Water wets, in the same way as the sun warms. Or that fire burns.
Seriously, this property of water, which is elegantly called ''wetness'', is attributed to the forces linking the molecules of water together.
When a drop of water isn't in contact with anything and isn't subject to pressure and it is perfectly spherical. But when it touches a surface, the drop runs into the surface.
Depending on the composition of the surface, the molecules of water stay more or less glued together. The wetness depends on the force of attraction between the molecules of water and the molecules of the material.
With a window, the attraction glass/water is very weak, the drop therefore has very little power to penetrate, it is practically spherical, and it rolls off the material.
On the other hand, with cotton, the attraction cotton/water would be very strong, and the drop will penetrate the surface and attach itself to it. In this case, yes, water wets.
Question submitted by: Wonder-Why.com
Answer submitted by: Wonder-Why.com