Slow physics: recording the ascent and descent of a water column

A glass filled with carbon dioxide gas upside down on a plate of waterconstitutes an excellent demonstration of the solubility of gases. If the waterlevel on the plate is maintained the CO₂ will slowly dissolve and the columnof water will rise inside the glass, without quite reaching the ceiling, before anopposite process sets in: the water level will even more slowly begin to sinkin a process which will take several years. We followed the process for severalmonths, recording images of the water column with 10 min to 1 h intervals.The physics of the process is discussed and modeled quantitatively.