Rice is a staple food for billions of people, but scientists have now discovered it could also inspire a new generation of smart materials.
Researchers led by the University of Birmingham found that packed rice grains behave in a surprising way under pressure, opening the door to “soft” robots that adjust their stiffness automatically and protective equipment that reacts differently depending on the force of impact.
The team discovered that rice becomes weaker when squeezed quickly but stays stronger when pressure is applied slowly.
This unusual behavior, called “rate softening,” is rare in most materials.
Normally, materials either resist force consistently or become stronger when hit suddenly.
In rice, however, the opposite happens because the friction between the grains drops sharply at high speeds. As a result, the internal structure that holds the grains together becomes less stable during sudden impacts.
Using this insight, the researchers designed a new type of engineered material known as a metamaterial.
Metamaterials are built from combinations of substances arranged in special ways to produce properties not found in nature.
In this case, the scientists mixed rice-based granular units with other materials, such as sand, that become stronger under fast pressure. The combination created a material that can bend, buckle, or stiffen differently depending on whether the force is slow or sudden.
What makes this discovery especially exciting is that the material responds automatically without needing electronics, sensors, or power.
Instead of programming a device to react, the material’s own physical structure determines how it behaves. Slow movements trigger one response, while rapid impacts trigger another.
This speed-sensitive behavior could be extremely useful for soft robotics, a growing field focused on building machines that are flexible and safe to work alongside humans.
Traditional robots made of rigid metal can be dangerous in close contact with people.
Materials inspired by rice could help create lighter robots that are gentle during normal tasks but firm when needed, making them safer for workplaces, homes, and even medical settings.
The technology could also lead to smarter protective gear. Helmets, body armor, or sports padding made from such materials might stay flexible during everyday movement but instantly stiffen or absorb energy during a collision. Because the response happens naturally through physics, it would work instantly without batteries or sensors.
Beyond specific applications, the research shows how everyday materials can be transformed into advanced engineering solutions. By studying how simple grains interact, scientists can design systems that behave intelligently on their own.
Although more development is needed before these materials appear in real products, the findings suggest that something as ordinary as rice could help shape future technologies—from safer robots to adaptive safety equipment—simply by harnessing the hidden physics inside a handful of grains.
