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An 11-year-old boy from Florida has designed a new kind of sandbag to better protect life and property from the ravages of saltwater floods. His invention took top honors at a science fair this week, earning him a $25,000 check and a trip to Costa Rica.

"Living in Florida, I'm keenly aware of hurricanes and saltwater flooding," the Discovery Education 3M Young Scientist Challenge grand prize winner Peyton Robertson, who is a sixth grader at the Pine Crest School in Ft. Lauderdale, Fla., told NBC News.

"Super-storm Sandy really got me concerned about how people can prepare for that damage from flooding. But today, the most common method of flood protection is sandbags. They are really heavy and difficult to transport and leave gaps in between the bags. So, I redesigned the bag," he explained.

Instead of sand, his bag is filled with a mixture of salt and an expandable polymer. When dry, it is lightweight, easy to move and easy to store. Once the bag is positioned, such as to create a barrier around a house, users hose it down with water. The polymer absorbs the water, swells and fills the volume of the bag.

"I use salt so they are heavier than any approaching seawater … but the twist is when you add salt to the bag it reduces the swelling of the polymer so you need to recalculate how much you put in," Robertson explained.

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In other words, the young scientist, who is already taking pre-calculus and trigonometry, realized an interaction between his super-absorbent polymer and salt that required him to calculate the precise mixture to add to the bag so that the full volume fills when water is added.

The bags also have a novel interlocking mechanism that connects them at their midpoints in order to prevent gaps that floodwaters can penetrate.

Robertson tested the bags in the bathtub and a kiddie pool where they easily outperformed traditional sand-filled sandbags. He next hopes to test them "in a real hurricane situation because that is the only way to figure out what glitches or whatever might be in the solution."

As winner of the Young Scientist Challenge, he was named "America's Top Young Scientist" at an award ceremony on Tuesday that also comes with the $25,000 check, which he can spend however he pleases, though has expressed interest in saving it for college.

In addition, Robertson and the other three top finalists will go on a trip next summer to Costa Rica. These are:

Brooke Martin from North Central High School in Spokane, Wash., who created the iCUPooch device that allows pet owners to video chat and give their pets a treat when away from home;



Srijay Kasturi, a home-school student from Reston, Va., who invented a device that helps the visually impaired detect objects in their path;



and Daniel Culver from Montrose High School in Montrose, Colo., who invented an indoor cookstove that reduces harmful carbon dioxide emissions.



Between now and the trip abroad, Robertson said he will continue to pursue his passions inside the classroom as well as hone his skills on the golf course, where he plays competitively.

"I usually shoot from the white tees somewhere around the low 80s, high 70s," he said. "So, I'm pretty good."

John Roach is a contributing writer for NBC News. To learn more about him, visit his website.