This 12-year-old girl built a robot that can find microplastics in the ocean
This 12-year-old girl built a robot that can find microplastics in the ocean Anna Du was one of 30 Broadcom Masters finalists. (Rachael Lallensack/Broadcom Masters)
This 12-year-old girl built a robot that can find microplastics in the ocean
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Anna Du noticed plastic scattered on the shoreline. She was walking along Castle Island’s beach. That's in South Boston. She reached down to pick it up. She quickly realized there were many more tiny pieces than she could handle.

“When I realized how many pieces there were. It seemed impossible,” says Du. She was in sixth grade at the time.

Du approached the problem like any good scientist. First, she did a little research. That’s how she learned that 8 million metric tons of plastic end up in the oceans every year. And there's an additional 150 million metric tons that are already there.

Then she got to work building something that could help solve the issue. She built a remote-operated vehicle. It is referred to as an ROV. Her ROV could move through water. It could spot plastics on the ocean floor.

Du entered her ROV in the Broadcom Masters competition. It is one of the top science, technology, engineering and math (STEM) contests. It is for young students around the world. 

The competition is organized by the Broadcom Foundation and Society for Science and the Public. It has been running for eight years. This year, nearly 5,000 sixth, seventh and eighth graders were nominated. This was after they competed in regional science fairs.  Of those, 2,500 applied online for consideration. That pool was narrowed down to 300 projects dubbed “Broadcom Masters.” The top 30 finalists gathered in Washington, D.C. to showcase their projects. The top prize was $25,000. There were other cash prizes as well. 

Du’s ROV is made with PVC pipes. It is inspired by ROVs of all sorts. For instance, it is like the Curiosity lander that spies on the surface of Mars. It is also like the deep sea arctic Nereid ROV at Woods Hole Oceanographic Institution (WHOI). Du’s ROV has two separate systems. There is a navigation system and a detection system. The navigation system is pretty simple. It uses propellers to move through the water. It also uses a novel combination of fishing weights and foam pool floats that allow it to move up and down.

“The real invention here is the sensing.” That's according to Dana Yoerger. He is a roboticist and engineer. He works with WHOI’s Nereid. It is a ROV that travels great distances in the arctic. It hosts a suite of sensors on board. These include acoustic, chemical and biological sensors. Du was in awe of Nereid and nicknamed her ROV Nereid Jr. But her vehicle has a different skill set than its namesake. “The ROV is nicely done for a 12-year-old and hers is quite clever,” Yoerger adds.

The detection system is the “actually cool part.” That's according to Du. She uses a high resolution infrared camera along with three different kinds of light to spot the plastic. Du’s detection methods are comprised of two different wavelengths of infrared light. They illuminate the absorption spectra in microplastics. This makes them stand out from the sand and plant life. 

She also uses visible light to spot unnatural colors. These might make the plastics stand out. (Du was also one of ten finalists in the Discovery Education 3M Young Scientist Challenge this year. You can see a demo in her application video.) The apparatus doesn’t actually collect the microplastics. But it does identify where they are accumulating. She has applied for a patent on the functional elements of the ROV.

“She has an impressive basic kind of engineering instinct to break down a problem like this and then go after it,” says Casey Machado. She is also a WHOI engineer who works with Nereid. “She was able to follow that up with the technical work, construction and design to make a working prototype, which is very cool. It’s sounds simple, but it’s a level of thinking that’s really impressive.”

When Du first read about the challenge of locating ocean microplastics she found out that they are unlike the Great Pacific Garbage Patch. They are not floating on the surface. She knew that an ROV would be the most efficient tool for the task. Taking buckets and buckets of water samples and analyzing them in a lab could never be done to the scale needed. She needed a mobile lab that could find the plastics in-situ.

Du attends public events and workshops at MIT. She has been going since she was five years old. She picked up the engineering skills necessary to build her ROV from these sessions. She also learned skills from maker labs at local libraries and YouTube. 

She says actually getting her device to move through water well was tricky—even down to choosing the right kind of glue. It would be used to hold the PVC pipes together. Before she added fishing weights, the ROV would flip over. This happened when she tried to move it up and down. There was a lot of trial and error as she tested her ROV in Boston Harbor.

When asked about future plans, she mentions wanting to somehow address the effects of climate change.

“Especially with climate change happening all around the world, I think there’s a lot of problems that could be solved with new inventions,” says Du. “Right now, I’m mainly just focusing on plastics because there’s still a long way to go.”

Du credits her parents for fostering and supporting her interest in STEM. For years they have been taking her to MIT’s student outreach activities on weekends. She says she has been able to meet students and scientists there. As a result, she has her sights set on attending the university and becoming an engineer.

“I know I want to be an engineer because I like building things to help solve world problems,” says Du. “But I’m not sure what kind of engineer I want to be yet.”

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How do you think Anna's invention could be helpful on a global scale?
Write your answers in the comments section below

  • Rubyr-eic
    1/08/2019 - 02:59 p.m.

    This is a lot like the boy who created television except younger she was only 12 and created a robot. I wonder they get these ideas and not give up.

  • MorgynB-dec
    1/14/2019 - 10:30 a.m.

    Her invention could be helpful on a global scale because we have so much trash in the ocean we can’t see since it so small. With her invention, we could clean out the ocean and fix up the earth little by little.

  • IzzyS-dec
    1/23/2019 - 09:49 a.m.

    I think this is cool because she is saving the environment.

  • TorresA-dec
    1/24/2019 - 09:26 a.m.

    Thats cool that a little girl can be more powerful than a adult people if they put there mind into it they can do anything.

  • ygadh-wim4
    2/07/2019 - 11:16 a.m.

    I think that Anna's invention could be very helpful on a global scale because because of this all the plastic trash in the ocean is being cleaned. If all the trash would would be in the oceans all of the water creatures would eat the plastic bags or covers and then,they would be in a situation of dying, Because of her invention she is helping the water creatures to live for a while.She did a great job inventing a robot that can find micro plastic in the oceans.

  • Chasev-mcc1
    2/26/2019 - 09:38 a.m.

    her invention could help the numbers of plastic go down on the global scale and the ocean could be much cleaner.

  • Emilyl-mcc1
    2/26/2019 - 09:43 a.m.

    I think it would be helpful for our environment and for all of our animals in the ocean because they die every day for all the plastic

  • Nelliec-mcc
    2/26/2019 - 09:44 a.m.

    I think it could help the global scale of the world because there might other things that her invention might be helpful for. I think her invention was very cool.

  • Carlaf-mcc
    2/26/2019 - 09:44 a.m.

    I think it will be helpful because then all the animals would stay safe and not choke or eat all the plastic.

  • Winnio-mcc
    2/26/2019 - 09:47 a.m.

    I think Anna invention could be helpful because it will help take the plastic out of the ocean. It will also be helpful because it will keep more sea life alive. On the global scale it will help all the oceans and then all oceans will be un-pullited and more sea life will be alive because all the plastic is killing the sea life.

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