Demonstration 5

pH of Cement

Objective: The purpose of this demonstration is to show the reaction of water with cement and the accompanying change in pH.

Materials and Supplies:


  1. Fill a Petri dish half full of distilled water.
  2. If using universal indicator, place a drop in the water and mix. If solution is not yellow, add a drop of dilute acid to make it yellow. If using the pH paper, lay 2 strips on the bottom of the dish so the diameter of the dish is covered.
  3. Place the dish on the overhead.
  4. Into the solution or on top of the pH paper, place a spatula full of cement.
  5. Observe the change.

Video Clip

Expected Results:

As the cement mixes with the water, hydroxide ions are formed, thus changing the indicator solution to blue. Emphasis should be placed on the fact that a chemical reaction is occurring not a dissolving process.

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