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Duration:04:46
Uploaded:2014-01-18
Last sync:2018-12-02 11:40
Hank shares the latest developments in science, this week demystifying three freaky things in nature: the polar vortex, why some bugs are infertile, and how a chain can appear to defy gravity. You're welcome!

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Sources:
chain fountain
http://youtu.be/_dQJBBklpQQ
http://rspa.royalsocietypublishing.org/lookup/doi/10.1098/rspa.2013.0689
https://press.royalsociety.org/Uploads/RSPA20130689p.pdf [MEDIA USE ONLY]

polar vortex
http://www.pmel.noaa.gov/arctic/atmosphere/polar_vortex_2014.html
http://www.arctic.noaa.gov/detect/climate-strat.shtml
http://www.arctic.noaa.gov/future/warm_arctic_cold_continent.html

bug sex
www.sciencemag.org

 Intro (0:00)


Hello, I'm Hank Green, and welcome to Scishow News. 
Now, if you live in North America, your holidays might have been interrupted by a little something called The Polar Vortex; which has been blamed for sending Arctic air as far south as Texas, creating frost quakes, giant, crazy balls of ice in the Great Lakes and delighting mean-makers everywhere. 

 Polar Vortex (0:30)


The Polar Vortex is not an event, and it's not something that TV weather folks just came up with. It's been studied by climate scientists for decades, actually, I think it was first identified in the 1800s.
Strictly speaking, this polar vortex that dipped down into the US this year is the whirl of wind that flows from to west to east and encircles the North Pole. The stronger these winds run, the colder they get and the better they are at keeping frigid air around the pole. 
But sometimes, the vortex slows down and starts to waver, allowing Arctic air to break south, to lower latitudes, while also cycling warmer air back north. So, the infusion of icy air that many of us experienced wasn't just a one time thing, this winter is shaping up to be a weak polar vortex season. The last really serious one was in 2009, when North America, Europe and Northern Asia all saw record cold and snow. And scientists don't know what causes these variations, but they're forecasting another dip of Arctic air to visit North America this week. It's important to know that this isn't The Polar Vortex, it's just a polar vortex. There's one around the North Pole and the South Pole. There's one also around the North Pole of Saturn and the South Pole of Saturn, Jupiter and, like, all of the other planets. It's just caused by the difference in air temperatures between the equators and the poles, and it's a normal thing that happens on planets. It's not weird!

 Bug Sex (1:47)


Next, we finally have an explanation for one of the most unfair things in the animal kingdom: why some insects aren't allowed to have sex. Lots of insects, like bees, wasps and ants have a special class of workers in their colonies who are incapable of mating, so only the Queen can produce offspring. This week, in the Journal of Science, biologists report that they figured out how workers are made sexless. It turns out that Queens are capable of secreting chemicals that block the sexual development of the workers around them. Kinda like a reverse pheromone. The researchers experimented with Desert Ants, Common Wasps and Buff-Tailed Bumblebees, and found that the Queen of each species released the same kind of chemical: a saturated hydrocarbon. While the exact recipe for this compound was slightly different for each species, the results were the same. Workers that were exposed to the chemical, even when the Queen wasn't present, became infertile. However, workers that were kept separate from their Queens quickly started to grow sex organs. And good for them! Because the chemicals appear in such different kinds of insects, scientists think that this method of sexual control make have been used by bugs for a hundred and fifty million years.

 Chain Fountain (2:53)


Finally, lets explore  a phenomenon of physics that gained fame right here on YouTube. One so perplexing that a team of physicists has just published a study that tries to explain it. If you haven't seen it before, let me introduce you to the marvel known as The Chain Fountain. Last year, BBC science guy Steve Mould posted this video of a chain of small metal beads that, when one end is dropped from a jar, falls to the ground, not in the shortest path possible, as you might expect, but in an arc. This week, a team of British physicists published a study in the Proceedings of the Royal Society A, that tries to demystify The Chain Fountain. It suggests that the chain in powered partly by a simple reaction force, a function of Newton's Third Law of Motion, that for every action there is an equal and opposite reaction. The team explains how it works by describing a single link in the chain at rest in the jar. As one end of the chain gets lifted up by the falling chain, the other end is naturally driven downward, like a see-saw. That's the equal and opposite reaction. But as the link is lying flat in the jar, that end can't move down. Instead, the downward pressure serves to push the link upward. The stronger the pull on one end of the chain, the stronger the push upward on the next, giving the chain extra lift. So, in the end, the scientists say The Chain Fountain is the result of the chain being pulled into motion and also being pushed into motion by the pile and the jar beneath it. My mind, blown!

 Outro (4:16)


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