The Infinite Hotel Paradox - Jeff Dekofsky
The Infinite Hotel Paradox - Jeff Dekofsky
The Infinite Hotel Paradox - Jeff Dekofsky

The Infinite Hotel Paradox - Jeff Dekofsky - TED-Ed

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The Infinite Hotel, a thought experiment created by German mathematician David Hilbert, is a hotel with an infinite number of rooms. Easy to comprehend, right?  Wrong. What if it's completely booked but one person wants to check in? What about 40? Or an infinitely full bus of people? Jeff Dekofsky solves these heady lodging issues using Hilbert's paradox.

Lesson by Jeff Dekofsky, animation by The Moving Company Animation Studio.

Can you solve the three gods riddle? - Alex Gendler

View full lesson: You and your team have crash-landed on an ancient planet. Can you appease the three alien overlords who rule it and get your team safely home? Created by logician Raymond Smullyan, and popularized by his colleague George Boolos, this riddle has been called the hardest logic puzzle ever. Alex Gendler shows how to solve it. Lesson by Alex Gendler, animation by Artrake Studio.

How Folding Paper Can Get You to the Moon

Can folding a piece of paper 45 times get you to the moon? By seeing what happens when folding just one piece of paper, we see the unbelievable potential of exponential growth. This lesson will leave you wanting to grab a piece of paper to see how many times you can fold it! Lesson by Adrian Paenza, animation by TED-Ed.

Questions No One Knows the Answers to (Full Version)

In the first of a new TED-Ed series designed to catalyze curiosity, TED Curator Chris Anderson shares his boyhood obsession with quirky questions that seem to have no answers. (Introducing the series "Questions no one knows the answers to") "Questions No One Knows the Answers to" was animated by Andrew Park (

Can you solve the egg drop riddle? - Yossi Elran

Check out our Patreon page: View full lesson: The city has just opened its one-of-a-kind Faberge Egg Museum, with a single egg displayed on each floor of a 100-story building -- and the world’s most notorious jewel thief already has her eyes on the prize. Can you help the thief formulate a plan that will drop the most expensive egg she can get safely into her waiting truck? Yossi Elran shows how. Lesson by Yossi Elran, directed by Artrake Studio. Thank you so much to our patrons for your support! Without you this video would not be possible! Yuh Saito, Sarabeth...

Why don't perpetual motion machines ever work? - Netta Schramm

View full lesson: Perpetual motion machines — devices that can do work indefinitely without any external energy source — have captured many inventors’ imaginations because they could totally transform our relationship with energy. There’s just one problem: they don’t work. Why not? Netta Schramm describes the pitfalls of perpetual motion machines. Lesson by Netta Schramm, animation by TED-Ed.

Why Photos of the Eiffel Tower at Night are Illegal

Build your website for 10% off at Get a Half as Interesting t-shirt: Suggest a video and get a free t-shirt if we use it: Follow Half as Interesting on Twitter: Discuss this video on Reddit: Check out my podcast with Brian from Real Engineering: (iTunes link) (YouTube link) Check out my other channel:

How to unboil an egg - Eleanor Nelsen

View full lesson: It’s so obvious that it’s practically proverbial: you can’t unboil an egg. But actually, it turns out that you can -- sort of. Eleanor Nelsen explains the process by which mechanical energy can undo what thermal energy has done. Lesson by Eleanor Nelsen, animation by Provincia Studio.

Can you solve the locker riddle? - Lisa Winer

View full lesson: Your rich, eccentric uncle just passed away, and you and your 99 nasty relatives have been invited to the reading of his will. He wanted to leave all of his money to you, but he knew that if he did, your relatives would pester you forever. Can you solve the riddle he left for you and get the inheritance? Lisa Winer shows how. Lesson by Lisa Winer, animation by Artrake Studio.

Only a Schizophrenic or a Genius Can Answer This

Many psychiatric tests and methods are used in order to find out what is going on in the patient’s head. Here are two simple questions that can be answered only by a person with schizophrenia or by an extraordinary genius person. Subscribe to Bright Side : ---------------------------------------------------------------------------------------- Our Social Media: Facebook: Instagram: 5-Minute Crafts Youtube:  ---------------------------------------------------------------------------------------- For more videos and articles visit:

The Banach–Tarski Paradox

Q: "What's an anagram of Banach-Tarski?" A: "Banach-Tarski Banach-Tarski." twitter: Instagram: Kevin’s Field Day video: Field Day: Deep dream animation by If you like it, you'll love this video also by Nader: Chocolate illusion: Chocolate illusion video: related Numberphile videos: sizes of infinity (includes diagonal argument): infinity paradoxes: Vi Hart on types of infinity: Countable & uncountable definitions: Banach-Tarski on wikipedia: Banach-Tarski proofs: Banach-Tarski explinations online: Cayley graph animated gif: Hilbert’s hotel on wikipedia: types of infinity: set theory and quantum physics: LHC gif: Zermelo-Fraenkel axioms of mathematics: Is math invented or discovered? more deep dream images: BOOKS: The Pea and the Sun: The Outer Limits...

Can you solve the bridge riddle? - Alex Gendler

View full lesson: Taking that internship in a remote mountain lab might not have been the best idea. Pulling that lever with the skull symbol just to see what it did probably wasn’t so smart either. But now is not the time for regrets because you need to get away from these mutant Can you use math to get you and your friends over the bridge before the zombies arrive? Alex Gendler shows how. Lesson by Alex Gendler, animation by Artrake Studio.

Just How Small is an Atom?

Just how small are atoms? And what's inside them? The answers turn out to be astounding, even for those who think they know. This fast-paced animation uses spectacular metaphors (imagine a blueberry the size of a football stadium!) to give a visceral sense of the building blocks that make our world. Lesson by Jonathan Bergmann, animation by Cognitive Media.

Can you solve the virus riddle? - Lisa Winer

View full lesson: Your research team has found a prehistoric virus preserved in the permafrost and isolated it for study. After a late night working, you’re just closing up the lab when a sudden earthquake hits and breaks all the sample vials. Will you be able to destroy the virus before the vents open and unleash a deadly airborne plague? Lisa Winer shows how. Lesson by Lisa Winer, animation by Artrake Studio.

Can you solve "Einstein’s Riddle"? - Dan Van der Vieren

View full lesson: View all the clues here: Before he turned physics upside down, a young Albert Einstein supposedly showed off his genius by devising a complex riddle involving a stolen exotic fish and a long list of suspects. Can you resist tackling a brain teaser written by one of the smartest people in history? Dan Van der Vieren shows how. Lesson by Dan Van der Vieren, animation by Artrake Studio.

Would you sacrifice one person to save five? - Eleanor Nelsen

View full lesson: Imagine you’re watching a runaway trolley barreling down the tracks, straight towards five workers. You happen to be standing next to a switch that will divert the trolley onto a second track. Here’s the problem: that track has a worker on it, too — but just one. What do you do? Do you sacrifice one person to save five? Eleanor Nelsen details the ethical dilemma that is the trolley problem. Lesson by Eleanor Nelsen, animation by Eoin Duffy.

Can you solve the pirate riddle? - Alex Gendler

View full lesson: It’s a good day to be a pirate. Amaro and his four mateys – Bart, Charlotte, Daniel, and Eliza have struck gold – a chest with 100 coins. But now, they must divvy up the booty according to the pirate code — and pirate code is notoriously complicated. Can you help come up with the distribution that Amaro should propose to make sure he lives to tell the tale? Alex Gendler shows how. Lesson by Alex Gendler, animation by Artrake Studio.

History’s deadliest colors - J. V. Maranto

View full lesson: When radium was first discovered, its luminous green color inspired people to add it into beauty products and jewelry. It wasn’t until much later that we realized that radium’s harmful effects outweighed its visual benefits. Unfortunately, radium isn’t the only pigment that historically seemed harmless or useful but turned out to be deadly. J. V. Maranto details history’s deadliest colors. Lesson by J. V. Maranto, animation by Juan M. Urbina.

What a MILLION Dollars Gets You Around the World

What could you buy with $1,000,000 around the world? Which places are far cheaper than the others? Today we'll take a look at What a Million Dollars Gets You Around the World⭐ SUBSCRIBE: ⭐ WEBSITE (You can suggest a topic): SUPPORT US: Patreon.......► CHAT: DISCORD.....► SOCIAL: Facebook...► Instagram..► Twitter........► Subreddit...► -------------------------------------------------------------------------- Sources for this episode:

What is Zeno's Dichotomy Paradox? - Colm Kelleher

View full lesson: Can you ever travel from one place to another? Ancient Greek philosopher Zeno of Elea gave a convincing argument that all motion is impossible - but where's the flaw in his logic? Colm Kelleher illustrates how to resolve Zeno's Dichotomy Paradox. Lesson by Colm Kelleher, animation by Buzzco Associates, inc.

The rise and fall of the Berlin Wall - Konrad H. Jarausch

Check out our Patreon page: View full lesson: On August 13, 1961, construction workers began tearing up streets and erecting barriers in Berlin. This night marked the beginning of one of history’s most infamous dividing lines: the Berlin Wall. Construction continued for a decade as the wall cut through neighborhoods, separated families, and divided not just Germany, but the world. Konrad H. Jarausch details the history of the Berlin Wall. Lesson by Konrad H. Jarausch, directed by Remus & Kiki.

The myth of Prometheus - Iseult Gillespie

Check out our Patreon page: View full lesson: Before the creation of humanity, the Greek gods won a great battle against a race of giants called the Titans. Most Titans were destroyed or driven to the eternal hell of Tartarus. But the Titan Prometheus, whose name means foresight, persuaded his brother Epimetheus to fight with him on the side of the Gods. Iseult Gillespie shares the myth of Prometheus. Lesson by Iseult Gillespie, directed by Léa Krawczyk. Thank you so much to our patrons for your support! Without you this video would not be possible. Yalda A., Susan Herder, Andrew Bosco, Craig Sheldon,...

Why incompetent people think they're amazing - David Dunning

Check out our Patreon page: View full lesson: How good are you with money? What about reading people’s emotions? How healthy are you, compared to other people you know? Knowing how our skills stack up against others is useful in many ways. But psychological research suggests that we’re not very good at evaluating ourselves accurately. In fact, we frequently overestimate our own abilities. David Dunning describes the Dunning-Kruger effect. Lesson by David Dunning, directed by Wednesday Studio, music and sound by Tom Drew. Thank you so much to our patrons for your support! Without you this video would not be...

Simpson's Paradox

Thanks to for sponsoring this video! This video is about Simpson's paradox, a statistical paradox and ecological fallacy where seemingly contradictory results are implied by a single set of data depending on how it's grouped. The paradox can arise in medical studies, student test scores, and so on. Support MinutePhysics on Patreon! Link to Patreon Supporters: REFERENCES: Interactive Simpson’s Paradox Explainer: Wisconsin vs Texas schools: Detailed analysis of Wisconsin vs Texas schools: National US Standardized Test Data:,20113,20093-SRPUV-SDRACE-NP,AL,AK,AZ,AR,CA,CO,CT,DE,DC,FL,GA,HI,ID,IL,IN,IA,KS,KY,LA,ME,MD,MA,MI,MN,MS,MO,MT,NE,NV,NH,NJ,NM,NY,NC,ND,OH,OK,OR,PA,RI,SC,SD,TN,TX,UT,VT,VA,WA,WV,WI,WY,DS-MN_MN-Y_J-0-0-5 MinutePhysics is on twitter - @minutephysics And facebook - And Google+ (does anyone use this any more?) - Minute Physics provides an energetic and entertaining view of...

Can you solve the temple riddle? - Dennis E. Shasha

View full lesson: Your expedition finally stands at the heart of the ancient temple. But as you study the inscriptions in the darkness, two wisps of green smoke burst forth. The walls begin to shake. The giant sandglass begins flowing with less than an hour before it empties, and a rumbling tells you that you don’t want to be around when that happens. Can you use math to escape the temple? Dennis E. Shasha shows how. Lesson by Dennis E. Shasha, animation by Artrake Studio.