Where Freshwater Meets Saltwater

Here is a picture of the inquiry "Where Freshwater Meets Saltwater."  I did this with 7th grade students without too much mess.  If you would like to use this with younger students, I would suggest doing it as a demonstration.  I left it on my desk for several days because the whole school was talking about it and other students and teachers stopped in to see it.  It is a great way to talk about brackish water and density.