Ph Scale
What Is Ph?
pH is a number that tells us how acidic or basic a liquid is.
Acids have low pH numbers, bases have high pH numbers, and neutral substances sit in the middle.
The Ph Scale
The scale runs from 0 to 14.
- 0‑6 – acidic (like lemon juice)
- 7 – neutral (pure water)
- 8‑14 – basic or alkaline (like baking soda solution)
A lower number means a stronger acid, and a higher number means a stronger base.
Everyday Examples
| pH range | Common example | Why it matters |
|---|---|---|
| 0‑2 | Stomach acid | Helps digest food |
| 3‑4 | Orange juice | Gives a tart taste |
| 5‑6 | Milk | Slightly acidic, safe to drink |
| 7 | Water | Ideal for most plants |
| 8‑9 | Sea water | Supports marine life |
| 10‑12 | Soap water | Helps clean skin and clothes |
| 13‑14 | Bleach | Very strong base, used for disinfection |
Why It Matters
Knowing the pH of a substance helps scientists and engineers:
- Keep pools safe for swimming.
- Grow crops that need the right soil acidity.
- Make foods taste good and stay fresh.
- Protect the environment by monitoring water quality.
Understanding the pH scale lets us predict how substances will react, keep things clean, and stay healthy.