We made our clouds!  The elementary students loved 'em.  One student was able to manage the eye dropper pretty well to add the diluted food coloring to the shaving cream, but the other students needed a little assistance.  Squirting the shaving cream atop the water was quite difficult for all of the students.

Each cloud produced different colors of "rain"--in amount and quantity.  After awhile the yellow, blue or green rain showers turned the water either blue or green.

P.S.  I dumped the glasses earlier than expected because the scene looked a little too "pub"-ish for an elementary classroom.