Want to try the top one? Fill a glass halfway with water. Add an inch of oil. Add one drop of food colouring. Sprinkle salt on top. Density = gasps of awe.
The bottom one is red cabbage water (shred it, boil it, strain it) and add it to a base, a neutral, and an acid.
(here: baking soda and water, water, vinegar) pH = smiles of wonder
“The larger the island of knowledge, the longer the shoreline of wonder.” Ralph M. Sockman