View full lesson- http-//ed.ted.com/lessons/why-do-we-itch-emma-bryce The average person experiences dozens of individual itches each day. We've all experienced the annoyance of an inconvenient itch -- but have you ever pondered why we itch in the first place? Is there actually an evolutionary purpose to the itch, or is it simply there to annoy us? Emma Bryce digs deep into the skin to find out. Lesson by Emma Bryce, animation by Sashko Danylenko.

Sign up for our newsletter and never miss an animation- http-//bit.ly/TEDEdNewsletter Sometimes, against a uniform, bright background such as a clear sky or a blank computer screen, you might see things floating across your field of vision. What are these moving objects, and how are you seeing them? Michael Mauser explains the visual phenomenon that is floaters. Lesson by Michael Mauser, animation by Reflective Films.

View full lesson- http-//ed.ted.com/lessons/the-science-of-spiciness-rose-eveleth When you take a bite of a hot pepper, your body reacts as if your mouth is on fire -- because that's essentially what you've told your brain! Rose Eveleth details the science and history behind spicy foods, giving insights into why some people continue to pay the painful price for a little spice. Lesson by Rose Eveleth, animation by Flaming Medusa Studios Inc.

View full lesson- http-//ed.ted.com/lessons/how-does-your-brain-respond-to-pain-karen-d-davis Ouch! 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 Brett Underhill.

View full lesson- http-//ed.ted.com/lessons/how-do-we-smell-rose-eveleth An adult human can distinguish up to 10,000 odors. You use your nose to figure out what to eat, what to buy and even when it's time to take a shower. But how do the molecules in the air get translated into smells in your brain? Rose Eveleth charts the smelly journey through your olfactory epithelium and explains why scent can be so subjective. Lesson by Rose Eveleth, animation by Igor Coric.

View full lesson- http-//ed.ted.com/lessons/eye-vs-camera-michael-mauser Your eyes don't always capture the world exactly as a video camera would. But the eyes are remarkably efficient organs, the result of hundreds of millions of years of coevolution with our brains. Michael Mauser outlines the similarities and differences between your eye and a video camera. Lesson by Michael Mauser, animation by Nick Hilditch.

View full lesson- http-//ed.ted.com/lessons/how-we-see-color-colm-kelleher There are three types of color receptors in your eye- red, green and blue. But how do we see the amazing kaleidoscope of other colors that make up our world? Colm Kelleher explains how humans can see everything from auburn to aquamarine. Talk by Colm Kelleher, animation by TED-Ed.

View full lesson- http-//ed.ted.com/lessons/how-to-master-your-sense-of-smell-alexandra-horowitz Some perfumers can distinguish individual odors in a fragrance made of hundreds of scents; tea-experts have been known to sniff out the exact location of a particular tea; and the NYC Transit Authority once had a employee responsible only for sniffing out gas leaks. But can anyone learn to smell with the sensitivity of those experts? Alexandra Horowitz shares three simple steps to a better nose. Lesson by Alexandra Horowitz, animation by Black Powder Design.

Check out our Patreon page- https-//www.patreon.com/teded View full lesson- https-//ed.ted.com/lessons/the-science-of-hearing-douglas-l-oliver The ability to recognize sounds and identify their location is possible thanks to the auditory system. That's comprised of two main parts- the ear, and the brain. The ear's task is to convert sound energy into neural signals; the brain's is to receive and process the information those signals contain. To understand how that works, Douglas L. Oliver follows a sound on its journey into the ear. Lesson by Douglas L. Oliver, animation by Cabong Studios. Thank you so much to our patrons for your support! Without you this video would not be possible! Irindany Sandoval, William Bravante, Elizabeth Parker, Sai Krishna Koyoda, Therapist Gus, Samuel Barbas, Betsy Feathers, Maxwell Ingram, Ajinkya Deshmukh, Victoria Soler-Roig, Abdulmateen Aderinto, Pavel Maksimov, Barbara Younker, Cyrus Garay, Yvette Mocete, Mike Azarkman, Valeria Sloan Vasquez, Patricia Alves Panagides, William Biersdorf, Michael Aquilina, Vinamr L. Sachdeva, FireWolfLasers, Kshitij Shah, Mohammad Said, Teach Me Dine - Navajo Language, Victoria Veretilo, Rebecca Reineke, Felipe Hoff, Kyanta Yap, Brandon Thomas, Lewis Westbury, Ojas Kapoor, Johnny Gutierrez, Mirzat Turap, Jaime Arriola, Emilia Alvarado, Javid Gozalov, Zhen You Liu , Ethan , Philipp Hiestand, Paul Beard, Deepak Iyer, Markus Goldhacker, Mihai Sandu, Keven Webb, Hendrik Mueller, Maurice Castonguay, Kristiyan Bonev, Maryam Dadkhah, and Joshua Wasniewski.

Download a free audiobook version of "Hallucinations" and support TED-Ed's nonprofit mission- https-//adbl.co/2Kpt43k Check out our full book recommendation- https-//shop.ed.ted.com/products/hallucinations View full lesson- https-//ed.ted.com/lessons/what-causes-hallucinations-elizabeth-cox A condition called Charles Bonnet Syndrome can cause blind patients to hallucinate scenes in vivid color. fMRI studies show that these hallucinations activate the same brain areas as sight -- areas that are not activated by imagination. Other hallucinations also involve the same brain areas as real sensory experiences. What's going on? Elizabeth Cox details the science of hallucinations. Lesson by Elizabeth Cox, directed by Nerdo. Thank you so much to our patrons for supporting us on Patreon! Without you this video would not be possible! Mayra Urbano, Kostadin Mandulov, Alex Schenkman, Sdiep Sriram, Ivan Todorovic, Antero Semi, Yanuar Ashari, Mrinalini, Anthony Kudolo, Querida Owens, Hazel Lam, Manav parmar, Dwight Tevuk, Stephen A. Wilson, Siamak H, Dominik Kugelmann, Katie Winchester, David Rosario, Samuel Doerle, Be Owusu, Susan Herder, Savannah Scheelings, Prasanth Mathialagan, Yanira Santamaria, Chad Harper, Dawn Jordan, Chris Mathew, Constantin Salagor, Activated Classroom Teaching, Kevin Wong, Umar Farooq, Goh Xiang Ting Diana, Dmitry Neverov, Tushar Sharma, Cristobal Medina Moenne, Silas Schwarz, MJ Tan Mingjie, Yansong Li, Henry Li, Kyle Nguyen, Taylor Hunter, Noa Shore, Lex Azevedo, Merit Gamertsfelder, Bev Millar, Jhuval , SookKwan Loong, Daniel Day, Rodrigo Carballo, Marc Veale, Boytsov Ilya, Bozhidar Karaargirov, and ilya bondarik.