Why Do Escalator Steps Have Teeth?

The surprising science of escalators. Sponsored by Brilliant - check out https://brilliant.org/veritasium to start learning for free. Plus, our viewers get 20% off an annual Premium subscription for unlimited daily access to all Brilliant courses. If you’re looking for a molecular modelling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ A massive thank you to Emily Zhang for suggesting this idea and helping shape it. A huge thanks to the team at OTIS, especially Ed Jacovino, Gregory Sefcik and Dirk Winkelhake, for their time and expertise. Thank you also to Professor Gero Gschwendtner, Professor Michael Fu, and Dr. Peter Kauffmann for all their help on the project. ▀▀▀ 0:00 When escalators go wrong 2:43 The first escalator 5:01 How does an escalator work? 8:35 Why do escalators have grooves? 10:05 Why do escalators have brushes? 10:21 The hand rail moves faster than the steps 12:05 You generate electricity on escalators 14:09 How does an escalator break? 18:47 How safe are escalators really? ▀▀▀ References: https://ve42.co/EscalatorRefs Images & Video: https://ve42.co/EscalatorImgRefs ▀▀▀ Special thanks to our Patreon supporters: Alex Porter, Alexander Tamas, Anton Ragin, Anupam Banerjee, Gnare, Ibby Hadeed, Jon Jamison, Juan Benet, Lee Redden, Meekay, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Ubiquity Ventures, Adam Foreman, Albert Wenger, armedtoe, Balkrishna Heroor, Bertrand Serlet, Blake Byers, Bruce, Dave Kircher, David Johnston, David Tseng, Evgeny Skvortsov, Garrett Mueller, gpoly, Jeromy Johnson, JT, Justin Waters, KeyWestr, Kyi, Marinus Kuivenhoven, Matthias Wrobel, meg noah, Michael Bush, Michael Krugman, Robert Oliveira, Tj Steyn, wolfee. ▀▀▀ Writers - Darius Garewal, Casper Mebius, Emily Zhang & Derek Muller Presenters - Derek Muller & Latif Nasser Producer & Director - Darius Garewal Editor - Spencer Wright Camera Operators - Derek Muller, Darius Garewal & Gre