Foam, specially-coated copper, and bubble wrap are components of a simple but innovative new device that can boil water without electricity, the Massachusetts Institute of Technology announced on Monday.

The system, which MIT compares to a sponge, can heat water to 212 degrees under just the heat of the sun, and could be used for applications like sterilizing medical tools in settings without electricity. It even works on cloudy days, the university said, and a key point is that it does not need mirrors or lenses to help focus the sun’s energy.  

Bubble wrap covers the top of the puck-like device to help trap the sun’s heat— an idea that one of the researchers on the project got from his teenage daughters’ science fair project, according to MIT.

“This device offers a totally new design paradigm for solar steam generation,” Tao Deng, a professor at Shanghai Jiao Tong University who was not part of the research, said in a statement.

While this low-tech system isn’t designed to last as long as others that need to use optics that concentrate the sun’s energy, it is also less expensive, and MIT said that sheets of the material could be used to do things like desalinate water or treat wastewater.

The study describing the device— a solar vapor generator— was published recently in the journal Nature Energy.

Follow Rob Verger on Twitter: @robverger