Wednesday, 12 March 2014
The Phenomenon of Surface Tension and Capillarity Symptoms
Labels:
Physics
Some of you might have seen a needle floating on water. Or
never seen any mosquitoes or other insects can stand on water. This
phenomenon is closely related to the explanation of surface tension which will
be discussed in this section. Then, we also may have come up with events
in the form of ground water seeping up on the wall so that the wall becomes
wet. This incident in physics known as capillarity events. Okay! Now,
we get into the discussion.
Surface Tension
Let us observe that we make a needle floating on the
water surface as objects that undergo surface tension. Surface tension is
caused by the interaction of the molecules of liquid water on the surface of
the liquid. In the fluid inside a molecule surrounded by other molecules
around it, but no liquid on the surface of other molecules at the top of the
liquid molecules. This leads to an interesting molecular restoring force
when the molecule was lifted away from the surface, by which molecules at the
bottom surface of the liquid. Conversely, if the molecules on the surface
of the liquid is pressed, in this case given the needle, the bottom surface of
the molecular restoring force that will give him up, so that the upward
restoring force can sustain a needle fixed on the surface of the water without
sinking. In addition, because the needle gives field press (preassure) is
greater then the resulting pressure will be smaller, and the distribution of
the weight of the needle can be more evenly distributed.
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| Surface tension of molecular interactions seen objects and liquids |
Upward force to prop up the needle so as not to drown is
the surface tension coefficient multiplication with twice the length of the
needle. The length of the needle here is the surface in contact with the
liquid. The force required to lift the needle is the upward force
of gravity add up needle (mg). Essentially, an upward force (Archimedes
force) which is owned by the liquid must be greater than the weight of the
object style. In addition, the density of the liquid molecules can also
affect the surface tension. Because the greater liquid density, the
greater the upward force that it provides.
Capillarity
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| Water causes capillary concave meniscus events |
Capillarity caused by the interaction of the molecules in
the liquid. In the liquid molecules can be subjected to forces of adhesion
and cohesion.Style cohesion is the attraction between molecules in a liquid,
while the adhesion force is the attraction between molecules with other
molecules that are not similar, the container in which the ingredients are
liquid. If greater adhesion than cohesion as in the water with the surface
of the glass, the water will interact strongly with the surface of the glass so
that the water wets the glass and also above the liquid surface will be curved
(concave). This situation can cause the fluid to rise to the top by the
surface tension upward direction until the limit upward force to balance
gravity fluid is reached (resultant force on the y-axis = 0).So the water can
rise up in a small pipe commonly called a capillary tube.This is what happens
when water rises from the ground up through the wall.
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| Water can seep up through the wall cracks so it wets the wall is one example of capillarity symptoms |
Symptoms of this nature allows us to calculate the
capillary rise of water high in a cylindrical capillary pipe / tube with radius
r. The smaller the radius of the cylinder / tube, the higher the water to
rise in the cylinder.
There are several examples of capillarity symptoms that
occur in their daily lives, including:
1. The spread of water dripping on the tip of the
fabric
2. Kerosene wick stoves ride through
3. Rising water through xylem vessels / timber in
plants
4. Penetrated water to the top of the wall
5. The ink spreads on the paper surface
There are several things that can affect the capillarity
symptoms, including:
1. Value of the density of objects
2. Value of acceleration due to gravity
3. Effect of Adhesion and Cohesion
4. The radius of the capillary
5. Viscosity (Viscosity Substance)
Thank you for reading this review. Hopefully these
reviews can provide knowledge to the readers. And hopefully we can improve
and expand our horizons in the field of science, especially physics. Viva Scientifica!!!
Posted By : Dimas Nabil Simamora
