Watch the launch of supersonic shockwaves from a bottle of champagne



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Opening a bottle of sparkling wine creates shock waves similar to those of supersonic escape of a fighter plane, according to a new study.

The split second of a champagne cork is created by a quick escape of high pressure gas long stuck in the neck of the bottle. Now, a group of researchers has used high-speed photography to visualize the chemistry behind this iconic pop.

For the experiment, they acquired six bottles of rosé champagne, two of which were kept at 30 degrees Celsius (86 degrees Fahrenheit) and two at 20 C (68 F) for three days. These bottles had been aged for 42 months and were undergoing what is called a "froth", a type of alcoholic fermentation. During this process, yeast feeds on sugar to create carbon dioxide, giving champagne its sparkle.

Related, connected, related: Sparkling Valentine's Day: 9 romantic facts about champagne

The researchers then used a high-speed camera to record when the plugs burst. The high-speed camera was connected to a microphone that recorded the detonation and pushed the camera to take a series of photos.

Here's what the scientists saw: when the cork came out of the bottle, it was violently pushed by carbon dioxide and the rapidly expanding water vapor, long confined in the neck of the bottle. This sudden change in pressure caused the cooling of the carbon dioxide and water vapor into ice crystals and the condensation into a mist that evaporated with the cork.

But to their surprise, researchers found that in the first millisecond of the cork, this sudden drop in pressure inside the bottle resulted in visible shock waves, called "Mach disks"These Mach disks, which are also created in the exhaust of fighter planes, are formed because the escaping gases spread through the air extremely quickly – at a speed twice that of the sound. disappear just as quickly when the pressure in the bottle returns to normal.

Mach disks are also forming in supersonic exhausts of combat aircraft, such as this McDonnell F-15E Strike Eagle.

Mach disks are also forming in supersonic exhausts of combat aircraft, such as this McDonnell F-15E Strike Eagle.

(Image credit: US Air Force / Senior Airman Matthew Bruch)

The formation of these Mach disks "was a big surprise," said lead author Gerard Liger-Belair, professor of chemical physics at the Reims Champagne-Ardenne University in France. "Physics [of Mach disks] was already known in aerospace engineering but not [at] everything in the science of champagne. "

In addition, researchers found that bottles stored at room temperature created a "noise" that was different from those stored at higher temperatures.

Since carbon dioxide is less soluble at higher temperatures, there is a greater amount of gas in the neck of bottles stored at warmer temperatures. Thus, the gas contained in the bottles stored at 30 ° C is subjected to a higher pressure than those stored at 20 ° C. When the cap in the bottle of 30 ° C is released, the pressure and temperature drop is greater than that of bottles stored at colder temperatures.

The hottest bottle creates large ice crystals and, thanks to the way these crystals disperse the light, a greyish white fog. The bottle at room temperature, on the other hand, creates smaller ice crystals, forming a more blue mist. "Let's hope that people will feel touched by the beautiful science hidden in a simple bottle of champagne or sparkling wine," said Liger-Belair.

The results were published on September 20 in the journal Progress of science.

Originally published on Science live.

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