Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


NYU physicists show way to count sweets in a jar -- from inside the jar

How many sweets fit into a jar? This question depends on the shapes and sizes of the sweets, the size of the jar, and how it is filled.

Surprisingly, this ancient question remains unanswered because of the complex geometry of the packing of the sweets. Moreover, as any contestant knows, guessing the number of sweets in the jar is difficult because the sweets located at the center of the jar are hidden from view and can't be counted. Researchers at New York University have now determined how sweets pack from inside the jar, making it easier to more accurately count them.

To answer the question of how particles pack in general, the NYU team made a transparent, fluorescent packing of oil droplets in water, which allowed it to record three-dimensional images and examine the local geometry of each member of the pack. In other words, what does a packing look like from the point of view of a grain within—i.e., a "granocentric" view?

Their findings, which appear in the latest issue of the journal Nature, show that packing strongly depends on the size distribution—larger particles pack with more neighbors than do smaller ones. Nevertheless, the average number of contacts per particle always stays the same to preserve mechanical stability.

These experimental clues led the researchers to develop a model that successfully captures the geometry, connectivity, and density of the observed sphere packings. This means that starting from a set of particles of known sizes, the density of packing can be determined, making it possible to guess the number of sweets in the jar. Indeed, the model was able to also predict experimentally observed trends in density for mixtures of particles of two different sizes with varying ratios.

Packing problems are important in technological settings as well, ranging from oil extraction through porous rocks to grain storage in silos to the compaction of pharmaceutical powders into tablets. The ability to predict the packing of polydisperse particles—a range of sizes in a single system—has significant impact on these and related technologies.

The research was conducted by the group led by Jasna Brujic, an assistant professor in NYU's Department of Physics, consisting of post-doctoral researchers Maxime Clusel and Eric Corwin and junior research scientist Alexander Siemens.

The Brujic Laboratory is part of NYU's Center for Soft Matter Research. For more on the Brujic Laboratory, go to; for more on the center, go to

James Devitt | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht OU-led team discovers rare, newborn tri-star system using ALMA
27.10.2016 | University of Oklahoma

nachricht First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>