Final answer:
The method in question refers to the chemical development of fingerprints with silver nitrate, a technique used in forensic science to reveal latent prints on porous surfaces, even if they have been wet. The reaction of silver nitrate with the components of fingerprints makes them visible due to the precipitation of silver.
Step-by-step explanation:
The method that utilizes a silver-nitrate based reagent to develop latent fingerprints on porous surfaces that may have been wet at some point is often referred to as chemical development of fingerprints. In forensic science, this technique is particularly valuable because it can reveal latent prints on surfaces where they might not be visible under normal conditions. When the surface in question has been exposed to moisture, this method can still be effective due to the chemical interaction between the silver nitrate and the constituents of the latent fingerprints, such as salts and amino acids. The silver ions in the reagent react with these components, depositing silver on the ridges of the fingerprints and thus making them visible.
One common demonstration of silver nitrate's reactivity is when a clean piece of copper metal is immersed in a silver nitrate solution. A reaction occurs where silver metal begins to precipitate and copper ions enter into the solution. This visually striking change is a classic example of a redox reaction, showcasing the transfer of electrons that occurs during such chemical processes.