– What makes water move on most dry materials?

Question

For example; when you wet half a printer paper, the rest of the paper soaks it super fast. The water will even climb upwards to spread.
Does dry material drag water towards itself, or does something make water move towards dry materials?

In: 2

Answer 1

You’re asking about a phenomenon called capillary action, whereby liquids can move in ways that defy gravity. What causes this effect is a combination of surface tension and adhesion.

Surface tension is caused by the tendency of water molecules to stick together. Water has one of the highest surface tensions of any liquid, because of how strongly water molecules bond together. This is why water strider’s are able to walk on water, they take advantage of surface tension!

Adhesion is more difficult to explain, but it’s the tendency of different compounds to stick together.