Surfer's Tension

cults3d

Apologies for that clever pun! The stick figure is crafted from solid PLA plastic, boasting a higher density than both water and olive oil yet effortlessly gliding along their boundary. This innovative creation is my submission to the #MakeItFloat challenge. Initially, I sought to design an object that would float on the oil-water interface by making it slightly less dense than water but denser than oil. However, I soon discovered that PLA's density far exceeds that of water, rendering this approach unfeasible. Not even the highest concentration of dissolved salt in water could match PLA's density. During a series of experiments with scraps of plastic, I stumbled upon an intriguing phenomenon. The oil exhibits lower surface tension and adheres more strongly to the plastic than water does, effectively wetting it. This unique combination allows the buoyancy of the oil to suspend the object at the surface, defying its higher weight compared to both liquids. The stick figure's surfing ability isn't achieved by displacing a greater mass of water or oil; instead, it is held aloft by the adhesive force exerted by the floating oil. This remarkable effect can be enhanced by dissolving salt in the water, which reduces the density difference between the two liquids and amplifies the surfing action.