Tension Superficial
Ilustraciones
"Floating" insect
Insects do not float, they are heavier than water. Only objects lighter than water can float. Insects are prevented from sinking because of surface tension effects. The surface of the water behaves like a membrane that supports the weight of the insect.
Contact angle between aliquid and a solid
The contact angle between a liquid and a solid can be observed by placing a drop of the liquid on a flat surface of the solid. Contact angles are small when cohesive forces are small in relation to adhesive forces. Small contact angles result in a tendency of the fluid to "wet" the surface of the solid.
A drop of water
Surface tension tends to minimize energy in the surface of a liquid. This is the reason that water droplets tend to be spherical. The traditional teardrop shape of a water droplet is a result of gravity distorting the spherical shape.
Meniscus of mercury and water
When water and mercury are each placed in a capilary tube a different meniscus will be formed. Water will form a convex meniscus (water tends to wet the glass). Mercury because of it's large cohesive force, will form a concave meniscus that will behave in an opposite manner as water.
Can Steel float?
At first it would appear that the pin, which has a higher density than water, is floating on the surface. Careful observation will show that the surface of the water is depressed around the pin. The vertical component of surface tension is what supports the weight of the pin.
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