[O-08] Poster presentations by senior high school students

[O08-P27] Elucidation of the Expression Conditions of the Inverse Mpemba Phenomenon

*Akira TADA¹, *Hiroto NAKANOU¹, *Kaede SUGAWARA¹, *Misaki SHIMURA¹, *Nana YAMAURA¹ (1.Hyogo Prefectural Himejihigashi Senior High School)

Keywords:Mpemba phenomenon, Inverse Mpemba phenomenon, condensation of water droplets, melting of ice crystals

When water is cooled under the same conditions, the "Mpemba phenomenon" is known in which water with a high temperature freezes relatively faster than water with a low temperature. On the other hand, in 2020, it was suggested that there may be an "Inverse Mpemba phenomenon" in which ice with a lower temperature melts relatively quickly, but its existence has not been confirmed.
The authors confirmed the existence of the Inverse Mpemba phenomenon from the results of 81 melting experiments under various conditions. In particular, when ice below -20 ° C melts, the Inverse Mpemba phenomenon is always observed, and the conditions of occurrence could be clarified. No Inverse Mpemba phenomenon is observed in purified water in a liquid state of 0 ° C or higher. The results of this study may bring new insights into the condensation of water droplets and the melting of ice crystals in the atmosphere.