A Highlands Ranch STEM student creates a water testing triumph

Gitanjali Rao’s eyes dance and a smile lights up her face as she clutches an unassuming bright blue box. A 12-year-old Lone Tree resident and 7th grader at STEM School Highlands Ranch, Rao was named “America’s Top Young Scientist” and awarded $25,000 last October in a contest sponsored by 3M and Discovery Education. The box is Rao’s winning invention—and it just might hold the key to transforming how water is tested for lead.

“I’d been following the Flint water crisis and was appalled by how many people were affected. I decided to take action and create a solution,” Rao says.

She knew that the mainstay of water testing—strips—aren’t very accurate, and more reliable tests require samples be sent to labs, which costs time and money. Named Tethys after the Greek goddess of fresh water, Rao’s design relies on a carbon nanotube sensor to detect lead—making it more accurate than strips—and a processor that measures the resistance amounts. Within seconds, results are sent over Bluetooth to an app on the user’s smartphone.

Rao has big plans for Tethys. She hopes to expand the contaminants it tests for and she envisions a day when every home has one. She also has big plans for herself. While she enjoys fencing, baking and traveling, this young scientist has gene editing next on her radar.  

“I want to change the world,” she says.