During the movie we were able to understand the importance of surface tension in liquids that have open surfaces. Surface tension is a property of liquids that is described as a pulled that exists in liquid surfaces which is uniform in all directions. Surfaces act as if they are in tension; this tension force affects the shape and motion of liquids that have an open surface. The force is between molecules that repel each other when close to each other, and attract each other when they are far away. Surface tension is also known as surface energy. Surface tension is expressed as dynes-per-centimeter and surface energy is expressed as ergs per square centimeter.
Important concepts of surface tension where explained during the movie accompanied by experiments that proved many theories and procedures followed to understand the behavior of surface tension. Concepts like the magnitude of surface tension, surface tension boundary conditions, contact angles, pressure caused by curved surfaces, bubble nucleation, break-up of sheets of liquids, and the impact of a milk drop where shown. Also, we learned that motions could be caused by surface tension gradients, concentration gradients along surfaces, electrical and chemical effects at surfaces, and temperature gradients along surfaces. It is important that we understand that when dimensionless groups reflect a ratio of gravity to surface forces, and a ratio of internal forces to surface forces, to be small surface tension effects will be dominant. Surface tension: Surface tension is the result of molecular attraction near a free surface, causing the surface to act like a stretched membrane. Van der Waals forces: Is the attractive forces between molecules.
... some of the force in surface tension is cohesion and gravity. Surface Tension is the condition existing at the free surface of a liquid, resembling the properties ... placed horizontally on a water surface. Surface tension depends mainly upon the forces attraction between the particles within the given liquid and also upon the ...
Angle of Contact: The angle between a vertical container surface and the tangent to the line of contact between two fluids in the container, as in the case of a graduated cylinder half-filled with water, where the angle of contact is measured within the liquid between the vertical cylinder wall and a tangent to the meniscus. Gradient: The rate of change of a physical property like surface tension. Meniscus: A surface that is curved when two liquids attract. Momentum Flux: Rate of flow of momentum across a surface. Hydrostatic pressure: The pressure measured at a point in a fluid, due solely to the weight of the fluid in the column above the point.
Capillary action: The attraction of the surface of a liquid to the surface of a solid, which either elevates or depresses the liquid depending upon molecular surface forces.