let the CO2 hunt begin. "[B]y the end of the month it should be fully launched on its scientific mission: taking more than 100,000 precise measurements of carbon dioxide in the Earth's atmosphere every day." Related: A Behind The Scenes Look At NASA's New Carbon-Tracking Satellite.

Doomed Stars May Test Einstein’s Relativity. Related: Baby Stars are Ripping Their Stellar Nursery to Shreds. Also: Untrasound For Baby Stars: Determining Age By Sound Waves.

Jacobi Iterative Method: 19th Century Math Gets A 21st Century Makeover.

Nanofluids And A Microchannel Heat Sink: A New Way To Keep Electronics From Overheating.

Cosmic Rays, Neutrons, and the Mutation Rates in Evolution. If background levels of neutron radiation can explain errors in computer memory, then it should also explain errors in DNA replication.

Nanoparticles, laser cleaning, and glue-eating bacteria restore valuable frescoes and paintings.

Eruptions from the sun at three different wavelengths produced this stunning image (right).

Enjoy A Bottle Of Jupiter With These Planet-Inspired Microbrews.

Five insights challenging science's unshakable 'truths.'

Quantum Computing 101 with D-Wave's Vern Brownell.

Curiosity Has Made Some Truly Amazing Discoveries in Its First Martian Year.

Heisenberg's Uncertainty Principle: Conjugate Variables And Compressive Sensing.

Agnes Clerke - an intense light on Victorian astronomy. She "was one of a small cluster of Victorian ladies of astronomy in London. The assessment of one of these, her friend Lady Margaret Huggins, was that, ‘No purer, loftier and yet sweetly unselfish and human soul has lived...’"

The hard data on UFO sightings: it's mostly drunk people in the West. (At least that's one interpretation.) Related: What does alien life look like? And what are the odds that it’s out there?

Fantastically Wrong: Cyrus Reed Teed, The Legendary Scientist Who Swore Our Planet Is Hollow.

Why Do Mountain Climbers Waste Away? What happens at high altitude may help patients in the ICU.

Thirty Meter Telescope Inching Towards Final Approval: An update on the telescope controversy in Hawai'i.

The influence of John Holdren, a physicist and White House science adviser, can be seen in a number of policies.

It's Mathemagical! In Which Vi Hart Explains Why Some Infinities Are Bigger Than Others: