Life, The Universe and Surface Tension
By: John Fortner, Julia Turner and Laura Mueler
Surface Tension is often seen as the rounding off on the surface of water, however there are many more properties to surface tension than this. For instance surface tension is actually between any two immiscible fluids. Also instead of actually working perpendicular to the surface of the fluid it actually works more on a principle of suspension. That is to say, the molecules of the water are pulling each other together and by placing something on its' surface you are forcing the molecules apart and so they resist, forcing the object to be suspended on its' surface. Though these are properties of surface tension, here aste the definitions of surface tension:
Surface tension can be described in two ways.The first and more common definition of surface tension is the force per unit length applied toward the center of mass of the fluid. This is often described as a film on the surface of a fluid formed because the molecules on the surface feel a net force towards the interior of the liquid. This surface tension is also what allows objects to remain suspended upon a fluid and causes the water to look more rounded than flat on the surface.
Molecules on the surface feel a net force inwards while molecules on the interior experience no net force.
General Chemistry Topic Review: Surface Tension
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch14/property.html#tension
The second definition of surface tension is described as the energy required to increase the surface area of a liquid by a unit amount. A way of describing this is to say it is the amount of energy used to force a given amount of molecules to the surface. Take for example a bag of marbles. Now to expand it's surface area you have to apply a good deal of energy say, to put your fist in the middle, or perhaps a large ball.
> Demonstrations
- Soap Boat
- Floating Needles
- Drops of Water
- Films of Water Soap
- Meniscus> Everyday Occurrences
> Equations and Further Explanations
link back to Newman's site
