system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Is the 'neutral' of the pH scale based on something scientifically objective, or simply what is ideal for humans?
gpt
It's objective. pH is all about the fact that water molecules (H2O) sometimes separate into charged fragments known as ions: H+ and OH-. A neutral pH (such as is found in pure water) is the level at which the number of these two types of ions is equal. Adding other substances can skew the balance to Acidic (more H+) or Alkaline (more OH-).