This child prodigy developed technology to detect lead in drinking water. Years later, she made her way to MIT. At 19, made history by winning the Stephen Hawking honour

Most children who hear about a major environmental crisis might wonder how it happened. Gitanjali Rao had another question: could she build something to help? Rao was only 10 when she began developing a device designed to detect lead in drinking water, inspired by the water crisis in Flint, Michigan. Her idea eventually became Tethys, a portable prototype that helped turn the young inventor into a nationally recognised scientist. Years later, her journey has taken her to MIT and, in 2025, to another milestone: becoming the first recipient of the Stephen Hawking Junior Medal for Science Communication.

The Flint Water Crisis Sparked an Idea

Rao's interest began after she learnt about lead contamination in Flint's drinking water. According to Guinness World Records, she started developing her device at just 10 years old. The problem she wanted to address was practical. Testing water for lead could involve test strips or sending samples to laboratories, while Rao wanted to explore whether technology could provide information more quickly and conveniently. Her prototype, named Tethys after the Greek Titan associated with freshwater, used carbon nanotubes as part of a sensor system. The device was designed to detect lead contamination and communicate the water's status through Bluetooth to a mobile application.

At 11, Her Invention Won a National Competition

In 2017, when Rao was 11, Tethys won the Discovery Education 3M Young Scientist Challenge, earning her the title of "America's Top Young Scientist". The technology relied on a property of carbon nanotubes: their electrical resistance can change in the presence of lead. Rao's concept combined that sensing mechanism with electronics capable of transmitting results to a smartphone. It was an ambitious idea for a middle-school student, but Tethys was only the beginning.

She Didn't Stop With Clean Water

As she grew older, Rao turned her attention to other problems. She developed Epione, a device aimed at helping with the early diagnosis of prescription opioid addiction, and Kindly, an anti-cyberbullying technology using artificial intelligence and natural-language processing. MIT says Kindly has since been recognised as a UNICEF "Digital Public Good" service and made accessible worldwide.

Her work and advocacy also led TIME to name her its first Kid of the Year in 2020. Guinness World Records later featured her among its young achievers. But Rao's focus has increasingly extended beyond inventing things herself. She has also encouraged other young people to see science as a way of solving problems around them.

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From Child Inventor to MIT

By 2025, the girl who had started experimenting with water-quality technology was studying biological engineering at the Massachusetts Institute of Technology. At MIT, Rao continued working in laboratories while developing another interest: communicating complicated scientific ideas to people outside the lab.

That work brought another major recognition. In April 2025, she received the first-ever Stephen Hawking Junior Medal for Science Communication at a ceremony at the Kennedy Centre in Washington. MIT reported the honour in July that year. Rao told MIT that scientists rarely spend enough time discussing why communicating science matters, pointing to Hawking as someone who excelled at making complex ideas accessible.