SEP Design a Solution A simple bread recipe calls for 400 g of flour, 7 g of salt (NaCl), 1 g of yeast, and 0.3 L of water (H2O). You have exactly 0.6 mol of salt. If
you want to use all of the salt, how many loaves of bread could you make? How
much of each of the other ingredients would you need?

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.