If you just dropped your smart phone, shattering its pristine glass cover, take heart: Physicists are working on it. Engineers know that residual stresses left over after bending or heating glass change its properties in surprising ways—Prince Rupert's drops (shown) can withstand a hammer blow to the head but shatter when snipped at the tail—but they know little about how such stresses form or how they work. Now, a team of theorists and experimentalists has taken a step toward an answer. The researchers first created a glasslike mix by suspending microscopic plastic beads in a liquid and twisting it between two plates. By controlling how quickly and for how long they twisted the liquid-bead mix, they found that they could control the stress left over after the plates stopped spinning. What's more, as they report this month in Physical Review Letters, they were able to predict these stresses using a mix of math and computer simulations, steps that could lead the way toward lighter, stronger glasses for smart phones, car windows, or maybe just a nice pair of earrings. In the meantime, you might want to hold your iPhone with a slightly tighter grip.
See more ScienceShots.