Surface Tension: Calculation & Unit Conversion

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SUMMARY

The discussion centers on calculating surface tension in relation to temperature using a capillary tube. The formula provided is surface tension = (density x radius of tube x height of column x gravity) / 2. Participants clarified that to obtain the correct units, density should be measured in g/cm², radius and height in cm, and gravity in cm/s², resulting in surface tension expressed in dynes/cm. Additionally, it was emphasized that surface tension is defined as force per unit length, correcting the misunderstanding regarding its calculation.

PREREQUISITES
  • Understanding of surface tension and its physical significance
  • Familiarity with measurement units in physics, particularly g/cm² and dynes/cm
  • Basic knowledge of fluid mechanics and capillary action
  • Proficiency in dimensional analysis and unit conversion
NEXT STEPS
  • Study the principles of capillary action in fluids
  • Learn about dimensional analysis in physics
  • Explore the relationship between temperature and surface tension in various liquids
  • Investigate the applications of surface tension in real-world scenarios, such as in detergents and surfactants
USEFUL FOR

Students in physics, particularly those focusing on fluid mechanics, researchers studying surface phenomena, and anyone involved in experimental physics related to temperature and material properties.

shamstar
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i am doing a physics assignment on the realationship between surface tension and temperature. i have calculated the surface tension at various temperatures using a capillary tube and measuring the height. i was given the formula:
surface tension=(densityxradius of tubeheight of columnxgravity)/ 2
i have calculated the surface tension, however, I am not sure what units it is in. density was measured in g/mm^2, radius and height were measured in mm, gravity was measured in mm/s. I am not sure if the answer will be dyns/cm or ergs/cm^2? or even something else? thankyou
 
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shamstar said:
i am doing a physics assignment on the realationship between surface tension and temperature. i have calculated the surface tension at various temperatures using a capillary tube and measuring the height. i was given the formula:
surface tension=(densityxradius of tubeheight of columnxgravity)/ 2
i have calculated the surface tension, however, I am not sure what units it is in. density was measured in g/mm^2, radius and height were measured in mm, gravity was measured in mm/s. I am not sure if the answer will be dyns/cm or ergs/cm^2? or even something else? thankyou

First of all convert all the mm reading to cm. Also measure the density in gms per cm^2 and g as cm/s^2. Now you will get in dynes/cm.
 
surface tension=force*length.

f=MLT^{-2}
Hence surface tension=ML^2T^{-2}
 
chaoseverlasting said:
surface tension=force*length.

f=MLT^{-2}
Hence surface tension=ML^2T^{-2}

I think that you have made some mistake. Surface tension is force/length.It is torque which is force*length(radius). So surface tension would be ML^0T^-2
 
thanyou both so much. let's hope a get an A on my assignment! thanks again
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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