An international team of scientists has created a portable water purifier that works simply by shaking it for three seconds and setting it to float in wild water. It could be a breakthrough device for water treatment in emergency situations and, best of all, it's estimated to cost less than $25 to produce.

This low-cost and simplicity of operation disguise the sophistication of the science involved however: shaking the canister generates enough power for it to auto-analyze the water and activate an appropriate disinfection process. It then floats in the liquid and, as it bobs, movement of water against its surface creates an electrostatic charge that kills microbes.

That extraordinary combination of processes can disinfect a liter of water in 20 minutes, to provide reliable safe drinking water without needing any chemicals, battery or external power source.