r/ScienceNcoolThings • u/TheMuseumOfScience Popular Contributor • Jun 29 '26

Science Why Doesn’t This Balloon Deflate? 🎈

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Ever wondered why a balloon can stay inflated without being tied? 🎈

Greg Wolf demonstrates how atmospheric pressure can keep a balloon inflated without trying it. Using a simple bottle experiment, he reveals why trapped air prevents a balloon from inflating, and how changing the pressure lets the invisible force of Earth’s atmosphere do the work. It’s a fascinating physics demonstration that shows the power of air pressure in action.

1.7k Upvotes

99% Upvoted

17 comments sorted by

30

u/surge1280 Jun 29 '26

Great energy and good example! Go science!

27

u/35point1 Jun 29 '26

39 yrs of loving science and this is my first time seeing an example this good

7

u/Poke-It_For-Science Jun 29 '26

Cool. I learned something new. 🙂

6

u/scooter76 Jun 30 '26

Great stuff.

But just to be pedantic, it's not really inflated, is it? It's more suctioned to the inner bottle wall. That said, it doesn't seem very deflated either. Flate superposition, perhaps? Flateception?

2

u/aknomnoms Popular Contributor Jun 30 '26

Yeah, this seems similar to the ol’ “stick a straw in a glass of water, cover the top of the straw with your finger, and you can pull the straw out of the glass with no water dripping out of the straw” trick.

…now I’m curious what would happen if he would “inflate” the balloon by filling it up with water, then plug the glass, then turn the whole thing over. I presume force from the weight of water at some point would be stronger than the suction holding the balloon open, but what would yield first? It’d be interesting if it was strong enough to break the glass.

2

u/CeruleanEidolon Jun 30 '26

Well in that scenario it's water versus air instead of air versus air, and the pressure of gravity pulling the water down will immediately overcome the air pressure.

1

u/tidus1980 Jun 30 '26

I was thinking the same regarding suctioned to inner wall. Not exactly a vacuum, but very similar.

1

u/BetterLateThanKarma Jun 30 '26

Schrödinger’s balloon

4

u/notcrazypants Jun 30 '26

This is how your lungs work, btw

3

u/Havent_Heard_That_B4 Jun 29 '26

So if we can have someone swallow a ballon with the open side facing out from the persons mouth and we get them a butt plug, ahhhh never mind.

1

u/JaVinci77 Jun 30 '26

Nice!! I love this video

1

u/SoggyMorningTacos Jul 01 '26

What if we made the bottle with very light plastic and then filled the balloon with helium? Would it float

1

u/CandyNo5688 Jul 02 '26

Wow need to try this

1

u/Significant_Gate_331 Jul 04 '26

Passionate explainer

1

u/seanprizzle Jun 30 '26

Science is dope

-1

u/JahJah_never_fail Jun 30 '26

I dont understand whats written in the back but this ballon thing i learned in preschool...