Things that sink: anchors, pirate treasure, bowling balls, water-logged cardboard, containers with holes. Things that don’t sink: tin foil flattened out and crimped on the edges, balloons filled with air, ships built such that their weight can displace an equivalent amount of water. Archimedes explained this better. Sinking versus floating involves density, weight dispersion, gravity, materials and experiment.

The Enrichment Class at Orange Avenue Elementary School in Milford built ships recently with grand hopes that they too would join the elite list of unsinkable things.

Melissa Costantini, one of two enrichment teachers in Milford’s public elementary schools, has been teaching her students at Orange Avenue, Calf Pen Meadow, Pumpkin Delight and Live Oaks schools about shipwrecks this first trimester. Costantini displays rusty anchors, pieces of driftwood, salvaged bottles and fishermen’s baskets alongside books on famous shipwrecks. Posters of past students’ ship research, detailing the circumstances of their design and downfall, decorate the white walls. These evidence a rich history of ingenuity, creativity, necessity, courage and defense as well as greed, risk and war, the teacher explains to her students.

Each of Costantini’s 50 fourth and fifth grade students among her four schools chose a ship to research. Every ship has a story: Titanic, U.S.S. Arizona, U.S.S. Maine, Lusitania, etc. The students continue to delve into those stories, the engineering, challenges they faced and consequences of icebergs, miscalculated capacities, weak rivets and wartime attacks.

Teams of students built ships from recycled materials, applying their new learning. Their challenge was to build an unsinkable ship with particular dimensions, discernible bow and stern and of course a cool name. Their creations were posted on Constantini’s class site.

Recently, they faced the Costantini challenge: present their ship, measure for compliance, assess teamwork, float it, endure weather and wartime attack, bear weight and reflect.  “It’s not about sink or swim,” Costantini assured them, “it’s about what we learn.”

A sturdy boat, named “the winning ship,” covered in silver duct tape, took the water first, listing to one side, but it floated. It sustained direct hits (Nerf darts and regular darts) to an air tank (Poland Springs bottle), but stayed afloat in the kiddie pool. It took side collisions, waves, wind and manufactured torrential rains, even though it was a bit top heavy.

Ava, Olivia, Melody, Caleb and Stephen presented the “S.S. Phoenix,” covered in recycled bubble wrap for protection against attacks. Their ship was 3.5 inches too long, a note for their redesign plans. The S.S. Phoenix endured the first tests, but when the monsoon hit, followed by a hurricane and a collision, the bow started taking on water and suffered a structural crack. Costantini asked, “Who remembers what happened when the Titanic started taking on water in the bow?” A class “Ooo” clearly indicated that they all knew: flashbacks of iceberg, collision, water seeping in, and a massive snap, which made the “unsinkable” sink with great loss of life.

The “Unative KKSMJ” ship design included several safety and buoyancy features while still staying within the challenge perimeters. The team sat their ship in the water. Most of its structure sat atop the bobbing waves, and James gasped, observing to himself, “It is sitting too high, like the Portland.” He knew a good deal about that ship’s tragic sinking in the Portland Gale of 1898, and here was evidence of how such a massive, reliable structure could fail against the forces of nature.

Each challenge became less about the Nerf darts and who got to measure, and more about immersing their knowledge within the waters of practice. Each time Costantini pulled a soggy ship from the pool, she asked, “What would you do differently and why?”

Their brains may have been rewinding the “Black Knight” capsizing or air tanks on the “Microceteceacharchara” (means tiny whale shark) gulping water, then imagining a redesign with careful attention to sealing materials or redistributing the weight over the bow.

They are still working on their reflections and ship models, but now they have a better understanding of what is really unsinkable.

Things that don’t sink: creativity when buoyed by opportunity, perseverance when the unexpected doesn’t mean failure, passion for learning when something you built — like the “Super Natural Steamer” — actually floats.