is nothing something and if so or if not how, is water wet, if 2 people dropped a piece of bread on the opposite sides of the earth at the same time does the world temporarily become a sandwich...?

technically no

Explanation:

there are 2 definitions of sandwich. one is the food one: 'an item of food consisting of two pieces of bread with meat, cheese, or other filling between them, eaten as a light meal.' the earth isn't food so it can't be a sandwich. the 2nd definition is the verb : 'insert or squeeze (someone or something) between two other people or things, typically in a restricted space or so as to be uncomfortable.' by dropping a piece of bread on the opposite sides of the earth at the same time won't make the earth squished or uncomfortable, so no it can't be a sandwich ( or be sandwiched)

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).