It’s hard to know exactly how much plastic trash is floating around in the ocean–one recent estimate was five trillion pieces, but most of the tiny scraps haven’t been measured yet. Researchers may soon have a better answer thanks in part to the creative work of kids as young as five.
Cesar Harada, a Hong Kong-based designer known for his shape-shifting sailing robot, started working with a group of children from a local school and ended up with an optical sensor that can automatically scan the ocean for data on trash.
The students, from Hong Kong Harbour School, had done beach cleanups before, but wanted to do more. “The school was interested in doing something a bit more creative,” says Harada.
While Harada helped make it happen, the final design was based on the kids’ ideas. “One kid had an idea of building a machine in the shape of a shark, so fish would be afraid and not be captured,” says Harada. “Another thought of having a big net so we could physically capture the plastic, and compare it to what we’ve sensed through the optical sensor. A very smart and scientific idea.”
Others suggested different ways to attract the plastic, and different shapes–like a whale-sized sensor, because typical sensors are tiny and can’t give a precise measurement over a large area. As they incorporated some of the ideas, the team hacked together a prototype from lamps, webcams, and plumbing supplies.
“We worked from the things that we had available at hand,” says Harada. “Some said, ‘I have a toy boat I can give to the experiment.'”
After testing a prototype in a swimming pool and the harbor, the team shared the plans on the DIY site Instructables. Now, Harada is collaborating with Ocean Cleanup–the organization led by a 20-year-old inventor who aims to use giant arrays to collect plastic trash–to put the sensors to work.