Rainbow Density Experiment

Here's a cool density related science experiment you can do with your kids.  Take four glass and pour 3 tablespoons (45 mL) of water into each glass.  Put a couple of drops of red food coloring in one glass, yellow in another, green in another, and blue in the final glass.  Now add 1 tablespoon of sugar to one of the glasses and stir.  Add 2 tablespoons of sugar to a different glass, 3 tablespoons to a third glass, and 4 tablespoons of sugar to the final glass.  Stir until the sugar is dissolved.

Now here's the tricky part.  Slowly pour the glass with 3 tablespoons of sugar into the glass with 4 tablespoons of sugar.  Pour very slowly to avoid mixing the liquids.  Now slowly add the 2 tablespoon mixture and finally add the 1 tablespoon mixture.  If poured very slowly, the colors will remain separated because each layer has a different density.  The more sugar added to the water, the greater the liquid density.  The more dense liquid remains on the bottom with the less dense liquid at top.

Above is our first attempt, which didn't work so great as I tipped the glass too much and it mixed.  There is, however, a layer differentiation near the bottom with the yellow, green, and blue.  We tried it again (sorry, no picture) and it worked much better.  Try experimenting with more or less sugar.  What about salt?  Does it work as well as sugar?  Test it out!!!