A backyard minipond serves as a canvas for nature's artwork in the winter. Embedded in the beauty is many a physics lesson: the rock that melts the ice above, the leaf that melts the ice below, the bubbles trapped beneath and within, and the forces at work in forming all those loops and squiggles.
The impulses of kids to walk on ice or try to break it are safely explored on a shallow minipond like this.
We were surprised to discover that beneath the ice was not water but air. After the ice forms, the water beneath continues to be absorbed into the underlying soil, leaving a gap.