Question

In the graph, "ppm" stands for parts per million. A concentration of one ppm is a ratio of one part to one million parts. Concentrations can also be expressed as a percentage. Why do you believe scientists choose ppm over percentage in

some cases?

Answer 1

so

Step-by-step explanation:

im a scientist that just happened to be procrastinating on my research while I browsed this site.

In my research, I measure the amount of water in rocks that "dont have any water in them" or in techinical terms "nominally anhydrous minerals". The amount of water in these kinds of rocks is extremely small, much less than 1%. Therefore, its helpful to have a unit that can account for these smaller percentages like ppm