Surface Tension of wood on water

[zorro]

Suppose a uniform cube of wood floats on the surface of water. Water wets it completely. Will it be buoyed up or down by surface tension?

The force of surface tension is tangential to the liquid surface (along the surface of liquid). So I think there is no effect on buoyancy of cube due to surface tension.

 

[Andy Resnick]

Cubes cause problems because of the edges (canthotaxis)- let's consider a sphere instead.

Perfect wetting will result in a thin film of fluid covering the sphere, but the sphere can still be buoyant. I'm not sure what parameters govern the film thickness.

 

[zorro]

I guess perfect wetting will result in a vertical force downwards (due to surface tension). So the sphere/cube will get buoyed down by the water (though by a small amount)
What is canthotaxis by the way?

 

[Andy Resnick]

Canthotaxis is a great word! It refers to the pinning of a contact line at a sharp edge: the contact angle can vary by an amount proportional to the angle subtended by the solid edge.

http://books.google.com/books?id=IO...d=0CB0Q6AEwAg#v=onepage&q=canthotaxis&f=false

 

[PJC01]

I can say that the surface tension of wood on water is a complex phenomenon that involves the interaction between the surface of the wood and the molecules of water. In this scenario, the wood cube is fully wetted by the water, meaning that the water molecules are attracted to the surface of the wood.

When a liquid wets a solid surface, the surface tension causes the liquid to spread out and form a thin layer on the solid surface. This results in a cohesive force between the liquid molecules, which creates a surface tension. However, in this case, the water molecules are already in contact with the surface of the wood, so the surface tension does not have a significant effect on the buoyancy of the cube.

The buoyancy of an object is determined by its weight and the density of the fluid it is immersed in. In this case, the wood cube is less dense than water, so it will float. The surface tension of the water may slightly affect the overall buoyancy, but it is not the main factor.

In conclusion, the surface tension of wood on water will not have a significant impact on the buoyancy of the wood cube in this scenario. The buoyancy is primarily determined by the density of the wood and the water. Further research and experiments may be needed to fully understand the role of surface tension in this situation.