The Brazil Nut Effect

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If you've ever wondered how Brazil nuts always seem to end up at the top of your mixed nuts, this is the video for you! In this FYFD video, Nicole explains the Brazil nut effect and granular convection.
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Thanks to my Patreon patrons and FYFD supporters who help make FYFD and FYFD video possible!
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Granular convection footage courtesy of Matthias Möbius and the Jaeger and Nagel Research Groups, University of Chicago. nagelgroup.uchicago.edu/
Special thanks to Sidney Nagel and Irmgard Bischofberger!
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Want to learn more about granular convection? Here's some of the literature I used to write this video:
- J. Knight et al., "Vibration-induced size separation in granular media: the convection connection"
journals.aps.org/prl/abstract/...
- E. Ehrichs et al., "Granular convection observed by magnetic resonance imaging"
science.sciencemag.org/content...
- J. Knight et al., "Experimental study of granular convection"
journals.aps.org/pre/abstract/...
- A. Kudrolli, "Size separation in vibrated granular material"
iopscience.iop.org/article/10....
- M. Metzger et al., "All the Brazil nuts are not on top: vibration induced granular size segregation of binary, ternary, and multi-sized mixtures"
www.sciencedirect.com/science/...
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FYFD video is written and hosted by Nicole Sharp, Ph.D.

Опубликовано:

5 июл 2024

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Комментарии : 59

@dragonflycn 8 лет назад

There are references at the end in the video. That's awesome! More people should totally do that! The explanation illustrations were also very helpful!

@michaelwinter742 7 лет назад

You are very smart and good at explaining things. Thank you for the happiness that is watching your videos.

@destrad3 8 лет назад

thanks for the video! i'm actually writing a paper on the brazil nut effect (intro physics, so not terribly complex) and your video helps in how i'll be structuring my research. thanks again!

@theriveroffaith852 5 лет назад

Thanks! It was so hard to find this!

@itskelvinn 8 лет назад

I wouldve never thought the effect reversed in a cone shaped cup

@mike0rr 8 лет назад

All these Legos! I'm in love with this channel!

@bobburt 8 лет назад

Huh. This is actually really interesting. My whole life I knew "the small stuff always ends up on the bottom" and never knew why, or how. But now there's a very good explanation behind it haha.

@melanieenmats 8 лет назад

Loved that rice animation.Nice videos thx.

@zanthornton 5 лет назад

Excellent! Love the lego, rockets, varied fun STEM items! I will subscribe!

@MidtownSkyport 8 лет назад

I knew the small lego pieces always ended up at the bottom of the box but I never knew why. Thanks, FYFD :)

@fyfluiddynamics 8 лет назад

+MidtownSkyport Hey, there's another great application I could have referenced! You'd think it might have occurred to me with all those Legos sitting in the background. Thanks for watching!

@idoperry3752 8 лет назад

cool video!

@mastertrey4683 6 лет назад

This is really neat

@TheZenytram 8 лет назад

I'm from Brazil and never ever heard of this effect hahaha.

@volksboy62 8 лет назад

Is there a shape of container between Conical and Cylindrical that would cancel the effect outright? It would be nice if Mixed Nut companies could start using the new shape!

@fyfluiddynamics 8 лет назад

+volksboy62 I don't know if there's a way to completely stop the effect, but one recent paper did find that having many different sized particles suppressed it to some extent. That's what I reference near the end: if you have a bunch of different kinds of nuts in the mix, then you don't see as much separation by size. Thanks for watching!

@MRSTEEL15 2 года назад

I was hoping to learn more about the benefits of Brazil nuts, but it was still interesting, Mrs Sheldon Cooper :-)

@bhupeshpattanaik7150 3 года назад

#question , plz answer why it is not applicable for a box containing sand and some stones ...if we shake it ,stone will go down if your answer is density, then why in case of nut in rice it is not applicable as rice is more dense than nut still nut rises up

@MusiCaninesTheMusicalDogs 8 лет назад

I clicked on this video because I'm Brazilian and I had no idea about what it could be about! Lol! I thought this effect was solely due to density and how denser things tend to sink to the bottom due to gravity. It looks like I was wrong.

@meraki9301 5 лет назад

wow!

@vitriolix 8 лет назад

I seem to get this in my yard with the larger, crumbly, sharp, horrible shale rock constantly rising to the top of the dirt. I routinely rake them off the top and get rid of them but they sure enough reappear eventually again... could it be the same effects in something as densely packed as dirt?

@fyfluiddynamics 8 лет назад

+vitriolix I expect that it takes a lot longer for rocks to work their way to the surface, but I've read suggestions that this effect does have a role in that sort of situation. It could help explain why some areas - like New England or the Ozark region - seem to constantly grow rocks no matter how many times you clear them!

@vitriolix 8 лет назад

+fyfluiddynamics the effect seems to vastly increase in speed when it rains a lot (say, for instance, during an El Niño downpour).

@fyfluiddynamics 8 лет назад

+vitriolix That makes sense. The drainage would definitely help move things around.

@elsonleong1204 7 лет назад

does all kinds of nuts have this effect?

@CrossTheLine1000 8 лет назад

great Magnesium source

@OneDollarWilliam 8 лет назад

So, if I'm understanding this correctly, I could keep all of the good parts of the salad from sinking to the bottom by switching to conical bowls?

@fyfluiddynamics 8 лет назад

+Andrew Wilson Hmm, not sure that lettuce can really count as a particle in a salad. Probably shaking things upside down is still the best bet.

@mike0rr 8 лет назад

I would also think that switching the fluid from air to dressing would make it a very different situation. But it does make me wonder about the technical differences from what we would normally call a particle and something like a lettuce leaf.

@fyfluiddynamics 8 лет назад

I feel like this is the time for a joke about spherical cows. ;)

@OneDollarWilliam 8 лет назад

+Mike Orr This may be way off, but the impression I get is that big leaves of lettuce are able to resist shearing stress, but as their surface area decreases their resistance to shearing does also, so a chopped salad would exhibit more fluid like properties, and coleslaw even more. There's probably some math to define the point where (if you could call lettuce a plastic solid?) a piece is small enough to be a particle. Possible topic for a future episode +fyfluiddynamics?

@mike0rr 8 лет назад

Interesting. I do love dissecting arbitrary topics with a magnified lens of science :P

@humgryfat9793 7 лет назад

so this is why I get chip crumbs at the bottom?

@papalevies 8 лет назад

Crazy

@AndrewChason 8 лет назад

You're going to want to invest in a Lapel Mic. Good video during the parts you weren't on camera though. I liked the simple animations too.

@fyfluiddynamics 8 лет назад

+Andrew Chason Thanks. A lapel mic is on the wishlist. Audio is a bit challenging when you're in a big echoey cube. :)

@BurkinaFaso69 5 лет назад

Great to see a woman doing science video! Cool video too, you got my sub.

@buzzlightyear7706 5 лет назад

F-Yeah!!!Much better than The video made by, it’s OK to be smart The raisin bran effect 😀 They should give u a kickback on the advertisements for that video!

@GeneMoves 6 лет назад

i love brazil nuts! I'll take some :)

@Naked_Snake 5 лет назад

I've been eating Brazil nuts for a while without knowing it. I thought these were just really large almonds for some reason LOL

@hungothanh4913 5 лет назад

it is ok to be smart

@alcapone6796 8 лет назад

Please improve the audio quality

@thebigitchy 7 лет назад

Good mics are expensive

@erikziak1249 8 лет назад

Interesting fact about the conical cylinder. I know that some nuts are being sold in ice-cream cone like shaped containers. The Brazil Nut Effect still works. Maybe there is a critical angle, or the walls have to be really hard, not just wrapped paper. Maybe you covered this topic in one of your papers, but I will not read them, as I have no time, sorry. There are already a bunch of papers piling up in my „not read yet“ directory. And also I should be writing right now, but I just took a break... Btw. I like the Brazil Nuts and before watching this video I even did not know they are called Brazil Nuts.

@fyfluiddynamics 8 лет назад

In the experiment where they tested that conical container, they glued a layer of poppy seeds to the wall so that that it had the same roughness as the rest of the granular material. That difference in friction at the wall is probably what accounts for the difference between their results and the nuts sold in cones.

@erikziak1249 8 лет назад

And how did the convection work in a cylindrical container with poppy seeds glued on the walls? Maybe the downward acceleration of this layer, which was greater than gravitational acceleration "dragged" on the particles in contact with the wall, thus reversing the flow.

@fyfluiddynamics 8 лет назад

That was the situation I described in the video: with the conical container with the glued seeds, the convection rolls went down in the middle and up in a thin region along the sides. Sadly, I don't have video for that one. :)

@erikziak1249 8 лет назад

Yes, I got that. But how do glued seeds affect the convection flow in a cylindrical container? Is there a correlation between grain size and angle of the wall? Is there an effect of the bottom of the container too (full cones that end up in a point vs. containers with a circular flat bottom)? Sorry for asking these questions, but you got me thinking now. And I was finally writing! :-)

@fyfluiddynamics 8 лет назад

Ha, sorry, I misread. The clips in the video show convection in cylinders with glued poppy seeds, too. That's why the walls are lit up. I don't know if anyone knows the exact relationship between the grain size and the angle of the wall. As for writing, perhaps we both need a pact to get back to work! The Internet is way too distracting...

@johnjhill3 8 лет назад

Brazil nuts are wonderful, second only to cashews. Their smoothness and size feel good in the mouth. Lacking the bitterness of some nuts, their light flavor makes for a nice long chewing experience. They certainly *ought* to be at the top, thru physics or any other process! Where does your disdain for these treasures come from?

@fyfluiddynamics 8 лет назад

+Frank Drebbin Brazil nuts are not my favorite, but I actually don't have anything against them. ;-)