For as long as she can remember, Madison Checketts has loved the beach. Yet when frequenting stretches of the coast around Escondido, California, on annual family vacations, she couldn’t help but notice all the plastic water bottles cluttering the sand and ocean.
“The beach is one of my favorite places to go, and seeing it all trashed up with plastic water bottles, I just felt like this needed to change,” Checketts says.
After learning more about plastic pollution and ways to reduce it, she designed what she calls the Eco-Hero. The gelatinous water bottle is actually edible.
The now 12-year-old student from Eagle Mountain, Utah, started working on the project in October 2021 as part of her elementary school’s science fair. After being selected as one of the students from her school to compete in the school district’s science fair, she won first place at a state science fair before advancing to a national competition. In September, Checketts was named one of the 30 finalists in the 2022 Broadcom Masters Competition, the country’s premier science, technology, engineering and math (STEM) competition for middle school students. There, she was surrounded by other young inventors who designed projects like a remote-controlled robotic hand that could be used in natural disaster situations and a foot-controlled welcome mat that can wirelessly unlock a door to help those with arthritis and other hand conditions.
In her early research, when Checketts asked herself what she could do to make the world a better place, she immediately thought about reducing plastic pollution. Plastic products like water bottles are designed as single-use items intended to be thrown out after use. Americans consume more than 30 billion plastic water bottles annually, with the vast majority not being recycled. After being tossed away, plastic water bottles often end up in the ocean, where more than 5.25 trillion pieces of plastic trash circulate.
Plastic pollution devastates marine environments and poses a specific threat to marine wildlife. Animals like turtles—Checketts’ favorite—may confuse plastic waste for prey and swallow it, which can block their stomachs, make them sick and cause other internal damage. Depending on environmental conditions and chemical properties, plastics can also leach toxic chemicals and contaminants into the ocean.
Checketts stumbled upon a website focused on reverse spherification—a method of enclosing a liquid in a gel membrane—and wondered if she could make an edible water bottle using this process. Reverse spherification was popularized by a team of chefs, creatives and researchers from the Spanish restaurant El Bulli in 2005. The process stems from another culinary technique pioneered in the 1940s called spherification—used to create culinary delights like the “popping boba” in bubble tea drinks—in which a liquid is turned into a semi-solid sphere. Compared to basic spherification, reverse spherification allows for the liquid encased in the membrane to remain a liquid for longer. The sphere itself can be bigger, too.
Checketts’ approach was based on further internet research about reverse spherification methods. She relied on a chemical reaction between two common food additives—a salt called calcium lactate and a natural polymer found in brown algae called sodium alginate. When mixed together, the chemicals form a cross link resulting in a gel membrane that traps liquid.
After some trial and error, Checketts made her final prototype by mixing calcium lactate, xanthan gum (another common food additive and thickening agent), lemon juice and water in a blender. She froze the calcium lactate solution in a rectangular mold and then placed the frozen rectangle in a sodium alginate solution, rotating it until a membrane began to form. Once the membrane was fully formed, after about seven minutes, Checketts removed the oval-shaped membrane from the sodium alginate solution and placed it in a bath of distilled water to stop the membrane from continuing to form. When she let the edible water bottle sit in the fridge submerged in a mixture of lemon juice and water, it lasted about three weeks before the membrane burst.
The Eco-Hero holds about three-quarters of a cup of water and costs about $1.20 to make. Basically, the consumer bites a hole at the top of the gelatinous membrane, drinks the water and then either eats the membrane or throws it away. In addition to being edible, the Eco-Hero is also biodegradable. Checketts says the drink tastes like water with a hint of lemon, and the edible membrane has the texture of a gummy bear and tastes slightly lemony but comes to have no taste as it’s chewed.
“It took a lot of tries to get the membrane strong enough so it wouldn’t pop in my hands,” Checketts says. “A lot of times when I tried to pick it up, it would just fall apart, and that was one of the biggest issues.”
She tested various concentrations of the calcium lactate, sodium alginate and xanthan gum to achieve the best results. Adding xanthan gum to the calcium lactate solution helped make the membrane stronger, but she says the outer layer and water tasted soapy. To overcome this problem, she added a teaspoon of lemon juice to the calcium lactate solution to improve the taste and make it last longer. The idea to add lemon juice to the water solution and use it as a preservative for the water bottle stemmed from her fifth-grade school science fair project, which focused on keeping strawberries from molding by coating them in lemon juice.
“She learned that hard work pays off, and I saw that with her as she went through the process and she got frustrated at times,” says Checketts’ mother, Missy Checketts. “I didn’t really have to do anything, just watch her try and try and try. The biggest thing I saw that she did was just to keep trying new things, and if it didn’t work, she would research something else and then try it again.”
Checketts isn’t the first to design an edible water bottle, and some of her predecessors influenced her work. One such product is the edible Ooho water bottle developed in 2014 by former Imperial College London design students Rodrigo García González, Pierre Paslier and Guillaume Couche. Ooho’s designers used a similar reverse spherification method to Checketts, but they instead opted to use calcium chloride as opposed to calcium lactate, and they did not use lemon juice or xanthan gum. Checketts was inspired by their work, but she wanted to make an edible water bottle that was bigger and more durable. The Ooho water bottles hold about 50 milliliters of water, whereas the Eco-Hero holds four times that at about 200 milliliters.
Daniel Rittschof, an environmental scientist at Duke University, says he has worked with the reverse spherification technology Checketts used in her project and believes her idea is a good one. “This is the kind of innovation that people need to do, and they need to figure out how to move forward,” Rittschof says. “[Checketts] is on the right path, because she wants to make a difference, and she’s learning chemistry and biology and a little bit of business.”
On a practical level, however, Rittschof questions if the design of the edible bottle would work, adding that it’s important to consider how safe it is to actually eat the container, what trace amounts of different chemicals are in the bottle, how the product would be transported from one place to another without rupturing and more. “From my perspective, this is an idea that if you actually look at it practically, the basic idea probably wouldn’t work, but that doesn’t mean you couldn’t pursue the idea until it could work,” he says. Several secondary issues would need to be addressed before the product could be sold or used on a large scale, Rittschof adds, but the concept of being able to eat the water bottle is a “really good idea.”
In her free time, Checketts likes to play soccer, craft jewelry, draw and spend time with family and friends. Now a seventh grader, she hopes to excel in her classes and to begin to think about taking more advanced courses next school year. When she grows up, she wants to find a way to combine her hobbies and studies, and either be an engineer, designer or soccer player.
As Checketts thinks about the future of the Eco-Hero, she says she wants to run more tests to improve the water bottle and make it resealable, stronger and bigger. She imagines her invention could be used during marathons or races—as runners stop for water, they’d be able to grab an Eco-Hero, drink the water and either eat or dispose of the membrane before continuing to run. Overall, she hopes the Eco-Hero encourages people to think sustainably and understand that everyone can make the world a better place.
“It doesn’t necessarily have to be in a big way,” says Checketts. “[People] can still make a difference in the world, even if it’s just in a small way.”