Granular Convection

This is known as the "Brazil nut effect", and is explained well in this video . There are several factors at play, but note that a change in the shape of the container to an inverted cone would actually reverse the effect, i.e., the Brazil nuts would end up on the bottom.

Lets first imagine that if big nuts settle at bottom then small nuts could seep through them but if one layer of small nuts settled it would not allow big nuts to seep through them. I guess it can be one of the reason.

Even as it seems complicated to explain why the Brazil nuts raise to the top, one can easily verify that the configuration where the larger nuts are on top and the smaller ones on the botton possesses an increasing gradient of density from top to bottom, assuming the materials are similar and the smaller ones pack more efficiently. Thus, this configuration has a lower energy state compared to the homogenous mix (as a greater fraction of the mass sits closer to the ground) and is more stable.

Intuitively - When we shake, the smaller particles have more chance to go down easily between the gaps of larger ones. So smaller nuts end up at bottom

Stop copying questions from PBS's "It's Okay To Be Smart"!

Shaking increases the voids present between the particles. This causes easy seep in of the small particle, because of it being denser and upon action by the gravitational force.

Brazil nuts are bigger than smaller nuts so so if there was a layer of brazil nuts and a layer of smaller nuts, the smaller nuts potentially have a more likely chance of passing the gaps of the larger nuts

See, the nuts have spaces between them so if you shake them the smaller nuts will plummet through those spaces and will come at the bottom. And because of this the bigger nuts will come at the top. It is a bit oversimplified but if you are a beginner it is a good placeto start. This is called 'The Brazilian Nut' effect. Check out a video by Joe Hanson on his channel 'It's okay to be smart '.

Guys, don't overcomplicate it. Larger object just won't fit the hole, so it got hold up by objects that are below it while smaller objects can easily slide through to the bottom very easily, also Joe Hanson from It's Okay To Be Smart did a video about that on YouTube.

It’s called segregation,this happens due to different sizes, shapes and densities of the brazil nuts where the denser nut will accumulate and cake at the bottom

There's no generally accepted explanation, but a good one is that because of convection, the larger nuts are raised to the top

It is just like when you are eating chips and gradually you end with smaller and smaller pieces of the same and you want to get more! This can expain the answer of the question in a similar way.

Thank you

For example, If stones and sand are put in a jar unevenly, and if the jar is now shaken, the sand particles of lesser size will move through the gaps to the bottom (gravity playing the role of pulling the sand to the bottom).

A good big 'in will always come out on top over a good little 'un.

The big nuts. Let's first imagine that if big nuts settle at bottom then small nuts could seep through them but if one layer of small nuts settled it would not allow big nuts to seep through them. I guess it can be one of the reasons.

Poor question. Fact is that the most buoyant nuts will be work their way to thee top.

The ones of lesser weight will settle down when it is mixed.