Ice discs slingshot across a metal surface all on their own

Researchers have made a fascinating discovery about frozen discs of ice that can move independently across a specially designed metal surface. This groundbreaking finding, detailed in a recent publication in ACS Applied Materials and Interfaces, comes from the Virginia Tech lab led by mechanical engineer Jonathan Boreyko. Previously, Boreyko's team showcased a three-phase Leidenfrost effect involving water vapor, liquid water, and ice. This phenomenon occurs when water droplets are placed on a sufficiently hot skillet, allowing them to float and glide about due to steam cushions created underneath them. While this effect is known to occur with various liquids, including oils and alcohol, the temperature required for it to manifest varies. In the latest research, Boreyko's lab found that ice can also exhibit this effect, but under different conditions. When a flat ice disc is positioned on a heated aluminum surface, it doesn't levitate at the typical Leidenfrost temperature of 400 degrees Fahrenheit (about 204 degrees Celsius). Instead, a much higher temperature of 550 degrees Celsius (1,022 degrees Fahrenheit) is necessary for levitation to take place. Until this critical temperature is reached, the meltwater beneath the ice disc continues to boil in direct contact with the hot surface. However, once the threshold is crossed, a unique three-phase Leidenfrost effect occurs. The key lies in the temperature difference within the meltwater; the bottom layer boils while the top remains adhered to the ice. This intriguing discovery has practical implications, particularly in fields such as nuclear power, firefighting, and metal shaping, where rapid cooling is essential. In these applications, utilizing ice particles instead of liquid droplets may offer significant advantages, enhancing efficiency and effectiveness in heat management.