*Watch with headphones on! Is 45 minutes really the longest anyone can stay in a perfectly silent, pitch-black room? Support Veritasium on Patreon Check out Audible: Want to watch the whole hour of silence? Many stories have circulated claiming the longest anyone has stayed in an ultra-quiet anechoic chamber is 45 minutes, the reason being any longer would drive you insane. To me this sounded like unsubstantiated rubbish, like the claim the Great Wall is the only manmade structure visible from space. So I put my own psyche on the line, subjecting myself to over an hour of the most intense quiet on Earth. No, this was not THE quietest room on Earth (-9dB) but it is one of the quietest, and the truth is once you put a person inside, they are by far the loudest thing in there so the sound rating of the room is irrelevant.
I was not surprised to find that I could stay in there for as long as I liked and feel perfectly fine. What was surprising is that my heartbeat was audible. You can hear it on the sound recording. Now I wasn't consciously aware of the sound of my heart while in the room, but I was more aware of the feeling of it beating.
Huge thank you to everyone at BYU: Duane Merrell, Spencer Perry, Cameron Vongsawad, Jazz Myers, Ann Clawson, and Robert Willes.
Follow Michael Stevens Tell Geek and Sundry that Vsauce says "hi! " and SUB: music courtesy of Thanks to: and For helping me with this video at Summer in the City! theINENIvlogs behind the scenes Summer in the City vid with me: Why videos views freeze in the 300s on YouTube (sub to this channel FTW, seriously): Japan Earthquake and Earth's rotation: All people in one place LIVING: shoulder-to-shoulder: BBC Jump Video: SCALE OF UNIVERSE AWESOME: STRAIGHTDOPE article on a jump: Dot Physics on the jump: Interactive scale of the universe: Decimate: Dunbar's Number: NPR story on Dunbar's number: Life Expectency: How many people you meet in your life: Newton's Third Law. If you're a true genius, you'll easily solve these 24 picture riddles, logic puzzles, trivia and fun quiz questions. The last tricky riddles is only for the smartest people! TELL your answers IN THE COMMENTS to the last brain teaser and tell us how many of these you managed to answer right: ) Subscribe to 7-Second Riddles: - Join us on Social Media: Facebook: Instagram: -.
Click this link to subscribe to Vsauce for more! It's FREE! Michael Stevens on Twitter: Jake's channel: Pizza trails: and frog horse: Food patterns: Cool submission on color visio and real vs. "fake" color: How LCD screens show color: Best LCD explanation video on YouTube (sub to this guy ftw): Electric vs Process yellow: Cone cells: Lemon battery: Electricity from apples ART: Apple LED VIDEO: Steven Shaheen light bulb people: Merve Kahraman's revitalizer wax lamp: Fukusada wodden light bulb: Tang Yau Hoong: Frame climbing wall: Minimal LEGO art: couple and hidden baby: Zebras and lions: clever billboard ad: xkcd "When Will We Forget? " Year book face: tesselation: *BONUS* crayon pixel art. The world's roundest object helps solve the longest running problem in measurement - how to define the kilogram. Support Veritasium on Patreon: A kilogram isn't what it used to be. Literally. The original name for it was the 'grave', proposed in 1793 but it fell victim to the French Revolution like its creator, Lavoisier. So begins the tale of the most unusual SI unit. The kilogram is the only base unit with a prefix in its name, and the only one still defined by a physical artifact, the international prototype kilogram or IPK. But the problem with this definition has long been apparent. The IPK doesn't seem to maintain its mass compared to 40 similar cylinders minted at the same time. The goal is therefore to eliminate the kilogram's dependence on a physical object. Two main approaches are being considered to achieve this end: the Avogadro Project and the Watt Balance. The Avogadro project aims to redefine Avogadro's constant (currently defined by the kilogram - the number of atoms in 12 g of carbon-12) and reverse the relationship so that the kilogram is precisely specified by Avogadro's constant. This method required creating the most perfect sphere on Earth. It is made out of a single crystal of silicon 28 atoms. By carefully measuring the diameter, the volume can be precisely specified. Since the atom spacing of silicon is well known, the number of atoms in a sphere can be accurately calculated. This allows for a very precise determination of Avogadro's constant. Special thanks to Katie Green, Dr. David Farrant, the CSIRO, and the National Measurment Institute for their help. Thanks also to Nessy Hill for filming and reviewing earlier drafts of this video. There is debate as to whether this is truly the roundest object ever created. The Gravity Probe-B rotors are also spherical with very low tolerances such that they may in fact be rounder. Music by Kevin McLeod (incompetech) Decision, Danse Macabre, Scissors.