Getting Ready:
The level of preparation is related to the number of indicators used. Four indicators requires eight 1000ml cylinders or beakers. For classroom use, smaller containers can be used. If glassware is unavailable, use the lower half of soda bottles. Fill each container to the mid point with water. To every other container, add a teaspoon of household ammonia to make the water basic. For a large group, place the containers on light boxes to illuminate. Pre-measure four 1tsp containers of household ammonia and two 15ml containers of each indicator.

Presentation:
Explain to the audience that each container contains only water at this point. Indicate that the tubes will be used in pairs for the demo. Add the ammonmia to the even tubes only and stir. Empty the indicators into each cylinder and compare the water only tubes to the basic tubes. To each of the cylinders, add a cup of dry ice and allow the ice to sublime. Encourage the audience to watch the colors in each cylinder and note any change.

Views of the Demo: