Mixing Soaps

Whenever the hand soap dispenser by the kitchen sink gets low my wife or I fill it up from a large container of soap below the sink in the cabinet.  On this occurrence, however, my wife emptied one large container and opened a new one, but the two soaps were not the same kind.  One was standard hand soap and the other was the foaming hand soap that's supposed to go in a different dispenser.  My wife didn't realize this at the time, until she noticed they didn't mix, as shown below.

What's going on here?  The two liquid soaps have different densities and do not mix.  The lower density soap sits at the top and the higher density soap sinks to the bottom.  Cool!  This is very similar to the standard oil and water experiments in which the oil and water clearly separate due to different densities.  The was another good opportunity to show off science to our daughters and offer an explanation.

The moral here is that science surrounds us.  You just have to look for it!