New Method Uses Heat Flow To Levitate Variety Of Objects


Even though, researchers and scientists have been able to levitate specific types of material, a pair of UChicago undergraduate physics students helped in taking the science to a new level.

Fourth-year Mykhaylo Usatyuk and Third-year Frankie Fung led a team of UChicago researchers who demonstrated how to levitate a variety of objects ceramic and polyethylene spheres, ice particles, glass bubbles, thistle seeds and lint strands between a cold plate and a warm plate in a vacuum chamber.

In their work, researchers achieved a number of levitation breakthroughs, in terms of orientation, duration and method: The levitation lasted for more than an hour, as opposed to a few minutes; stability was achieved vertically and radially, as opposed to just vertically; and it used a temperature gradient rather than magnetic field or light. Their findings appeared January 20 in Applied Physics Letters.

In the experiment which was carried out, the bottom plate was kept normal at room temperature while a stainless steel cylinder filled with liquid nitrogen kept at negative 300 degrees Fahrenheit served as the top plate. The upward flow of heat from the warm to the cold plate kept the particles dangled indefinitely.

The best way to obtain high levitation stability is the geometrical design of the two plates. A proper ratio of their sizes and vertical spacing allows the warm air to flow around and conveniently confiscate the levitated objects when they drift away from the center. Another acute factor is that the thermal gradient needs to be pointing upward even a single change in a degree will greatly decrease the levitation stability.

According to the researchers, the apparatus offers a new ground-based platform to find out the dynamics of chemical, biological, and astrophysical systems in a microgravity environment.

Researchers achieved levitation of lint among other particles.

Levitation of macroscopic particles in a vacuum is of particular interest due to its wide applications in atmospheric, astrochemical and space research. And thermophoresis has been used in aerosol thermal precipitators, the manufacturing of optical fibers through vacuum deposition processes and nuclear reactor safety which apply progressive layers of atoms or molecules during fabrication.

The paper concluded that the levitation of materials in ground-based experiments provides an ideal platform for the study of particle dynamics and interactions in a pristine isolated environment. Chin’s lab is now looking at how to levitate macroscopic substances greater than a centimeter in size, as well as how these objects interact or aggregate in a weightless environment.