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Riding In a Hot Air Balloon Shaped Like a Pig… For SCIENCE


[MUSIC] This episode is sponsored by Dropbox [MUSIC] If it sometimes feels like the whole world
is pressing in on you, well that’s because it is.
A 1 square meter column of air above your head, stretching from here to the edge of
Earth’s atmosphere contains almost 10 tons of air. That’s a lot to carry on your
shoulders. But if it ever feels like too much, you know
what’s a great way to get away from it all? Balloons! That’s not what I meant guys. No, not like that, like this. [MUSIC] Balloons are magical.
Birds and planes stay aloft by using power to keep air moving over their wings [HELIUM VOICE]
We fill blimps and party balloons with lighter gases like helium.
But balloons like those weigh thousands of pounds, and they’re not filled with helium,
they’re filled with the very same air they’re floating in, yet they still go up.
Now that you mention it, why does the atmosphere itself stay up? That column of air above your head we talked
about earlier? It’s the same mass as a couple of elephants!
But just like elephants, air molecules obey gravity, and I don’t see any floating pachyderms
around. Think about it. Air is mostly empty space.
If I was an oxygen molecule, I’d have to travel the length of a football field on average
before I ran into another one. But occasionally, they do collide. Air molecules will fall until the collisions
bouncing them up, the pressure, is balanced by the weight pushing down on them.
Up high in the atmosphere, there’s not much air on top of us, and not much colliding going
on, so the pressure is pretty low. Down a little lower, we have a big mass of
air above squishing down, so things get a bit more crowded and the pressure is higher.
This sets up a gradient all the way down to Earth.
The lower we go, the air is more crowded, it takes more collisions to balance out that
squishing. Even though it’s mostly empty space, air
can still hold up a plane. I can sit in a chair, in the sky, riding on
almost nothing, and not fall to the ground. That is crazy. You may have heard that the Wright Brothers
are responsible for humans taking flight. But that’s wrong. 120 years before them,
in 1783, the Montgolfier brothers had the brilliant and kind of dangerous idea to light
a fire underneath a cloth b Heat ius what’s keeping this balloon up.
You’ve been told your whole life that hot air rises, but have you ever REALLY stopped
to ask yourself why? You know what? We’re gonna need a smaller balloon to figure that
one out. Ah, that’s better.
This is the ideal gas law, and it tells us pretty much everything we need to know about
how gases behave. Pressure is basically the force over a given
area on a surface. Whether a balloon inflates depends on the difference in pressure inside
and out. As we heat up air in a balloon, the molecules
gain kinetic energy and start colliding with more force on the inside surface. The pressure
goes up. As the balloon expands, that force is spread
across a larger surface area, which lowers the inner pressure. As we add heat, the volume
will go up up until the pressure on both sides is the same. Or until it pops. But this balloon isn’t made out of rubber.
It’s pretty rigid, once it fills up, it can’t really get bigger. But it does have
one thing that the rubber balloon doesn’t. A hole in the bottom. You know what the mass of air inside the balloon
envelope is? It’s 105,000 cubic feet. We can calculate that with a little bit of
math. It’s 105,000 cubic feet. I don’t know to be
honest. Well, I calculated it… When we first filled up this balloon on the
ground, it held about 3700 kg of air. Add in the basket, the fuel, the people, and of
course the balloon itself, and’s that’s another 500 kg or so. A lot of mass to lift. But then we added some… FIIIIIIIRE! [HEAVY METAL MUSIC] As we’re adding heat to this balloon, those
air molecules are moving around faster and faster, with more energy, and they’re pushing
on the balloon harder and harder, but the volume has remained the same, it hasn’t gotten
any bigger or smaller. The pressure is pretty much the same too, the balloon’s not collapsing
or popping. So that only leaves us with one other option,
there must be less air inside the balloon than when we were down on the ground. Hot
air has leaked out the bottom. We’re still being pulled down by gravity,
but the equal volume of cold air around us weighs more, and it’s falling down underneath
us. Balloons don’t defy gravity, they float because of gravity. Eureka! This is the principle of buoyancy
that Archimedes noticed when he saw his bathtub rise. It’s the reason that ships float,
because the weight they hold is less than the weight they displace, and the water falls
down around them. We know that buoyancy is due to gravity, because
bubbles rise here on Earth, and they don’t rise on the Space Station. You said that flying in a balloon is like
what? Flying in a hot air balloon is the closes
thing to being a cloud that I can think of. We’re just floating with the wind, as gentle
as can be. Flying in a hot air balloon kind of reminds
me that we have something in common with fish. We live in a fluid, it’s just that ours
is made of air instead of water. It’s kind of like floating on a bubble, and
that’s something that can lift all our spirits. Stay curious.

Yvette Parker

100 Comments

  1. Still blows my mind how much weight is above our heads as just air. What're the physics that it doesn't crush us?

  2. just here to make a single comment on 2:26 with three words:
    Alberto Santos Dumont

  3. 3:50 Let this be a lesson to all us smart people. When asking a "normal" person what the mass of something is just say "How heavy is it?". They may not know the answer but they will know what your talking about then.

  4. I hope you enjoyed my home town, Joe! We had great weather for you this year. Come back soon! (and stay curious! 😉 )

  5. I really wonder how is the target audience of this show? I makes me feel stupid watching it. reminds me of How to Basics Channel.

  6. i was always curious about how you navigate the balloon. don't you drift away due to winds? Is there a way to control the horizontal direction?

  7. I thought a boat on a balance beam versus the water it displaced would be even. The illustration at 5:13 has the weight of the displaced water being greater than the weight of the ship.

  8. A thing on my bucket list is going to hot air balloon ride. Unfortunately I'm also afraid of heights.

  9. My younger cousin still doesn't know how that much air could be above our heads without it killing us.

  10. Was one of the shots taken in Brazil?
    I guess now the world will know the terror of the Galinha Pintadinha Balloon

  11. In the comment section of the outdated video, I made a "nooo" comment on the words "oxygen molecule", and it can still be seen in the pastebin.
    However, my response to the replies confirming that O2 is indeed a molecule, got lost. I responded something along the lines of "I believe that it's called "dioxygen" because there are 2 oxygen atoms" (the atoms forming the dioxygen molecule).

    It was brave to edit a whole portion of the video for that mistake. I applaud you for that.

  12. Thumbs up! Another informative way to explain this would be to recast the ideal gas law in terms of density – i.e. pressure ~ density * temperature. An additional, interesting notation would be to explain the role of the decreasing ambient density & why we can't fly right into space!

  13. I have a question. If there are more molecules of air down on the surface of the Earth, are there more molecules of water at the bottom of the ocean than on the top?

  14. haha how many takes did it take you to keep a straight face while filming the scene with the helium voice ? I legit had to watch that part about 5 times before I could listen to the explanation properly; I couldn't stop laughing.

  15. I lost it at the fire part xD I'm always happy to see these videos, they're so good

  16. Wait, why did the hot air leak out the bottom in the first place? Isn't hot air supposed to keep rising in the first place? Explain please :/

  17. The 30 second long DropBox ad was objectionably long the first time I saw it. It was waaaaay too long the second, third and forth time. Still I thank you for your vids.

  18. You could mention that altitude is maintained when the total mass of the balloon and the air inside it equals the amount of air it displaces. To increase altitude i.e., get up where the air is thinner, the air inside the balloon has to get hotter.

  19. As mentioned, weather balloons don't have a hole at the bottom, so they keep getting bigger until they burst. Unless…. They enter a cloud with super-cooled water drops in them, and start accumulating ice. Then they get heavy and start to fall- into warmer air where the ice melts. And they can bounce around for hours around the same height, and if they are fitted with a radar reflector, they make a great impersonation of an unidentified aircraft in distress.

  20. well done but as nitin said it already i think there is a mistake too at 5.10 about why ships float, the weight of displaced water is equal to the weight of ship, the reason is density, ship has overall lower density due to its air filled bottom. This problem came up on the physics girl channel and even I had it wrong :'(

  21. wait what i was in the year 1016 suddenly i have a youtube channel in 2016 and am writing this comment while i have 60 seconds until
    wait what i was in the year 1016 suddenly i have a youtube channel in 2016 and am writing this comment while i have 60 seconds until…

  22. I have no idea what is the difference between the incorrect and correct version

  23. if you make a vacuum chamber that, when depressurised, weighs less than its volume in air would, would that float?

  24. I know how hot air balloons work but the way you have explained it in this video was very hard to understand and confusing . alot of effort went into this I know.

  25. 0:42 i cn see my dads old balloon lowest flying close ballooon in the bottom right

  26. Im scared so much of heights. We have a balcony that is like 5 meters above ground and I feel like im on top of the Mt.Everest.

  27. wow i have a better understanding of temperature and pressure from this video thanks!!! was so confused in physcis 101 and 102

  28. I hope you liked Albuquerque and the Balloon Festival! I love your videos!

  29. Why does the pressure between the outside and the inside have to stay the same?

  30. You remind me a bit of smarter every day. Good production quality and editing and audio. Plus, I learned something on this, my first video I have seen on this channel. Subscribed.

  31. "The air is falling down underneath us" ?
    With a stationary tethered balloon?
    You clearly don't understand bouyancy at all.
    Your explanation is simply wrong.
    You should not set yourself up to teach if you don't have the necessary knowledge.
    You are totally misleading others who wish to learn. Just for youtube fame?
    I'm sorry, but you should be ashamed.

    I'm wondering how many of your other science videos are similarly flawed.
    Please stop.

  32. I have a tendency of smiling in spite of myself when I watch these videos. You're making the world a better place, keep it up!

  33. The flying pig pilot guy is really weird. He is at lots of different events in my area.

  34. Air is empty space…? I'm afraid I disagree. Empty space, as in outer space, isn't even actually empty.

  35. Excellent episode! We live in Albuquerque and have been to so many fiestas. It's a blast. Planning to be there again this year. Hope we see ya there!

  36. The Wright brothers were known for the first heavier than air aircraft that could fly with its own power. Most people know that they weren't the first to fly.

  37. Is that ballon fiesta your at in the video in Albuquerque, New Mexico? It looks like it, and if it is I am going to scream. I live very few hours from there and went this year.

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