Water pH test

Summary

Use a pH test to find out whether different kinds of water are acidic, basic or neutral.

Science content

Chemistry: States of Matter, Properties of Materials (K-7)

Science competencies (+ questioning + manipulation + others that are in every activity)

Planning/conducting: measuring (non-standard K up, standard 2 up)

Planning/conducting: data collection/recording (K up)

Evaluating: inferring (3 up)

pH of Vancouver ocean and tap water in 2016

Lessons activity is in

Beach Exploration and Studies

Carbon exchange between air and water

Materials

water from different sources: seawater, drinking water, pond or fish tank water
pH test kit that can distinguish between pH 6, 7 and 8

Procedure

Test seawater for pH (it is generally pH 8 or basic).
Compare to drinking water (neutral or slightly acidic/basic).
Compare to stream water, pond water and fish tank water (usually neutral).
Students might also want to test the pH of their spit (neutral).

Water chemistry varies with the kind of rock that the water flows over/through, and the chemicals that are added during treatment.

Ocean water becomes more acidic as more carbon dioxide dissolves in it, which happens as the atmospheric carbon dioxide goes up.

Vancouver drinking water is from North Vancouver watersheds, and is naturally slightly acidic. The treatment process makes it a little higher pH.

From Metro Vancovuer website 2021:
Metro Vancouver currently delivers water with a pH of 7.7.
Adjusting the pH is an existing key component of Metro Vancouver’s water treatment process because our untreated source water is naturally slightly acidic. Increasing the pH to a target range of 8.3 to 8.5 will:
• Reduce the release of copper from pipes in buildings caused by low pH in the region’s water;
• Reduce leaks in pipes caused by copper corrosion;
• Help preserve the lifespan of pipes and hot water tanks; and
• Reduce green stains on tubs, sinks, and grout.

Grades taught

Gr 2

Gr 3

Gr 4

Gr 5

Gr 6

Activity