TED-Ed

Dive into the history of the life-saving procedure of blood transfusions and how it has evolved since the 17th century. --In 1881, doctor William Halsted rushed to help his sister Minnie, who was hemorrhaging after childbirth. He quickly inserted a needle into his arm, withdrew his own blood, and transferred it to her. After a few uncertain minutes, she began to recover. What made this blood trans...

Uncover the history of the witch hunts that swept through Europe and the American colonies from the 15th century until the 18th century.--In the German town of Nördlingen in 1593, innkeeper Maria Höll found herself accused of witchcraft. She was arrested for questioning, and denied the charges. She insisted she wasn’t a witch through 62 rounds of torture before her accusers finally released her. O...

View full lesson: http://ed.ted.com/lessons/the-moon-illusion-andrew-vanden-heuvelHave you noticed how the full moon looks bigger on the horizon than high overhead? Actually, the two images are exactly the same size -- so why do we perceive them differently? Scientists aren't sure, but there are plenty of intriguing theories. Andrew Vanden Heuvel unravels the details of focus, distance and proport...

View full lesson: http://ed.ted.com/lessons/vs-ramachandran-the-neurons-that-shaped-civilizationNeuroscientist Vilayanur Ramachandran outlines the fascinating functions of mirror neurons. Only recently discovered, these neurons allow us to learn complex social behaviors, some of which formed the foundations of human civilization as we know it. Talk by VS Ramachandran. Learn more about your ad choi...

View full lesson: http://ed.ted.com/lessons/the-case-of-the-vanishing-honeybees-emma-bryceIn the past decade, the US honeybee population has been decreasing at an alarming and unprecedented rate. While this is obviously bad news for honeypots everywhere, bees also help feed us in a bigger way -- by pollinating our nation's crops. Emma Bryce investigates potential causes for this widespread colony...

View full lesson: http://ed.ted.com/lessons/rachel-pike-the-science-behind-a-climate-headlineIn 4 minutes, atmospheric chemist Rachel Pike provides a glimpse of the massive scientific effort behind the bold headlines on climate change, with her team -- one of thousands who contributed -- taking a risky flight over the rainforest in pursuit of data on a key molecule. Talk by Rachel Pike. Learn more...

Explore the history of the notorious United Fruit Company and how its influence over the banana industry impacted Central America. --In December 1910, the exiled former leader Manuel Bonilla boarded a borrowed yacht and set sail for Honduras in hopes of reclaiming power by whatever means necessary. Bonilla had a powerful backer: the notorious organization known throughout Latin America as “El Pulp...

Pop quiz: When does learning begin? Answer: Before we are born. Science writer Annie Murphy Paul talks through new research that shows how much we learn in the womb -- from the lilt of our native language to our soon-to-be-favorite foods. Talk by Annie Murphy Paul. Learn more about your ad choices. Visit megaphone.fm/adchoices

Dive into the world of aquaculture and see how restorative ocean farming could play a vital role in helping our coastal communities, our oceans and our climate. --For billions of people, seafood provides a significant source of protein and nutrition, but over half the seafood we eat isn’t caught in the wild, it’s grown through aquaculture. Farmed seafood is one of the fastest-growing food industri...

Discover the dormant army of billions of cicadas that emerge from underground every 13 or 17 years to molt, mate, and die. --Every 13 or 17 years, billions of cicadas emerge from the ground to molt, mate and die. Adult cicadas only live a few weeks above ground, but you'd be hard pressed to ignore them -- they are extremely loud! Rose Eveleth explains everything you need to know about these noisy...

Political prisoners aren't the only ones being tortured -- the vast majority of judicial torture happens in ordinary cases, even in 'functioning' legal systems. Social activist Karen Tse shows how we can, and should, stand up and end the use of routine torture. Talk by Karen Tse. Learn more about your ad choices. Visit megaphone.fm/adchoices

Explore the strategies investors use to choose stocks and learn whether it’s better to be an active or passive investor. --Every day, billions of stocks are traded on the New York Stock Exchange alone. But with over 43,000 companies listed on stock exchanges around the world, how do investors decide which stocks to buy? And what do individuals and institutions achieve by investing in stocks? Richa...

Dig into the science of how anabolic steroids and their recreational use can affect your body, organs and brain. --Steroids. They’ve caused global scandals. They’re banned in most athletic competitions. Yet the same properties that help elite athletes and bodybuilders improve performance also make steroids valuable for treating many illnesses and injuries, such as AIDS and cancer. So if steroids a...

How can we use statistics to evaluate risk? Dig into the difference between relative risk and absolute risk and how each is used in the news.--A new drug reduces the risk of heart attacks by 40%. Shark attacks are up by a factor of two. Drinking a liter of soda per day doubles your chance of developing cancer. These are all examples of a common way risk is presented in news articles, and can often...

Explore the essential role vultures play in cleaning our ecosystems and why their conservation is key to a healthy planet.--In the African grasslands, a gazelle suffering from tuberculosis takes its last breath. The animal’s corpse threatens to infect the water, but for the vulture, this isn’t a problem: it’s a feast. With a stomach of steel that can digest diseased meat and waste, vultures are es...

View full lesson: http://ed.ted.com/lessons/grammar-s-great-divide-the-oxford-comma-ted-edIf you read "Bob, a DJ and a clown" on a guest list, are three people coming to the party, or only one? That depends on whether you're for or against the Oxford comma -- perhaps the most hotly contested punctuation mark of all time. When do we use one? Can it really be optional, or is there a universal rule?...

Why do medical implants like insulin pumps and prosthetic knees need replacement? Explore how the immune system fights implants and how new devices are trying to help. --Insulin pumps improve the lives of millions of people with diabetes around the world by monitoring blood sugar, delivering insulin, and preventing the need for constant finger-pricking. But there’s a catch: they’re temporary. And...

What controls aging? Biochemist Cynthia Kenyon has found a simple genetic mutation that can double the lifespan of a simple worm, C. elegans. The lessons from that discovery, and others, are pointing to how we might one day significantly extend youthful human life. Talk by Cynthia Kenyon. Learn more about your ad choices. Visit megaphone.fm/adchoices

View full lesson: http://ed.ted.com/lessons/from-the-top-of-the-food-chain-down-rewilding-our-world-george-monbiot Our planet was once populated by megafauna, big top-of-the-food-chain predators that played their part in balancing our ecosystems. When those megafauna disappear, the result is a "trophic cascade," where every part of the ecosystem reacts to the loss. How can we stay in balance? Geor...

View full lesson: http://ed.ted.com/lessons/jonathan-driori-the-beautiful-tricks-of-flowersIn this visually dazzling talk, Jonathan Drori shows the extraordinary ways flowering plants -- over a quarter million species -- have evolved to attract insects to spread their pollen: growing 'landing-strips' to guide the insects in, shining in ultraviolet, building elaborate traps, and even mimicking othe...

The adventure continues! Episode 7: Ethic and Hedge find themselves in a massive tower. Can they make it past the energy streams to reach the Node of Creation? --This is episode 7 of our animated series “Think Like A Coder.” This 10-episode narrative follows a girl, Ethic, and her robot companion, Hedge, as they attempt to save the world. The two embark on a quest to collect three artifacts and mu...

What makes crystals grow into their signature shapes? Dig into the atomic patterns and unique properties of crystals. --Many crystals have signature shapes— like the cascade of pointed quartz or a pile of galena cubes. Every crystal’s atoms have a defining feature: their organized, repeating pattern. The pattern isn't restricted to minerals- sand, ice, metals and DNA also have crystalline structur...

Dive into the Egyptian myth of Isis, a powerful goddess protecting her son from her murderous brother with the help of seven scorpions. --A woman in rags emerged from a swamp flanked by seven giant scorpions and approached a magnificent mansion to beg for food. But the mistress of the house took one look at her grimy clothes and unusual companions and slammed the door in her face. Little did the m...

Travel into the brain to see how its network of neurons transmit your thoughts and what factors determine how quickly you think.--Your mortal enemy has captured you and hooked you up to a bizarre experiment. He’s extended your nervous system with one very long neuron to a target about 70 meters away. At some point, he’s going to fire an arrow. If you can then think a thought to the target before t...

Ancient monuments give us clues to astonishing past civilizations -- but they're under threat from pollution, war, neglect. Ben Kacyra, who invented a groundbreaking 3D scanning system, is using his invention to scan and preserve the world's heritage in archival detail. (Watch to the end for a little demo.) Talk by Ben Kacyra. Learn more about your ad choices. Visit megaphone.fm/adchoices