noun
phase change; phase transition
Scientific term for a change between solid, liquid, gas, or other phases of matter.
水の相変化は0度で起こる。
The phase change of water occurs at 0 degrees.
この物質は高温で相変化を起こす。
This substance undergoes a phase change at high temperatures.
Compound of 相 (phase) and 変化 (change), a straightforward technical term.