Scientists have finally cracked one of physics’ nuttiest mysteries: why do Brazil nuts always find their way to the top of the bag? If you’ve ever opened a packet of mixed nuts, you may have noticed that you always find the largest nuts, such as Brazil nuts, at the top.Particles of varying dimensions tend to separate by size, with larger items working their way to the top. With the use of time-lapse 3D imagery and some serious packet jostling, scientists have finally shown how the ‘Brazil nut effect’ works.
By shaking a mixture of peanuts and Brazil nuts and taking a 3D X-ray scan after each shake, the scientists discovered the forces behind the Brazil nuts’ inevitable rise. The secret, they say, is in the larger nuts’ orientation.