Imagine a balloon that could float without using any lighter-than-air gas. Instead, it could simply have all of its air sucked out while maintaining its filled shape. Such a vacuum balloon, which could help ease the world’s current shortage of helium, can only be made if a new material existed that was strong enough to sustain the pressure generated by forcing out all that air while still being lightweight and flexible. Caltech materials scientist Julia Greer and her colleagues are on the path to developing such a material and many others that possess unheard-of combinations of properties. For example, they might create a material that is thermally insulating but also extremely lightweight, or one that is simultaneously strong, lightweight, and nonbreakable—properties that are generally thought to be mutually exclusive. Greer’s team has developed a method for constructing new structural materials by taking advantage of the unusual properties that solids can have at the nanometer scale, where features are measured in billionths of meters. In a paper published in the September 12 issue of the journal Science, the Caltech researchers explain how they used the method to produce a ceramic (e.g., a piece of chalk or a brick) that contains about 99.9 percent air yet is incredibly strong, and that can recover its original shape after being smashed by more than 50 percent.
When Apple introduced the Mac in 1984, it also introduced a consumer-friendly version of a revolutionary new way of navigating a computer screen, something that we all now take for granted: the graphical user interface (GUI) and mouse. Similarly, when Apple entered the crowded (and largely unsuccessful) market for MP3 players, it introduced the idea of an intuitive trackwheel to scroll through albums and songs. For the iPhone and the iPad, there was multi-touch. But, on the small face of a watch screen, multi-touch wasn’t a viable option. So, Ive and his team went back to traditional watch designs, reimagining the winder as the Apple Watch’s primary form of navigation. By clicking and turning the ‘crown,’ users can magnify, zoom and shuffle between various options. Not only is this a smart way of solving a specific technical challenge, but it’s also an elegant nod to classic watch design.