What is a good high school level science experiment?

What are the concentrations of hydroxide and hydronium ions in a solution with a ph of 10.2?

Put these processes of the water cycle in the correct order, starting at the point where the water is in the lake: 1. water evaporates into the atmosphere 2. rain, snow, or other precipitation falls 3. water collects into larger bodies of water 4. water vapor condenses into liquid water

Asolid that forms and separates from a liquid mixture is called