What happens when the silvered coin is put on the flame

On heating the coin in the Bunsen flame, brass is formed by the zinc migrating into the surface layer of the copper. This gives a gold appearance to the coin. Brass is an alloy of copper containing between 18% and 40% of zinc.

Explanation:

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

i think the answer is terrae but not 100 percent sure. ▓▬▬ §