Boiling water is one of the easiest and most reliable ways to get rid of dangerous parasites and bacteria, and thanks to MIT, the next time you go camping you might be able to leave the stove and matches at home. All you’ll need is a sponge, some unpopped bubble wrap and some sunlight. Like something out of an episode of MacGyver, the team at MIT, led by grad student George Ni and Gang Chen who heads up the school’s Department of Mechanical Engineering, the unique creation is known as a solar vapour generator and uses only ambient light as its power source. It even works on a cloudy day when the temperatures outside aren’t scorching.
To be clear, though, the sponge used in this breakthrough isn’t made from the same materials as the one you use to scrub dirty dishes. It’s made of graphite and carbon foam, and is able to convert 85 per cent of incoming sunlight to heat that can be used to produce steam and boil water.
The sponge was actually developed by the team back in 2014, but in order to boil water it required simulated sunlight that was 10 times as intense as you’d experience outdoors — even at high noon. To make it work with normal levels of sunlight, the team covered the sponge with a thin sheet of copper covered with a metallic film called a spectrally-selective absorber that absorbs sunlight and traps heat, to help minimise energy loss. But in order to generate enough heat to boil water to 100+C, the researchers discovered that good old bubble wrap was the last ingredient needed to thoroughly insulate the sponge.
The sponge’s ingredients may sound exotic, but they actually end up being a very cost-effective way to boil water, particularly when the only fuel needed is being given off by the sun for free. For developing parts of the world where clean water is hard to come by, it could be easily used on a larger scale to help purify water from lakes, wells and rivers.