The purpose of this experiment is to test for the presence of CO2 gas in exhaled breath.
Things Required:
Limewater (See experiment – Making Limewater for instructions.)
Straw
Pint jar
Directions:
Fill the jar one-half full with limewater. Use the straw to exhale into the limewater. Continue to exhale into the liquid until a distinctive colour is observed
This Is What Happens:
The water limewater turns from clear to a milky colour.
Science Behind It:
Limewater always turns milky when CO2 is mixed with it. The chemical in the limewater combines with the CO2 gas in the exhaled breath to form a white powder that is not soluble in water. The powder is called limestone. If the solution is allowed to stand for several hours, the powdery limestone will fall to the bottom of the jar.
