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 mineral composed of sodium and chlorine. Neither can exist alone in natural form. Together, they form the chemical compound that is sodium chloride. To geologists, salt is known as halite. Salt is a crystal of the isometric system, meaning it is usually cubic and perfectly symmetrical. Pure salt crystals are colorless, although a pile of them will appear to be white. Impurities in the crystals may cause salt to be various shades of yellow, red, blue or purple.