Alzheimer’s disease is the most common cause of dementia, affecting over 40 million people worldwide. And though it was discovered over a century ago, scientists are still grappling for a cure. Ivan Seah Yu Jun describes how Alzheimer’s affects the brain, shedding light on the different stages of this complicated, destructive disease.
When you look at a blank computer screen, do you ever see little things moving across your field of vision?
The facts behind floaters:
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.
If you have a tattoo, you’re part of a rich cultural history that dates back at least 8,000 years. Where did this practice of body modification come from, and how has its function changed over time? Addison Anderson tracks the history of getting inked.
Enjoy!
Huumans have marked their bodies with tattoos for thousands of years. These permanent designs—sometimes plain, sometimes elaborate, always personal—have served as amulets, status symbols, declarations of love, signs of religious beliefs, adornments and even forms of punishment. Joann Fletcher, research fellow in the department of archaeology at the University of York in Britain, describes the history of tattoos and their cultural significance to people around the world, from the famous ” Iceman,” a 5,200-year-old frozen mummy, to today’s Maori.
You learn something new everyday!
Ever go to pour ketchup on your fries…and nothing comes out? Or the opposite happens, and your plate is suddenly swimming in a sea of red? George Zaidan describes the physics behind this frustrating phenomenon, explaining how ketchup and other non-Newtonian fluids can suddenly transition from solid to liquid and back again.
TED-Ed educator Nathan S. Jacob explains how optical illusions manage to trick our brains into thinking we’re seeing something we’re actually not.
Optical illusions are images that seem to trick our minds into seeing something different from what they actually are. But how do they work? Nathan S. Jacobs walks us through a few common optical illusions and explains what these tricks of the eye can tell us about how our brains assemble visual information into the 3D world we see around us.