strength

Imagine a book with latches on its pages: you can only flip a page if you know how to click its edge. That is roughly how the mechanical metamaterial we are about to discuss works. Each cell is a small mass inside a larger one, connected by an elastic beam. The beam can sit in two stable positions, like a switch.

Two pieces of sandpaper are pressed tightly together. As you start to slide them, they first catch on the rough spots, then suddenly slip. A fault in the Earth behaves much the same way during an earthquake. But there's a crucial detail: how far do you need to push the edges before the grip gives way? This distance is called the critical slip distance.

A solid under a microscope is not a monolith at all. In glass, polymer, or solidified resin, atoms are arranged randomly, and as a result, the material's properties vary from point to point. On large scales, we are used to describing them with smooth fields, like temperature or pressure in a room. But when you zoom down to a few atomic layers, that smoothness disappears.

Imagine an experienced chef during rush hour: suddenly a stove fails or a key ingredient runs out. Instead of panicking, he instantly reworks the recipes — speeding up some dishes, slowing down others, reallocating resources on the fly. This principle of dynamic adaptation underpins a new generation of ultra-reliable networks.

A wormhole is a tunnel connecting two distant regions of the universe. If such a wormhole existed and were traversable, a particle inside it would feel not only gravity but also a force from its own electric field. This force depends on how spacetime is curved around it.

A rubber band that gets thicker the harder you pull it. In electricity, this behavior is called negative capacitance: the more charge accumulates on the plates, the lower the voltage. A regular capacitor works the opposite way — voltage rises with charge.

A thin crack runs through glass. At first glance, the fracture line simply reflects the material's brittleness. But if you zoom in to the atomic level, the picture gets more complex: glass starts to resist differently when the crack accelerates.

A flat sheet with slits in a flow of water or air behaves like self-adjusting blinds. The pressure opens the gaps, and each strip of material tilts, turning into a miniature wing. Thus, even a sheet placed perpendicular to the flow generates not only drag but also significant lateral lift.

A thin film is like a taut sheet: the thinner it is, the harder it is to push through. Scientists have noticed that films made of very different materials (graphene, graphene oxide, polymers) resist projectile penetration surprisingly well under high-speed impact. And the thinner the film, the more energy it absorbs per unit mass.

A raindrop falling to the ground strikes with a certain force. But what if the drop isn't round but elongated like a cigar or flattened like a pancake? It turns out that shape is everything: the impact force can vary by more than a factor of ten just because of how the drop looks at the moment of impact.

In a regular battery, the electrolyte is liquid, and charged particles (ions) move freely. In the solid-state version, they squeeze through atomic 'corridors', like pedestrians in narrow passages. For a battery to work quickly, you need a material with high ionic conductivity.

Glass is a material with attitude. It seems fragile, but powerful invisible forces can live inside it. In chemically strengthened glass, the surface is compressed like a stretched rubber band, while the interior is stretched. When a fast object hits such glass, that rubber band snaps in many places at once. Scientists fired projectiles at glass and watched how it shattered.

Two pieces of graphite rub against each other, and the resistance vanishes as if an invisible film of oil separated them. Previously, this was only seen under a microscope, on tiny contact patches.

A water droplet falls onto a lotus leaf and bounces off without leaving a trace. Nature has perfected this self-cleaning marvel over millions of years, and engineers have long tried to replicate it. But if the droplet hits too fast, it shatters into splashes, losing mass and leaving wet marks on the surface.