TED-Ed

Explore the eye-opening science of LASIK: corrective laser eye surgery that focuses on reshaping the cornea to fix blurry vision.--In 1948, Spanish ophthalmologist Jose Ignacio Barraquer Moner was fed up with glasses. He wanted a solution for blurry vision that fixed the eye itself, without relying on external aids. The surgery he eventually devised was called “keratomileusis,” and his technique f...

Trace the history of how wolves, one of humanity’s oldest rivals, evolved into the domesticated dogs we call “man’s best friend.”--Since their emergence over 200,000 years ago, modern humans have established communities all over the planet. But they didn’t do it alone. Whatever corner of the globe you find humans in today, you’re likely to find another species as well: dogs. So how did one of our...

Learn how to identify, develop, and share your best ideas with TED Masterclass: http://bit.ly/tedmasterclass -- The average 20-year-old knows between 27,000 and 52,000 different words. Spoken out loud, most of these words last less than a second. With every word, the brain has a quick decision to make: which of those thousands of options matches the signal? And about 98% of the time, the brain cho...

View full lesson: http://ed.ted.com/lessons/how-does-your-brain-respond-to-pain-karen-d-davisOuch! Everyone experiences pain -- but why do some people react to the same painful stimulus in different ways? And what exactly is pain, anyway? Karen D. Davis walks you through your brain on pain, illuminating why the "pain experience" differs from person to person. Lesson by Karen D. Davis, animation by...

Practice more problem-solving at https://brilliant.org/TedEd/ --You’re a biologist on a mission to keep the rare honeybee Apis Trifecta from going extinct. The last 60 bees of the species are in your terrarium. You’ve already constructed wire frames of the appropriate size and shape. Now you need to turn them into working beehives by filling every hex with wax. Can you help the bees create produci...

Check out Lucy Cooke's "The Truth About Animals": https://bit.ly/TruthAboutAnimals --From Ancient Greece to the 20th century, Aristotle, Freud, and numerous other scholars were all looking for the same thing: eel testicles. Freshwater eels could be found in rivers across Europe, but no one had ever seen them mate and no researcher could find eel eggs or identify their reproductive organs. So how d...

View full lesson: http://ed.ted.com/lessons/mysteries-of-vernacular-robot-jessica-oreck-and-rachael-teelIn 1920, Czech writer Karel Čapek wrote a play about human-like machines, thereby inventing the term robot from the Central European word for forced labor. Jessica Oreck and Rachael Teel explain how the science fiction staple earned its name. Lesson by Jessica Oreck and Rachael Teel, animation b...

View full lesson: http://ed.ted.com/lessons/the-deadly-irony-of-gunpowder-eric-rosadoIn the mid-ninth century, Chinese chemists, hard at work on an immortality potion, instead invented gunpowder. They soon found that this highly inflammable powder was far from an elixir of life -- they put it to use in bombs against Mongol invaders, and the rest was history. Eric Rosado details how gunpowder has c...

Learn about the life and art of Mexican surrealist painter Frida Kahlo, who explored disability, relationships and Mexican culture in her work. --In 1925, Frida Kahlo was on her way home from school in Mexico City when the bus she was riding collided with a streetcar. She suffered near-fatal injuries and her disability became a major theme in her paintings. Over the course of her life, she would e...

Get to know the life of Mexican nun, poet and scholar, Sor Juana Inés de la Cruz, who was censored by the Church for her critical writings. --Juana Ramírez de Asbaje sat before a panel of prestigious theologians, jurists, and mathematicians. They had been invited to test Juana’s knowledge with the most difficult questions they could muster. But she successfully answered every challenge, from compl...

View full lesson: http://ed.ted.com/lessons/how-languages-evolve-alex-gendlerOver the course of human history, thousands of languages have developed from what was once a much smaller number. How did we end up with so many? And how do we keep track of them all? Alex Gendler explains how linguists group languages into language families, demonstrating how these linguistic trees give us crucial insigh...

Why, why, why does our education system look so similar to the way it did 50 years ago? Millions of students were failing then, as they are now -- and it's because we're clinging to a business model that clearly doesn't work. Education advocate Geoffrey Canada dares the system to look at the data, think about the customers and make systematic shifts in order to help greater numbers of kids excel....

Dig into the science and superstition behind the myth of vampires, and how it has persisted from ancient Mesopotamia to today.--The myth of the bloodsucking vampire has stalked humans from ancient Mesopotamia to 18th-century Eastern Europe, but it has differed in the terrifying details. So, how did we arrive at the popular image we know, love and fear today? And what truly makes a vampire...a vamp...

An animated interpretation of Tim Seibles' poem "First Kiss"--Watch an interview with the poet here: https://www.youtube.com/watch?v=Xiv3kKHpwk4This animation is part of our series, "There's a Poem for That," which features animated interpretations of poems both old and new that give language to some of life's biggest feelings. Check out the full series here: http://bit.ly/TEDEdTheresAPoemForThatP...

Bernie Krause has been recording wild soundscapes -- the wind in the trees, the chirping of birds, the subtle sounds of insect larvae -- for 45 years. In that time, he has seen many environments radically altered by humans, sometimes even by practices thought to be environmentally safe. A surprising look at what we can learn through nature's symphonies, from the grunting of a sea anemone to the sa...

View full lesson: http://ed.ted.com/lessons/a-digital-reimagining-of-gettysburg-anne-knowlesGeographer Anne Knowles uses digital technologies to reimagine the past. In this fascinating talk, Knowles transports us to the Battle of Gettysburg, the turning point of the Civil War. Using Geographic Information Systems (GIS) and historical maps, she traces the footsteps of Robert E. Lee as he orders Pic...

Download a free audiobook version of "The Three-Body Problem" and support TED-Ed's nonprofit mission: https://www.audible.com/ted-ed --In 2009, researchers ran a simple experiment. They took everything we know about our solar system and calculated where every planet would be up to 5 billion years in the future. They ran over 2,000 simulations, and the astonishing variety in results revealed that o...

Explore the psychology of the cognitive bias known as the conjunction fallacy, where we assume specific conditions are more probable than general ones. --Meet Lucy. She was a math major in college, and aced all her courses in probability and statistics. Which do you think is more likely: that Lucy is a portrait artist, or that Lucy is a portrait artist who also plays poker? How do we know which st...

Dive into the Irish myth of Táin Bò Cuailnge, where Queen Meadhbh of Connaught seeks to capture the fabled brown bull of Ulster. --Cú Chulainn, hero of Ulster, stood at the ford at Cooley, ready to face an entire army single handedly— all for the sake of a single bull. The army in question belonged to Queen Meadhbh of Connaught. Enraged at her husband’s possession of a white bull of awesome streng...

Trace the 9,000 year old history of the domestication of corn, or maize, and its effects on global agriculture. --Corn currently accounts for more than one tenth of our global crop production. And over 99% of cultivated corn is the exact same type: Yellow Dent #2. This means that humans grow more Yellow Dent #2 than any other plant on the planet. So how did this single variety of this single plant...

Until recently, many teachers only got one word of feedback a year: "satisfactory." And with no feedback, no coaching, there's just no way to improve. Bill Gates suggests that even great teachers can get better with smart feedback -- and lays out a program from his foundation to bring it to every classroom. Talk by Bill Gates. Learn more about your ad choices. Visit megaphone.fm/adchoices

Learn the techniques and tricks that pyramid schemes use to recruit new members and how to avoid being fooled yourself. --In 2004, a nutrition company offered a life-changing opportunity to earn a full-time income for part-time work. There were only two steps to get started: purchase a $500 kit and recruit two more members. By 2013, the company was making $200 million. There was just one problem -...

View full lesson: http://ed.ted.com/lessons/the-fundamentals-of-space-time-part-3-andrew-pontzen-and-tom-whyntieView part 1: http://ed.ted.com/lessons/the-fundamentals-of-space-time-part-1-andrew-pontzen-and-tom-whyntieView part 2: http://ed.ted.com/lessons/the-fundamentals-of-space-time-part-2-andrew-pontzen-and-tom-whyntieIn the first two lessons of this series on space-time, we've dealt with ob...

You don't need to plan an exotic trip to find creative inspiration. Just look up, says Gavin Pretor-Pinney, founder of the Cloud Appreciation Society. As he shares charming photos of nature's finest aerial architecture, Pretor-Pinney calls for us all to take a step off the digital treadmill, lie back and admire the beauty in the sky above. Talk by Gavin Pretor-Pinney. Learn more about your ad choi...

Dig into the false cause fallacy, which assumes that one event causes another, and learn how to distinguish between correlation and causation.--It’s 1843, and a debate is raging about one of the most common killers of women: childbed fever— no one knows what causes it. One physician has observed patients with inflammation go on to develop childbed fever, and therefore believes the inflammation cau...