It was over 2,000 years ago that Archimedes allegedly ran naked and dripping wet through the streets of Syracuse, Italy exclaiming “Eureka!” in exaltation over the discovery of a fundamental physical phenomena: buoyancy. This push and pull between gravity and the “buoyant” upward forces of a liquid are what keeps ships at sea (and, in the case of Archimedes, helped uncover a fraudulent royal crown).
But, while this discovery may be ancient, a team of French physicists has now discovered a new kind of buoyancy that they call “anti-gravity.” In both theoretical and experimental trials, the researchers found that objects, such as small toy boats, could float on the opposite side of levitated fluids instead of falling down due to gravity.
The cause of this bizarre physics discovery? Good vibrations.
Scientists have long known that vibrating a medium, like a body of water, at just the right frequency can cause strange physical properties to arise. Famously, Russian Nobel laureate and physicist, Pyotr Kapitza, discovered in 1951 that applying vibrations to a pendulum could create a secondary stable equilibrium point. While a normal pendulum swings down from left to right with gravity, Kapitiza’s vibrating pendulum could do the same, but pointed upwards, seemingly against the force of gravity.
In a new study, published Wednesday in the journal Nature, researchers discovered they can create a similar anti-gravity effect for buoyant objects by vibrating and levitating dense liquids in an enclosed glass chamber. Much more than a ‘gotcha’ to gravity, the scientists write exploring this phenomenon could have ripple effects in chemical engineering, where scientists use bubble filled columns as bioreactors.
“This counter-intuitive upside-down buoyancy phenomenon suggests that the stabilization of Rayleigh–Taylor instability through vibrations can be considered not only in itself but also as offering opportunities for new experiments in unexplored conditions,” write the authors, referencing a phenomenon that occurs between liquid surfaces of different densities, as their experiment used.