* Formation of a precipitate: Silver nitrate (AgNO₃) reacts with sodium chloride (NaCl) in salt water to form silver chloride (AgCl) and sodium nitrate (NaNO₃). Silver chloride is a white, solid precipitate that is insoluble in water.

* New substances are formed: The original reactants (silver nitrate and sodium chloride) are transformed into entirely new substances (silver chloride and sodium nitrate). This is a hallmark of a chemical change.

* Evidence of a chemical change: The formation of the precipitate is visible evidence that a chemical reaction has occurred.

The chemical equation for the reaction is:

AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)

In summary: The reaction between silver nitrate and salt water involves the formation of new substances, a change in chemical composition, and visible evidence (precipitate), all indicating a chemical change.