Gitanjali heard about the Flint water crisis while watching the news. She became interested in ways to measure the lead content in water. She developed a device based on carbon nanotubes that could send information via bluetooth. Rao collaborated with a research scientist at 3M. In 2017 Rao won the Discovery Education 3M Young Scientist Challenge and was awarded $25,000 for her invention, Tethys. Tethys contains a 9-volt battery, a lead sensing unit, a bluetooth extension and a processor. It uses carbon nanotubes, whose resistance changes in the presence of lead. - Wikipedia

A 12-year-old inventor's device for detecting lead in water | Gitanjali Rao | TEDxNashville

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