Awesome Soap Pattern

Many of the small science experiments I've done with my daughters have involved density differences.  These include the Floating Egg, Lava in a Cup, Fireworks in a Jar, and the Homemade Lava Lamp experiment.  The other day we noticed, without officially doing an experiment, another example of density differences in the kitchen.  We recently filled the hand held soap dispenser next to the kitchen sink, but we filled it with a different type of soap.  A few days after filling the dispenser, we noticed the following.

The leftover soap at the bottom slowly, and by slowly I mean over several days, began to rise in snaky paths toward the top.  It's been about a week since I took this picture, and the snaky paths have continued to rise and are now about halfway to the top of the dispenser.  Very cool to look at!