Rain with a sour pH
Rain with a pH below 5.6 is called acid rain.
The river after the rain
A rain sample is tested with pH paper. A river fed by this rain slowly becomes more acidic, and fish struggle.
Which rain could do this?
What this lesson covers
The idea
Rain water with a pH less than 5.6 is called acid rain.
The river after the rain
A rain sample is tested with pH paper. A river fed by this rain slowly becomes more acidic, and fish struggle.
Which rain could do this?
- Rain with a very low pH, below 5.6
- Rain with a pH of 7
- Any rain, always
Find the acid-rain line
Slide the marker. See where the rain turns into acid rain.
Now sort six rain samples.
Below 5.6 is acid rain
Rain water with a pH less than 5.6 is called acid rain. When acid rain flows into rivers, it lowers the pH of the river water, and it becomes difficult for aquatic life to survive.
Fish and water plants live only in a narrow pH range, just like our body.
- Rain pH | Called
- 5.6 or more | rain water
- less than 5.6 | acid rain
Notes
Rain water with a pH less than 5.6 is called acid rain.
Check yourself
Acid rain has a pH …
A rain sample has pH 4.5. It is …
Acid rain flows into a river. The river water's pH …
Why is acid rain a problem for fish in a river?
- more than 7. More than 7 would be basic.
- less than 5.6 — correct. Yes!
- exactly 7. pH 7 is neutral.
- ordinary rain water. Ordinary rain has a pH of 5.6 or more.
- basic rain. pH 4.5 is far below 7: acidic.
- acid rain — correct. Yes! 4.5 is less than 5.6.
- goes down — correct. Yes! The river becomes more acidic.
- goes up. Acid rain lowers the pH.
- stays exactly the same. Acid rain changes the river's pH.
- Fish do not need water. Fish live in water, and the water's pH matters to them.
- Aquatic life can survive only in a narrow range of pH — correct. Yes! The lowered pH makes survival difficult.
- Acid rain makes the river warm. The problem is the lowered pH.