Scientists highlight challenges in understanding grains and granular science

By the Editorial Team · Monday, June 29, 2026

Scientists at the University of Manchester are developing new computer models to better understand the unpredictable behavior of granular materials like grains and powders, which have long challenged researchers. This work is crucial for improving safety in industries such as agriculture and transportation and for enhancing the performance of space missions affected by soil mechanics on the Moon and Mars.

Scientists continue to grapple with the complex behavior of granular materials, a challenge that affects industries ranging from agriculture to transportation, and even space exploration. Despite centuries of study, researchers say there remains a significant gap in understanding how collections of irregular particles such as grains, powders, and soil interact en masse.

An exhibition at the Royal Society in London, held during the Summer Science Exhibition this week, seeks to draw attention to the state of granular science and the practical implications of this knowledge deficit. Anthony Thornton, a granular physics expert at the University of Manchester, highlights that while early scientific inquiry into the properties of powders and particles flourished over 200 years ago, focus shifted away with the rise of quantum mechanics. However, the complexities of granular materials continue to present unresolved challenges.

One area where these challenges manifest is in the design and operation of grain hoppers and industrial silos, which store bulk quantities of particulate matter. Contrary to conventional assumptions, the forces exerted by grains within these containers are not yet fully understood. Historically, grains were modeled similarly to fluids, treating particles as uniform spheres. But in reality, the angular shape of grains causes them to interlock and form “force chains,” irregular networks of contact forces that can lead to blockages. These blockages can be hazardous; in the United States alone, over 20 silo-related deaths occur annually when workers enter confined spaces to clear jams and are endangered by sudden shifts in the material.

Thornton’s team is developing computer models to better predict when and how these force chains develop. The implications extend beyond industrial safety. NASA has expressed interest in granular science to improve the understanding of lunar and Martian soil, as multiple planetary rovers have become immobilized due to unexpected soil behavior. A 2025 study attributed some of these mission difficulties to insufficient knowledge of extraterrestrial granular materials.

More common applications also illustrate the importance of understanding grains. For example, the partially filled packaging of consumer products such as soap powder and hot chocolate is partly designed to prevent force chains from forming, which would otherwise cause blockages during transport or use. Granular mechanics have also been implicated in rail safety incidents; investigations into train collisions near Talerddig, Powys in 2024 and Salisbury in 2021 cited failures in sanding systems. These systems deploy sand to improve train braking, but blockages from the sand can cause those systems to malfunction.

Despite the longstanding recognition of the problem, Thornton notes persistent skepticism in the scientific funding community. He frequently encounters disbelief that such problems remain unsolved centuries after their initial identification, emphasizing the need for continued research to develop practical solutions. The ongoing study of granular materials aims not only to advance fundamental science but also to address safety and operational challenges across diverse sectors.

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