I saw this drink on Pinterest
But didn't want to go out and buy a bunch of sugary drinks so we made our own little experiment with salt.
2 cups of water, salt, food coloring, and a piece of paper were our tools.
Fill one cup with some salt (to make the water "heavier")
and the other with a few drops of food coloring.
A paper on top will keep the water from spilling all over the place. I had to help at this point since no one else was home!
Slide the paper out. We haven't perfected this move yet so we did it over the sink and did lose a bit of the water, but you get the point
He thought it was pretty cool and wanted to talk about why they weren't mixing together. I suggest trying this one over the sink or a big bowl until you master the slipping out the paper - maybe cardboard would work better?