I studied physics when I was young and learned some physicists believed glass was a kind of liquid not because it’s transparent but it’s not crystal, that is, molecules are moving. Every physicist teaches snowflakes are kind of crystal and changing into liquid at the melting point. Therefore, you shouldn’t ask them the definition of liquid when you find them making some coffee with a flask. They may not be able to distinguish the sea from liquid or fluid as I didn’t. Though it’s much more normal compared with people who considers a doughnut is identical to a coffee cup, having one hole. Sometimes they store paperbacks into a toaster oven like I was doing.