Lesson plan

Carbon exchange between air and water

Use pH indicator to show that carbon dioxide dissolves in water, and model the chemistry. Test different water sources.
Science content
Earth/Space: Sustainable practices, Interconnectedness (2, 5, 7)

Carbon in the air cycles with living things (see lesson on carbon exchange between living things and the air).
Carbon dioxide in the air also cycles into water and our oceans.
These are both fast carbon cycles.

Activity showing how CO2 dissolves in water to make it more acidic.

Optionally, Model the chemistry of CO2 combining with water to make carbonic acid (first part of carbonate precipitation activity).

Test other kinds of water (e.g. fish tank, pond, ocean) to see how acidic they are.
(Note: they will not necessarily get their acidity from dissolved carbon dioxide, but maybe from other water chemistry.)


Lesson 2 of 6 of a series on the Carbon Cycle.
Good image of the whole carbon cycle at https://www.britannica.com/science/carbon-cycle

Grades taught
Gr 2
Gr 3
Gr 5
Gr 6