The Most Powerful Force on Earth

Why is the surface of a lake flat, the surface in a glass of water curved, and the shape of a small drop of water nearly spherical? Does water change its shape depending on how much there is? What determines this shape?

This single-lesson course will start with a lecture on surface tension. This chemical property of liquid matter is a powerful force that determines the shape of liquid surfaces. Surfaces are important, because virtually all interactions between tangible objects occur through their surfaces… even near tigers!