Thirteen-year-old Maanasa Mendu was watching tree branches sway in the wind when she noticed that the movement looked like piezoelectric materials—tiny devices that generate power through vibration. The insight helped inspire her design for a new type of renewable energy gadget.
Mendu won the grand prize in the Discovery Education 3M Young Scientist Challenge for her design, which uses small solar "leaves" to collect energy from the sun. As the wind blows or rain falls on the leaves, they also capture energy through vibration.
In an earlier version of the design, she focused on wind energy, trying to solve the problem of how to capture the wind in urban areas where giant wind turbines don't make sense. But as she developed the idea, she realized that she could do more.
"I realized that there are a lot more untapped energy sources in our environment, like solar power and precipitation," she says.
By harnessing multiple sources of power, the device can work more steadily. "If my device just relies on one specific environmental condition, the power output can vary throughout the day," she says. "Whereas if it relies on multiple environmental conditions—like sunlight intensity, wind speed, precipitation—all of these factors could create a more stable power source with a higher power output."
A prototype of the device, with three "leaves" made of recycled materials, cost $5 to produce. After charging for a day, the device can power a 15-watt light bulb for eight hours. With more leaves, the gadget could produce more power.
Mendu spent three months working with a mentor from 3M to develop the idea and plans to keep pushing it further now, increasing the efficiency and testing different configurations. After more real-world tests, she hopes to partner with social entrepreneurs or organizations to help deploy it around the world—particularly in countries like India, where there's need for more low-cost renewable energy.
She thinks there are some advantages to being a young inventor. "We're more curious," she says. "Older engineers, they're more experienced, they understand the material really well, and they try to find a standard method of approaching a problem...improving another design. Whereas student inventors try to seek inspiration from everyday things. I feel like they connect the dots better."
Her own inspiration from nature—watching tree branches—is one example of connecting those dots. "Students have a more open mindset," she says. "They even try crazy and stupid-sounding ideas."