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Popcorn’s explosive pop looks pretty cool in high-speed video, but just watching it with a regular camera doesn’t show everything that’s going on. If we take a look at it through schlieren optics, the kernel’s pop looks even more extraordinary:

The schlieren technique reveals density differences in the gases around the corn–effectively allowing us to see what is invisible to the naked eye. The popcorn kernel acts like a pressure vessel until the expansion of steam inside causes its shell to rupture. The first hints of escaping steam send droplets of oil shooting upward. The kernel may hop as steam pours out the rupture point, causing the turbulent billowing seen in the animation above. As the heat causes legs of starch to expand out of the kernel, they can push off the ground and propel the popcorn higher. As for the eponymous popping sound, that is the result of escaping water vapor, not the actual rupture or rebound of the kernel! See more of the invisible world surrounding a popping kernel in the video below. (Image credits: Warped Perception, source; Bell Labs Ireland, source; WP video via Gizmodo; BLI video submitted by Kevin)

Happy Halloween! 

Guncotton in a pumpkin and the decomposition of hydrogen peroxide catalysed by potassium iodide, on the roof of the Ri.

23 science facts we didn't know at the start of 2016

1. Gravitational waves are real. More than 100 years after Einstein first predicted them, researchers finally detected the elusive ripples in space time this year. We’ve now seen three gravitational wave events in total.

2. Sloths almost die every time they poop, and it looks agonising.

3. It’s possible to live for more than a year without a heart in your body.

4. It’s also possible to live a normal life without 90 percent of your brain.

5. There are strange, metallic sounds coming from the Mariana trench, the deepest point on Earth’s surface. Scientists currently think the noise is a new kind of baleen whale call.

6. A revolutionary new type of nuclear fusion machine being trialled in Germany really works, and could be the key to clean, unlimited energy.

7. There’s an Earth-like planet just 4.2 light-years away in the Alpha Centauri star system - and scientists are already planning a mission to visit it.

8. Earth has a second mini-moon orbiting it, known as a ‘quasi-satellite’. It’s called 2016 HO3.

9. There might be a ninth planet in our Solar System (no, Pluto doesn’t count).

10. The first written record demonstrating the laws of friction has been hiding inside Leonardo da Vinci’s “irrelevant scribbles” for the past 500 years.

11. Zika virus can be spread sexually, and it really does cause microcephaly in babies.

12. Crows have big ears, and they’re kinda terrifying.

13. The largest known prime number is 274,207,281– 1, which is a ridiculous 22 million digits in length. It’s 5 million digits longer than the second largest prime.

14. The North Pole is slowly moving towards London, due to the planet’s shifting water content.

15. Earth lost enough sea ice this year to cover the entire land mass of India.

16. Artificial intelligence can beat humans at Go.

17. Tardigrades are so indestructible because they have an in-built toolkit to protect their DNA from damage. These tiny creatures can survive being frozen for decades, can bounce back from total desiccation, and can even handle the harsh radiation of space.

18. There are two liquid states of water.

19. Pear-shaped atomic nuclei exist, and they make time travel seem pretty damn impossible.

20. Dinosaurs had glorious tail feathers, and they were floppy.

21. One third of the planet can no longer see the Milky Way from where they live.

22. There’s a giant, 1.5-billion-cubic-metre (54-billion-cubic-foot) field of precious helium gas in Tanzania.

23. The ‘impossible’ EM Drive is the propulsion system that just won’t quit. NASA says it really does seem to produce thrust - but they still have no idea how. We’ll save that mystery for 2017.

The brilliant colors of a soap film reveal the fluid’s thickness, thanks to a process known as thin film interference. The twisting flow of the film depends on many influences: gravity pulls down on the liquid and tends to make it drain away; evaporation steals fluid from the film; local air currents can push or pull the film; and the variation in the concentration of molecules – specifically the surfactants that stabilize the film – will change the local surface tension, causing flow via the Marangoni effect. Together these and other effects create the dancing turbulence captured above. (Video credit: A. Filipowicz)

The first of the 2016 science Nobel Prizes was announced earlier today. The prize for Medicine or Physiology was awarded to Yoshinori Ohsumi for his work on the mechanisms behind autophagy. Find out more about his Nobel-winning work with this graphic! http://bit.ly/NobelSci2016

a mushroom rainbow to put the fun in fungi. cause they don’t need psilocybin to be magic. and though some mushrooms are coloured as a toxicity warning to predators, many others are brightly coloured to instead attract potential spore dispersers. see this for more on the bioluminescent mushrooms seen here. (photos)

Quote by #rosalindfranklin How do you make science a part of your life? What are you doing to fight for scientific literacy? More quotes and questions in my #ilovescience journal. #womeninscience #scientificliteracy

Gertrude B. Elion: Women who changed science

With the drugs that she created, Gertrude Elion fulfilled her life’s mission: to alleviate human suffering. Beyond the individual drugs she discovered, she pioneered a new, more scientific approach to drug development that forever altered – and accelerated – medical research. 

Discover her story at 

https://www.nobelprize.org/womenwhochangedscience/stories

(Image caption: Brandeis University professor Ricardo Godoy conducts the experiment in a village in the Bolivian rainforest. The participants were asked to rate the pleasantness of various sounds, and Godoy recorded their response. Credit: Alan Schultz)

Why we like the music we do

In Western styles of music, from classical to pop, some combinations of notes are generally considered more pleasant than others. To most of our ears, a chord of C and G, for example, sounds much more agreeable than the grating combination of C and F# (which has historically been known as the “devil in music”).

For decades, neuroscientists have pondered whether this preference is somehow hardwired into our brains. A new study from MIT and Brandeis University suggests that the answer is no.

In a study of more than 100 people belonging to a remote Amazonian tribe with little or no exposure to Western music, the researchers found that dissonant chords such as the combination of C and F# were rated just as likeable as “consonant” chords, which feature simple integer ratios between the acoustical frequencies of the two notes.

“This study suggests that preferences for consonance over dissonance depend on exposure to Western musical culture, and that the preference is not innate,” says Josh McDermott, the Frederick A. and Carole J. Middleton Assistant Professor of Neuroscience in the Department of Brain and Cognitive Sciences at MIT.

McDermott and Ricardo Godoy, a professor at Brandeis University, led the study, which appeared in Nature on July 13. Alan Schultz, an assistant professor of medical anthropology at Baylor University, and Eduardo Undurraga, a senior research associate at Brandeis’ Heller School for Social Policy and Management, are also authors of the paper.

Consonance and dissonance

For centuries, some scientists have hypothesized that the brain is wired to respond favorably to consonant chords such as the fifth (so-called because one of the notes is five notes higher than the other). Musicians in societies dating at least as far back as the ancient Greeks noticed that in the fifth and other consonant chords, the ratio of frequencies of the two notes is usually based on integers — in the case of the fifth, a ratio of 3:2. The combination of C and G is often called “the perfect fifth.”

Others believe that these preferences are culturally determined, as a result of exposure to music featuring consonant chords. This debate has been difficult to resolve, in large part because nowadays there are very few people in the world who are not familiar with Western music and its consonant chords.

“It’s pretty hard to find people who don’t have a lot of exposure to Western pop music due to its diffusion around the world,” McDermott says. “Most people hear a lot of Western music, and Western music has a lot of consonant chords in it. It’s thus been hard to rule out the possibility that we like consonance because that’s what we’re used to, but also hard to provide a definitive test.”

In 2010, Godoy, an anthropologist who has been studying an Amazonian tribe known as the Tsimane for many years, asked McDermott to collaborate on a study of how the Tsimane respond to music. Most of the Tsimane, a farming and foraging society of about 12,000 people, have very limited exposure to Western music.

“They vary a lot in how close they live to towns and urban centers,” Godoy says. “Among the folks who live very far, several days away, they don’t have too much contact with Western music.”

The Tsimane’s own music features both singing and instrumental performance, but usually by only one person at a time.

Dramatic differences

The researchers did two sets of studies, one in 2011 and one in 2015. In each study, they asked participants to rate how much they liked dissonant and consonant chords. The researchers also performed experiments to make sure that the participants could tell the difference between dissonant and consonant sounds, and found that they could.

The team performed the same tests with a group of Spanish-speaking Bolivians who live in a small town near the Tsimane, and residents of the Bolivian capital, La Paz. They also tested groups of American musicians and nonmusicians.

“What we found is the preference for consonance over dissonance varies dramatically across those five groups,” McDermott says. “In the Tsimane it’s undetectable, and in the two groups in Bolivia, there’s a statistically significant but small preference. In the American groups it’s quite a bit larger, and it’s bigger in the musicians than in the nonmusicians.”

When asked to rate nonmusical sounds such as laughter and gasps, the Tsimane showed similar responses to the other groups. They also showed the same dislike for a musical quality known as acoustic roughness.

The findings suggest that it is likely culture, and not a biological factor, that determines the common preference for consonant musical chords, says Brian Moore, a professor of psychology at Cambridge University, who was not involved in the study.

“Overall, the results of this exciting and well-designed study clearly suggest that the preference for certain musical intervals of those familiar with Western music depends on exposure to that music and not on an innate preference for certain frequency ratios,” Moore says.

Archbishop Ussher’s chronology was taken as gospel in the Western world. Until we turned to another book to find the age of the earth, the one that was written in the rocks themselves.