Liquid Sand Hot Tub- Fluidized air bed

Liquid Sand Hot Tub- Fluidized air bed


I’m sitting in a hot tub filled to the brim with solid sand. (laughter) This is one of the coolest things ever! If you take a tub of sand like this and then add air in JUST the right way, it basically becomes a liquefied soup. (music) In science, this is known as a fluidized bed. It’s used in industrial applications such as powder coat painting or in grain silos to make sure that the grain flows smoothly to the outlet. (music) With air on the top surface is nearly frictionless. It’s like an air hockey table. (music continues) And then when you cut off the air, it freezes everything exactly where it’s at. (music continues) So, today I’m going to show you how to make a simple version like this yourself. And then because I became curious what it would feel like to be fully immersed in something like this… We made a hot tub sized version. As you can see from the sixty-year-old video from the Royal Institute of Science, this demo isn’t exactly new. I’ve wanted to build one for a long time, But you can find literally NO information online on how to make one like that. So I started combing through a bunch of patent drawings for massive industrial sized fluid beds, And I noticed that instead of one big inlet, they all had a bunch of small holes to deliver the air. So starting with that in mind, it still took us 25 failed versions before we arrived at this design. As you can see it’s just a bunch of half-inch PVC pipes arranged sort of in a ladder. But the key is to drill two 1 millimeter holes 90 degrees apart from each other and then do a bunch of those spaced to 25 millimeters apart. Then you glue all the pipes together, and just make sure you orient the holes down so that will keep the sand from getting in. And then you just seal off the container with some hot glue. And then fill your container with either fine sand or we found glass beads worked really well. And you can power with a small air compressor like this, or you could just rent a large nitrogen container like this for about 30 bucks, and that’ll give ten minutes of run time. As usual, I will put a link to all of the parts I used the build in the video description. So my buddy Ken can had an old broken Spa on his backyard which we decided to put to good use. (music) (laughter) It just stops, and you’re like locked in place. It’s like a weighted blanket on every surface of your body. (laughter) Ahhh! (music) Now that it was tested and ready, in my ongoing quest to be the favorite uncle… pew pew pew pew, Ahhh!, (screaming) I decided to surprise my nephews with it. (fizzing noise) woah, WOAH! AHHHHHHHHH! (laughter) (music) (laughter and screaming) But before we get to swimming in sand, let’s talk about the science behind a fluidized bed. Wait wait, don’t click away if you think science is boring. If you’re new here, You should know that my approach to science is similar to velociraptor hunting patterns. I try to bring people in with a catchy thumbnail or a cool thing to see, and then when they least expect it… rawr… clever girl, velociraptor shrieks Admittedly, the analogy breaks down a little at the end, but if you promise to hang with me for the next two minutes, I promise to try and walk the delicate line between trying to make things simple to understand, without oversimplifying or being condescending. Fluidization is just when you have enough upward air so that the force of the air pushing on each grain of sand is equal to the downward force of gravity or weight. And when that happens on any individual grain of sand, it hovers in equilibrium like this. You can think of forces acting on an object like a tug of war. If an object is in equilibrium, That means there’s a tie, and it doesn’t accelerate in either direction, just like in a real tug of war if the sides are even. However, if you add Stone Cold Steve Austin to this side that will make it totally unbalanced and will start to move this way, Which is actually what happens if you accidentally turn the air up too high. As a fluidization occurs in that sweet spot where the sand particles hover in equilibrium, Which makes them easy to move around. This is also the reason sometimes you’ll see pools pumped with air to cushion the landing for the divers. Now you notice that some stuff floats in the sand and other stuff sinks. This has to do with the buoyancy force, which is a function of the density of the surrounding fluid and the volume of the object itself. Whenever an object exists in a pressure gradient, there are forces from pressure pushing in on all sides, but they push a little bit harder the deeper that you are. Which is why it hurts more to be the bottom guy in a dog pile, or it hurts your ears more the deeper you dive in the pool. And this makes sense because the deeper you dive the more water there is above you pushing down. And if you add up the size and direction of all those arrows, a bunch of stuff cancels out and you’re left with one net force pointing upwards. THAT is the buoyancy force. And if your buoyancy force happens to be greater than your force from gravity, you float. And if your buoyancy force happens to be less than the force from gravity, you sink. Now, we usually think of buoyancy with water, but you can think of things like helium balloons being buoyant in our atmosphere. So here’s a trick question: which of these has a higher buoyancy force? It’s actually… the rubber ball? Buoyancy force has nothing to do with the density of the object, just the volume. So since the rubber ball takes up more space, it has a higher buoyancy force. But, you might object then why does the rubber ball sink and the balloon floats? Remember, it’s a tug of war. The rubber ball sinks because the force from gravity on the thick rubber skin and the air inside, is bigger than the buoyancy force. But for the balloon, even though it doesn’t have as big of a buoyancy force compared to the ball, It still floats up, because that buoyancy force is bigger than the weight arrow from the helium and the thin rubber shell. And the helium will keep rising like a ball floating up from deep in a lake. And then it will eventually hang out where the density of the atmosphere is roughly equal to the density of the helium of the balloon, Because that’s where the tug-of-war becomes equal. Phew! We made it through! Now back to my nephews. (giggling) (screaming) (laughter) (screaming and laugher) Aw! No, oh no! I can’t get it out! Get it! (Nephew): I can’t! (Other Nephew): Got it! Turn it off! Ok, cut it! AH! (Laughter) Christmas is coming, and with the help of Casper who happened to support this video, I got your back. And with the exception of a Bob Ross chia pet, what could possibly be better than the gift of a good night’s rest? With Casper, you order online, and then they’ll ship it right to your door for free and it shows up in a box like this, And then you open it and it magically expands to actual mattress size! We totally love ours, and with over 20,000 reviews with an average rating of 4.8 stars on sites like Amazon, There’s a pretty good chance you’ll love it, too. And they’re also affordable because you cut out the sweaty price haggling commission based middleman who works at a typical mattress store. And you could try it out for a hundred days, and if at the end of that you’re like meh… They’ll come pick it up for FREE, you get all your money back, no questions asked. So, skip the crowded mall this year and finish your Christmas shopping right now by going to Casper.com/MarkRober and using promo code mark Rover for $50 off any mattress. Merry Christmas! And thanks for watching. (Epic Outro Music)

100 Comments

  • Renn Snnn

    September 4, 2019

    1:19 soccer ball was sick

    Reply
  • Shane Starrette

    September 4, 2019

    You’re a clever girl.

    Reply
  • Marine & Maroon

    September 4, 2019

    I designed one of these for my science fair after watching this, and I won!

    Reply
  • oKayMia T

    September 4, 2019

    These Sand montages are soothing

    Reply
  • ณัษฐกรณ์ คงหนู

    September 4, 2019

    Wow

    Reply
  • Melissa Mahealani Resgonia

    September 4, 2019

    This is more fun than nasa

    Reply
  • Ethan Liang

    September 4, 2019

    This video is old lol

    Reply
  • Evie Everything

    September 4, 2019

    Omg can you please be my sickens teacher even tho u said everything she did today you make it funnier so please

    Reply
  • Pro_ Drone61

    September 4, 2019

    Why is quick sand called quick sand if you sink slow?

    Reply
  • علي

    September 4, 2019

    looks like an easy way to bury a corpse

    Reply
  • Ntokozo Fakude

    September 4, 2019

    I wish I had an uncle this smart and fun!!😊😊

    Reply
  • Hunter Wittman

    September 4, 2019

    I wanna go in that

    Reply
  • ArnorAteBscotch

    September 4, 2019

    Can i be your nephew? 😂

    Reply
  • Billy Carlos

    September 4, 2019

    I guess we’re not gonna talk about the pigeon in the beginning of the video

    Reply
  • Uluthando Ngidi

    September 4, 2019

    love the remix of patta patta you put btw…. showing SA some love

    Reply
  • Timmy Girard

    September 4, 2019

    Replace the sand with shards of glass, and then throw your enemies into it 😀

    Reply
  • CK Lunzaga

    September 4, 2019

    I learn about on mark rober's channel whahahahahahah

    Reply
  • Night Bot

    September 4, 2019

    Imagine there being a huge billion dollar project where they do this on a beach

    Reply
  • hope7096

    September 4, 2019

    1:34 RAINBOW

    Reply
  • ThePieGuy

    September 5, 2019

    I’m curious on why it only works on sand, if you know, please reply

    Reply
  • R.I.P Thirst

    September 5, 2019

    Imagine all the sand in there hair after lol 😂😂😂😂😂😂😂🤣🤣🤣😅😅😅

    Reply
  • MR MOOSE Sub to PEWDIEPIE

    September 5, 2019

    Thats amazing

    Reply
  • Nubbular Gaming

    September 5, 2019

    I really didn’t know that you could make a rainbow with sand. That’s really cool!

    Reply
  • Aj Rodriguez

    September 5, 2019

    Thanks to me we won the tug of war and THATS THE BOTTOM LINE CAUSE STONE COLD SAID SO!!!!!

    Reply
  • Jay Oliver

    September 5, 2019

    What was the nephew song

    Reply
  • Ying Ying Pls sub!

    September 5, 2019

    Wow

    Reply
  • ام ارين

    September 5, 2019

    I want to be his younger sister 😭😭

    Reply
  • Zachary Pittman

    September 5, 2019

    1:34 sand rainbow!!?

    Reply
  • Vivian Sotelo

    September 5, 2019

    Now this is Satisfying 👌🏼🤷🏼‍♀️

    Reply
  • All AboutButera

    September 5, 2019

    why do the balls have to be there

    Reply
  • Potato On Potato

    September 5, 2019

    Imagine all the sand in their cracks after

    Reply
  • Tori_Yt

    September 6, 2019

    Did anyone see the rainbow? <3

    Reply
  • Lauren Loves Life

    September 6, 2019

    my jaw has dropped

    Reply
  • alfredo Godoy

    September 6, 2019

    I wish u were my uncle

    Reply
  • Potatoman

    September 6, 2019

    I think some thing about science is really cool like the things you do

    Reply
  • Ajayhunter 25

    September 6, 2019

    is it possible to do it at a beach

    Reply
  • Jurassic kiju Shark

    September 6, 2019

    I think science is cool

    Reply
  • Ethan Bruce

    September 6, 2019

    He should drop a gopro in it lol

    Reply
  • Turtushig Ganbagana

    September 6, 2019

    1:34 why there is a rainbow ? it's a sand right ?

    Reply
  • Laura Liem

    September 6, 2019

    1:36 anyone see a rainbow? It's soo pretty
    / Like if u agree

    Reply
  • John Carlo Alsola

    September 6, 2019

    Woaahhhh

    Reply
  • bread

    September 6, 2019

    is it bad I could smell the sand?

    Reply
  • 0x0Athena0x0

    September 6, 2019

    If your nephew's don't realize they easily have the coolest uncle of all time, they are crazy!

    Reply
  • Gaming_matez 2000

    September 6, 2019

    Bruh, I’m only 11years old I don’t understand how you people do that OwO
    I wish I had an uncle that cared about meh TvT
    Oh well 😛

    Reply
  • Randomness Manor

    September 6, 2019

    Who needs school when we have you!!

    Only thing is….. you only upload once a month…..

    So SCHOOL IS NOW ONCE A MONTHS PEOPLES!!!!
    all students cheer as they have been released from torture

    Reply
  • Squigles_7

    September 6, 2019

    but soup is liquid dude

    Reply
  • ArabS0n

    September 6, 2019

    wtf

    Reply
  • Defaulty Yt

    September 6, 2019

    Soo Cool

    Reply
  • Main-Uddin Zisan

    September 7, 2019

    1:35
    That rainbow though.

    Reply
  • AKa5_ YT

    September 7, 2019

    5:08 I’m Caillou

    Reply
  • Elizabeth Villasenor

    September 7, 2019

    Keep it up man lov your videos

    Reply
  • johnny brandon

    September 7, 2019

    That is the coolest thing I've seen on YouTube. How scary if it was pool size and you went several ft. Below and the air shutoff. Instant burial. Scary.

    Reply
  • Slappy theSquirrel

    September 7, 2019

    Tell me that thumbnail doesnt look like a younger Adam Sandler…

    Reply
  • Jacob Lobraico

    September 7, 2019

    WHO LAUGHS LIKE THAT

    Reply
  • EMRIN NAZIF BIN AKMAL HAMDI -

    September 7, 2019

    This video turn out to be satisfying :/

    Reply
  • Atyaf Abdul

    September 7, 2019

    This sand is giving me a new level of anxiety.
    I feel like it will be in my hair, clothes. And under my nails 😖😖😖😣

    Reply
  • shivam singh

    September 7, 2019

    Mark, you're the best! 🙂

    Reply
  • Humza Abbasi

    September 7, 2019

    When you go under its a tad bit risky

    Reply
  • Licat Galsana

    September 7, 2019

    I still feel bad for the bird…

    Reply
  • Dale Thom

    September 7, 2019

    The possibilities to kill people in this is
    They swimming underneath?
    Turn the air off

    Reply
  • L Duncan

    September 7, 2019

    This is the true joy of learning and experimentation! God bless!

    Reply
  • Lifeishere 10CR7

    September 7, 2019

    Mark Rober: "In my ongoing quest to be the favorite uncle."
    Fatherhood: Am I a joke to you?

    Reply
  • TheDragonKing

    September 7, 2019

    I hate sand.It's coarse and rough and gets everywhere.

    Reply
  • Andaconda Nation

    September 7, 2019

    That’s awesome

    Reply
  • ket 223

    September 7, 2019

    Wow

    Reply
  • Lexi Radzieta

    September 7, 2019

    Who else saw the rainbow at 1:33 🌈

    Reply
  • legoy alex

    September 7, 2019

    this is like 3 years old

    Reply
  • Gx

    September 7, 2019

    Imagine having such an uncle😍😍

    Reply
  • Galaxy Lunna

    September 7, 2019

    WTF SO COOL

    Reply
  • Ocey Games

    September 7, 2019

    Make it a weapon when you hit some one it hardends on the and solidifies it so the get stuck

    Reply
  • TGC Fortnite Clan

    September 7, 2019

    3:11 quick sand

    Reply
  • Posing Zesty

    September 7, 2019

    Why are the kids wearing swimming pants when the pool has no liquid at all

    Reply
  • wilson s t

    September 7, 2019

    Genial esto sí es arenas movedizas

    Reply
  • Garrett McDuffee

    September 8, 2019

    I wish this dude was my uncle

    Reply
  • RiotRebirth

    September 8, 2019

    5:06 the left would definitely win cause Shaggy

    Reply
  • Choonghan Kok

    September 8, 2019

    Ask someone you hate very much to dive into it then stop the air

    Reply
  • MooMoo Space Cow

    September 8, 2019

    Wow wish i had a uncle like you

    Reply
  • melina cepeda

    September 8, 2019

    What if yoy dis this to a whole public beach like if you want them to do that

    Reply
  • Kenedi Campbell

    September 8, 2019

    Who else wanted to touch it so bad

    Reply
  • Ethan Tang

    September 8, 2019

    I love your channel! You make science so much fun to learn!

    A little backstory an me I HATE SCIENCE (well maybe I am just bad at it)

    thank you so much!

    Reply
  • David Eranosian

    September 8, 2019

    4:25 i loved that little bit. Lol.

    Reply
  • FredsucksatYT

    September 8, 2019

    8:12 what if they turned of the air lol

    Reply
  • benadryl horseflopper

    September 8, 2019

    I predict…..a mrbeast video titled last to leave liquid sand hot tub wins $10,000

    Reply
  • Matthias Berisiartua

    September 8, 2019

    Science or asmr

    Reply
  • Sparkle_Player

    September 8, 2019

    Who ever disliked just wished they could have this.

    Reply
  • Hanna Girma

    September 8, 2019

    Me (still) wondering if the birds ok.

    Reply
  • Hannah Jasal

    September 8, 2019

    Cool (θ‿θ)

    Reply
  • Candy Cosmetics

    September 8, 2019

    I learn more from you then I do from school 😂

    Reply
  • brokeboi099 233

    September 8, 2019

    I wish you were my uncle

    Reply
  • Josh Scott

    September 8, 2019

    Fill a pool

    Reply
  • Ordinary Sensei

    September 8, 2019

    This is why Youtube is the best online school

    Reply
  • Alexandria Long

    September 8, 2019

    Dude. Your videos are so interesting and fun while being extremely informative. I love them 😍 more please.

    Reply
  • Ordinary Sensei

    September 8, 2019

    This guy literally made his nephew eat sand or "drink" liquid sand 8:09 lmao

    Reply
  • Pro 7

    September 8, 2019

    This looks so fun

    Reply
  • crash02014

    September 9, 2019

    shaggy would still win the tug of war

    Reply
  • MoonlightStorm

    September 9, 2019

    I WANT ONE

    Reply
  • Jessica Johnson

    September 9, 2019

    😴😴😴😴😴😴

    Reply
  • Tyler Rooney

    September 9, 2019

    4:28 that should be your intro

    Reply
  • Alex_ Playz

    September 9, 2019

    MAGIC!!!

    Reply
  • Gabriele Rando

    September 9, 2019

    Imagine if while your under the electricity cuts off

    Reply

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