3) In hardware design, a prototype is a hand-built model that represents a manufactured (easily replicable) product sufficiently for designers to visualize and test the design. The word prototype comes from the Latin words proto, meaning original, and typus, meaning form or model.
In chemistry, a salt is an ionic compound which is made up of two groups of oppositely charged ions. The ion with a positive charge is called a cation, and the one with a negative charge is called an anion.
Salt is a valuable commodity that could become hard to come by in a long term disaster situation. In Ancient Rome, salt was used as a form of currency because of itâs importance in preserving food. In fact, it is still used today as a form of currency in some parts of Africa. It was a prime mover of both economy and war.