| # | Concept | Culture | Statement | Freq. |
|---|---|---|---|---|
| 1 | ph level in water | United States | Importance of maintaining neutral or slightly alkaline pH levels for drinking water quality | 1 |
| 2 | ph scale | US | Used to measure acidity or alkalinity of a solution | 1 |
| 3 | ph scale | United States | Commonly used in science education and for testing soil acidity | 1 |