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SciShow News explains the amazing discoveries behind this year’s Nobel Prizes, from the invention that made LED bulbs possible to discovering how our “inner GPS” works!

Hosted by: Hank Green
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Sources:
http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/popular-physicsprize2014.pdf

http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/press.html


http://www.nobelprize.org/nobel_prizes/medicine/laureates/2014/press.html

http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2014/popular-chemistryprize2014.pdf*
http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/popular-physicsprize2014.pdf*

http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2014/press.html

http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/press.html
[Intro]   How do we see what's inside us? How do you see me? How do I know where I'm going? These are some of the questions answered by the brightest minds in the word, 2014's Nobel Prize winners in physics, medicine, and chemistry.   First, the Nobel Prize for physics, it went to Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura for developing the blue light emitting diode, or LED. This ridiculously useful invention is the key to making possible the white LED bulb. Which is replacing Thomas Edison's incandescent bulb as the the light source of the 21st century. LEDs are also in smartphones, and television screens, and laptop screens, and desktop screens. Probably if the LEDs in your computer turned off right now, I would disappear. And I wouldn't have a job!    An LED is a type of diode or semiconductor device that emits light when electrons flow through layers of crystalline inorganic material. These diodes have been around since the 1950s, but at first we were only able to make ones that emitted either red or green light. And those were still super useful; you've no doubt seen them in watches, and calculators, and all those little red lights on answering machines - if you remember what answering machines are. But the challenge was always to build a diode that emitted white light. And that required creating a combination of diodes that together glowed in red, green, and blue. The problem was blue light has a much shorter wavelength than red and green light. And scientists struggled for decades to find a material that emitted light in that wavelength when electrons based through it. It was until the 1980s that these three laureates developed a high quality layer of crystalline gallium nitrate that did the trick.    Today, white LED bulbs are everywhere and for good reason. They're a lot more energy efficient than incandescent bulbs which lose a lot of their energy through heat. LEDs convert electricity directly into light, which means they need less power. And considering that a fourth of the world's total energy output is spent on generating light, these scientists deserve the prize as clearly as you're seeing me right now.    For the winners of this year's chemistry prize, light posed a different kind of challenge. For centuries, scientists have been limited by the fact that optical microscopes couldn't achieve a resolution smaller than 0.2 micrometers, or half the wavelength of visible light. This has to do with how light diffuses through a microscope's glass lens and was known as Abbe's Diffraction Limit. This limit meant that we could clearly see living cells, but we couldn't see individual molecules or proteins inside them. So in the 1980s and 90s, scientists began experimenting with fluorescent microscopy. Using gene-splicing technology to introduce fluorescent, or glowing, molecules into a cell. These molecules could then couple with DNA and proteins to act as a kind of tracer. And that was extremely helpful, but it didn't solve the problem of seeing things that were smaller than 0.2 micrometers. But this year's chemistry winners came up with ways to break Abbe's limit by inventing ways to turn fluorescence of those molecules on or off, like a switch. Making them clearly visible.   German chemist Stefan Hell did this by using lasers. Essentially to turn on all of the glowing molecules within a single nanometer; that's a billionth of a meter. By slowly passing the lasers over a cell, nanometer by nanometer, he was able to create a detailed image of a cell by highlighting groups of glowing molecules. At the same time, two US scientists, Eric Betzig and William Moerner, developed a similar technique that uses pulses of light to turn individual molecules on and off. Allowing them to clearly stand out in the specimen. Like with Hell's technique, they could repeat this process lighting up different molecules until they eventually created a super high resolution image of structures as thin as a cell membrane. Together these techniques gave the world what's now known as super-resolved fluorescence microscopy, allowing us to see what goes on inside a living cell with visible light.   Finally, we have the winners of this year's prize in medicine. John O'Keefe, May-Britt Moser, and Edvard Moser who discovered that brains have an inner GPS that tells animals, including us, where they are. O'Keefe discovered the first clues to this system in 1971 while studying rats. He noted that certain neurons in the upper hippocampus, the region of the brain responsible for memory and organization, were always activated when a rat was in a particular place in a room. O'Keefe named these neurons "place cells". As the rat moved around the room, different "place cells" would fire. Through further research, O'Keefe concluded that these cells were responsible for building and storing mental maps. Then in 2005, May-Britt and Edvard Moser conducted their own rat experiments and discovered another set of neurons called "grid cells". They're located in a part of the brain called the entorhinal cortex, right next to the hippocampus, and they're what your brain uses to create a map-like grid of any environment. The Mosers discovered that these cells would not only fire whenever a rat passed a particular location, but they would go off again when it pointed its head in the direction of that spot.    Together, these newly discovered sets of cells basically make up the iPhone map in your brain that you use to get around. O'Keefe's "place cells" form the coordinates on that map, while the Mosers' "grid cells" create the little blue dot on the map that tells you where you are.    So thanks to this year's Nobel laureates for helping us see life at the microscopic level, understand how we know where we are, and for making it possible for you to see me right now. Thanks for watching this episode of SciShow News. If you want us help us educate the world on the awesomeness of science, which we couldn't do without support from people like you, you can become a supporting subscriber at subbable.com/scishow. And if you just want to keep getting smarter with us, you can go to youtube.com/scishow and subscribe.