Climbing Water

You might think water always goes downhill. But have you ever seen water climb uphill?

MATERIALS: 2 glass plates about 12 cm sq; a wooden splint, coffee stirrer, or strip of foil folded over a few times; a small pan or flat-bottomed dish; a rubber band; water

HOW TO DO IT: Hold the two glass plates together with rubber bands with the narrower spacer between them at one end. Put water in the pan, about 5-10mm deep. Stand the glass plate assembly up the tray. Observe the water. It Should be something like the Illustration below:

Because of surface tension and the capillary attraction between the molecules and the glass, the very thin space will attract water molecules to climb up the glass. In the area where the two plates are close together, there are not enough water molecules to attract each other. When the glass plates get apart, the water's surface tension prevents the molecular attraction of the glass from pulling the water molecules up so far.