Meet California twins Henry and Jack Grover, whose sprayable hydrogel kept hot charcoal from reigniting for 27 minutes, nine times longer than water in their test

Twin brothers from Riverside, California, have developed a sprayable hydrogel designed to help prevent wildfires from reigniting. Henry Grover and his twin brother Jack began the project after learning that the 2025 Palisades fire had been started by an earlier blaze that reignited. Their work focused on whether a hydrogel could be applied to burned areas and help stop them from catching fire again.The twins' final gel hydrated in 15 minutes and prevented charcoal briquettes from relighting for 27 minutes, according to the Society for Science. They also developed a sprayer capable of projecting the gel up to 18.3 metres. Their project was titled “Sprayable Hydrogels for Preventing the Rekindling of Wildfires” and was featured among the 2026 Junior Innovators Challenge finalists.What inspired the twins to develop a fire-prevention hydrogelThe project was inspired by the 2025 Palisades fire in California. Henry and Jack realised that firefighters could struggle to apply enough water to burned areas to stop them from reigniting.They began exploring whether hydrogel could help solve this problem. Henry said, “We knew that hydrogel was capable of absorbing hundreds of times its weight in water and releasing it over a short period of time, so we wanted to use it to prevent rekindling.”How the twins tested different hydrogels to find the best materialThe twins began by soaking nine hydrogels in water and weighing them. They then dried the samples in an oven and measured them at 15-minute intervals. Next, they tested how well each material adhered to surfaces. They spread the hydrogels on leaves, hung the leaves vertically, and measured how much of the gel’s weight was lost from each leaf.These tests helped them narrow the options to two hydrogels. The brothers then compared how quickly the remaining materials hydrated. They soaked both in water and weighed them for up to three hours.The final hydrogel kept hot charcoal from relighting for 27 minutesThe twins selected sodium polyacrylate as their preferred material. It hydrated in 15 minutes. They applied the gel to hot charcoal briquettes and measured how long the charcoal took to reignite. In their test, briquettes sprayed with water relit after three minutes. Those treated with the hydrogel took 27 minutes to relight.The result showed a longer delay in reignition under the conditions of their experiment. Henry and Jack also designed a sprayer for applying the gel. The device was able to spray the material 18.3 metres. The Society for Science featured the work under the project title “Sprayable Hydrogels for Preventing the Rekindling of Wildfires”.From restoring a vintage robot to animating his own screenplayBeyond the wildfire project, Henry has worked on restoring a robot from the 1980s. He updated it so that it could work with modern technology. Henry said, “The change was nothing short of magical. From a robot covered in yellowed plastic, it turned into a fully functioning robot capable of pouring drinks and serving muffins.” He also enjoys 3D animation. He said, “I wrote a screenplay that I am now animating with characters modeled and rigged all by myself.”You use AI every day. Now get your AI Quotient. Take the AIQ test.