Freon tanks await recycling. Image courtesy U.S. Environmental Protection Agency.
Stable, nontoxic refrigerants changed the world, transforming food storage, expanding Sun Belt populations, even helping early movie theaters succeed. But they also wrecked the ozone layer — Earth’s shield against harmful ultraviolet radiation.
Today, as stockpiles dwindle — and prices rise — due to phase-outs set by the Montreal Protocols 30 years ago, the future of Freon and its successors remains in doubt.
4-D printing remains in its early stages, It’s certainly too early to tell if it’s anything more than a buzzword, let alone if its promise will translate into practicality. But the sorts of people who bet on these kinds of things are betting on it.
And why not? Suppose a structure could unfold itself, like origami. Imagine if walls could flex or stiffen in response to shifting loads, or if a buried pipe could change shape to accommodate varying water flows — or to pump water via peristalsis, like your digestive system. Through 4-D printing, nothing is set in stone unless you want it to be.
Left to our own devices and allowed to live without constant fear of death by hunger or violence, we devise some pretty startling stuff.
Sure, some of our better efforts don’t outlast our calamities, or go obsolete before their time or simply never get their chance to shine because no one yet recognizes the need for them. But you can’t keep a good idea down forever, as I explore in this list of …
OK, so that’s not color-changing ice cream. It’s a Neapolitan ice cream sandwich. So sue me.
It’s said that we eat first with our eyes. It’s also said that there’s nothing new under the sun. There are a lot of sayings, is my point, but this isn’t an article about that. It’s an article about color-changing food.
“But wait,” I hear some of you saying. “Food already changes color. How do you think we get brown bananas?” To which I reply that nobody likes a smart aleck. Or something about “out of the mouths of babes,” assuming you’re a babe. Because you’re not far off from some of the ways that food scientists are using to take color-changing foods to the next level, particularly in the frozen food aisle.
The faster you go, the less inclined the air becomes to get out of your way. This simple fact, which stood for years as an impediment to breaking the sound barrier, can also be ingeniously harnessed to create an engine capable of zipping along at supersonic speeds without the fuel weight required by rockets.
In this article, I trace the history, science and engineering behind this revolutionary “flying stovepipe,” from its theoretical birth during the biplane era to its modern military and commercial offshoots. By the time we’re done, you’ll understand…
