If we were to ask which plant's leaves are the largest, the giant leaves of the king lily should undoubtedly be the answer. The king lily, an aquatic plant native to the tropical regions of South America, is most notable for its leaves, which are truly enormous—each one resembles a large round tabletop. Its leaves also have an upwardly curled edge that forms a ring around the perimeter, like a giant shallow disc floating on the water's surface. What's even more astonishing is that the king lily's giant leaves can act like small boats. A child sitting on the leaf would be as safe as a frog sitting on a lotus leaf, without sinking beneath the water.
Why do the king lily's leaves have such great buoyancy? The large area of contact between the leaves and the water surface naturally generates greater buoyancy. Moreover, the upwardly curled edge around the perimeter of the king lily's leaves, much like the gunwale of a boat, greatly increases the water-displacement volume. According to Archimedes' law—"an object immersed in a liquid (or gas) experiences an upward buoyant force equal to the weight of the liquid displaced by the object"—its buoyancy is exponentially increased. In addition, numerous small depressions filled with air can also be found on the king lily's leaves, further contributing to its enormous buoyancy.
Some might argue that relying solely on buoyancy wouldn't be sufficient to safely support a child's weight, as leaves are typically the softest parts of plants. If a localized area were to bear excessive weight, the leaf would easily deform, reducing its buoyancy. However, the king lily's leaf structure compensates for this flaw. Upon closer observation, one can see numerous thick veins on the leaf's underside, much like the steel reinforcements in concrete structures. Even under heavy localized pressure, these veins won't easily break. From a physics perspective, the king lily's leaf structure perfectly adheres to mechanical principles. Scientists have conducted specialized tests on the king lily's leaves, finding that a 1.2-meter-diameter leaf can support a weight of 20-30 kilograms, which far exceeds the weight of a child.