2B40.59 Hot & Cold Layers

Demonstrate floating depends on density. Slowly add hot water until full. The top half will turn green where the water mixes. The bottom half stays blue.

Picture: Not yet available

Setup Requirements: Some time needed to heat up water on hotplate in class. Cold water can be prepared before class. Color hot water with yellow food coloring. Color cold water with blue food coloring. Fill cylinder about 2/3 full with cold water.

Equations: Whether it sinks or floats depends on the ratio of the density of the top layer to the density of the bottom layer. Density depends on temperature.

Safety Issues: Hotplate, hot water