Water stored in a reservoir is used to generate electricity as it flows down and into a river. The river flows to the ocean, where it evaporates to form clouds. Rain falls from the clouds into streams that flow into the reservoir.

Ateacher gives students four liquids commonly found in the kitchen - vinegar, apple juice, dish detergent, and milk - and ph indicator strips, which measure acidity. the teacher asks the students to put the liquids in order from most acidic to most basic. what type of investigation could the students conduct to determine the correct order for the liquids?