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Hammer and Feather Drop on the Moon

In 1971, astronaut David Scott conducted Galileo's famous hammer/feather drop experiment on the moon, during the Apollo 15 mission. Galileo had concluded that all objects, regardless of mass, fall at the same speed -- however, the resistance caused by the air (as in the case of the feather in Earth's atmosphere) can cause the feather to drop slower. Well, on the moon there is no atmosphere (a vacuum), so the objects should drop at the same speed. See for yourself how the experiment turned out in the video below.

As Mission Controller Joe Allen wrote in the Apollo 15 Preliminary Science Report:

During the final minutes of the third extravehicular activity, a short demonstration experiment was conducted. A heavy object (a 1.32-kg aluminum geological hammer) and a light object (a 0.03-kg falcon feather) were released simultaneously from approximately the same height (approximately 1.6 m) and were allowed to fall to the surface. Within the accuracy of the simultaneous release, the objects were observed to undergo the same acceleration and strike the lunar surface simultaneously, which was a result predicted by well-established theory, but a result nonetheless reassuring considering both the number of viewers that witnessed the experiment and the fact that the homeward journey was based critically on the validity of the particular theory being tested.

Joe Allen, NASA SP-289, Apollo 15 Preliminary Science Report, Summary of Scientific Results, p. 2-11

Here's video of the experiment:

Ever since the hammer/feather drop in 1971, moon-hoax conspiracy theorists have been trying to prove that this footage was faked. Here's one video that claims to disprove NASA's experiment. I encourage you to read the YouTube comments on that hoax video for an entertaining nerd-fight. See also: high-resolution video of the experiment from NASA, and a mathematical discussion of the physics involved.

(Via Kottke.org.)

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science
Why Adding Water to Your Whiskey Makes It Taste Better
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iStock

Don’t ever let people tease you for watering down your whiskey. If they’re true aficionados, they’ll know that adding a splash of water or a few cubes of ice to your drink will actually enhance its natural flavors. But how can something as flavorless as water make a barrel-aged scotch or bourbon taste even better? Chemists think they’ve found the answer.

As The Verge reports, researchers from the Linnæus University Centre for Biomaterials Chemistry in Sweden analyzed the molecular composition of whiskey in the presence of water. We already know that the molecule guaiacol is largely responsible for whiskey’s smoky taste and aroma. Guaiacol bonds to alcohol molecules, which means that in straight whisky that guaiacol flavor will be fairly evenly distributed throughout the cask. Alcohol is repelled by water, and guaiacol partially so. That means when a splash of the water is added to the beverage the alcohol gets pushed to the surface, dragging the guaiacol along with it. Concentrated at the top of the glass, the whiskey’s distinctive taste and scent is in the perfect position to be noticed by the drinker.

According to the team’s experiments, which they laid out in the journal Scientific Reports [PDF], whiskey that’s been diluted down to 40 percent to 45 percent alcohol content will start to show more guaiacol sloshing near the surface. Most commercial whiskey is already diluted before it's bottled, so the drink you order in a bar should fall within this range to begin with. Adding additional water or ice will boost the flavor-enhancing effect even further.

As for just how much water to add, the paper doesn’t specify. Whiskey lovers will just have to conduct some experiments of their own to see which ratios suit their palate.

[h/t NPR]

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Gray, George Robert; Hullmandel & Walton; Hullmandel, Charles Joseph; Mitchell, D. W / Public Doman
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Animals
DNA Tests Show ‘Extinct’ Penguin Species Never Existed
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Gray, George Robert; Hullmandel & Walton; Hullmandel, Charles Joseph; Mitchell, D. W / Public Doman

Science is a self-correcting process, ever in flux. Accepted hypotheses are overturned in the face of new information. The world isn’t flat after all. Disease isn’t caused by demons or wickedness. And that Hunter Island penguin? Yeah, apparently that was just a figment of our imaginations. Researchers writing in the Zoological Journal of the Linnean Society say the remains of one supposed species are in fact a “jumbled mixture” of bones from three extant species.

The bones were unearthed in the 1980s during the excavation of a prehistoric trash heap on Tasmania’s Hunter Island. Two scientists named Tets and O’Connor argued that the remains were different enough from other penguins to constitute their own genus and species, one which must have died out during the Holocene epoch. The proud potential penguin parents dubbed the apparently extinct bird Tasidyptes hunterivan, and that was that.

Except that this is science, where no story is ever really over. Other biologists were not satisfied with the evidence Tets and O’Connor presented. There were only four bones, and they all bore some resemblance to species that exist today. Fortunately, in 2017, we’ve got ways of making fossils talk. A research team led by Tess Cole of the University of Otago used DNA barcoding to examine the genetic code of each of the four bones.

“It was a fun and unexpected story,” Cole said in a statement, “because we show that Tasmania’s ‘extinct' penguin is not actually an extinct or unique penguin at all.”

Snares penguins dive into the water.
Snares penguins (Eudyptes robustus).
Brocken Inaglory, Wikimedia Commons // CC BY-SA 3.0

The bones were “a jumbled mixture of three living penguin species, from two genera": the Fiordland crested penguin or Tawaki (Eudyptes pachyrhynchus) and the Snares crested penguin (Eudyptes robustus), both of New Zealand, and the Australian little fairy penguin (Eudyptula novaehollandiae).

“This study shows how useful ancient DNA testing can be,” Cole said. “Not only does it help us identify new but extinct species, but it can help us rule out previously postulated species which did not exist, as in this case.”

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