Teachers' Domain: Density and Buoyancy: Mixing Hot and Cold Water
This 3-minute Flash video by PBS <i>Zoom</i> demonstrates how temperature affects the density of water. A middle school student demonstrates the concept by placing a one-liter bottle of <i>cold</i> water directly atop a second one-liter bottle of red-colored <i>warm</i> water. Watch the warm red water, which is less dense, rise visibly through the mouth of each bottle to the top of the cold water. The student then performs a second "control" experiment in which both bottles contain cold water (no water movement is observed). Teachers' Domain is an NSF-funded pathway of the ComPADRE Digital Library. It is a growing collection of more than 1,000 free educational resources compiled by researchers and experienced teachers to promote the use of digital resources in the classroom.