Difference between revisions of "Measure Viscosity"
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== Steps == | == Steps == | ||
=== Understanding Viscosity === | === Understanding Viscosity === | ||
| − | #Define viscosity. Viscosity measures a liquid’s resistance to flow.<ref> http://physics.info/viscosity/</ref> A fluid with high viscosity flows very slowly, like honey. A fluid with low viscosity flows quickly, like water. The unit for viscosity is a pascal second (Pa s).<ref>http://www.engineeringtoolbox.com/dynamic-absolute-kinematic-viscosity-d_412.html</ref> | + | #Define viscosity. Viscosity measures a liquid’s resistance to flow.<ref name="rf1"> http://physics.info/viscosity/</ref> A fluid with high viscosity flows very slowly, like honey. A fluid with low viscosity flows quickly, like water. The unit for viscosity is a pascal second (Pa s).<ref name="rf2">http://www.engineeringtoolbox.com/dynamic-absolute-kinematic-viscosity-d_412.html</ref> |
| − | #Define the equation for viscosity. This experiment will take measurements of a sphere and its passage through liquid to calculate viscosity. The equation for viscosity is '' [2(p<sub>s</sub>-p<sub>l</sub>)ga<sup>2</sup>]/9v'' where ''p<sub>s</sub>'' is the density of the sphere, p<sub>l</sub> is the density of the liquid, ''g'' is acceleration due to gravity, ''a'' is the radius of the sphere, and ''v'' is the velocity of the sphere.<ref>http://www.spacegrant.hawaii.edu/class_acts/Viscosity.html</ref> | + | #Define the equation for viscosity. This experiment will take measurements of a sphere and its passage through liquid to calculate viscosity. The equation for viscosity is '' [2(p<sub>s</sub>-p<sub>l</sub>)ga<sup>2</sup>]/9v'' where ''p<sub>s</sub>'' is the density of the sphere, p<sub>l</sub> is the density of the liquid, ''g'' is acceleration due to gravity, ''a'' is the radius of the sphere, and ''v'' is the velocity of the sphere.<ref name="rf3">http://www.spacegrant.hawaii.edu/class_acts/Viscosity.html</ref> |
| − | #Understand the variables in the viscosity equation. Density is mass per unit volume of an object and is designated with a ''p''. In this equation you need to measure the density of both the sphere, ''p<sub>s</sub>'', and the liquid, ''p<sub>l</sub>'', it is passing through. The radius of the sphere, ''a'', can be found by measuring the circumference of the sphere and dividing that by 2π. The acceleration due to gravity, ''g'', is a constant dependent on the atmosphere of the planet you’re on. In this case, you are on earth so ''g'' is 9.8m/s<sup>2</sup>.<ref>http://www.physicsclassroom.com/class/1DKin/Lesson-5/Acceleration-of-Gravity</ref> The velocity of the sphere, ''v'', is calculated during the experiment and is the time it takes an object to travel a specific distance in meters per second (m/s). | + | #Understand the variables in the viscosity equation. Density is mass per unit volume of an object and is designated with a ''p''. In this equation you need to measure the density of both the sphere, ''p<sub>s</sub>'', and the liquid, ''p<sub>l</sub>'', it is passing through. The radius of the sphere, ''a'', can be found by measuring the circumference of the sphere and dividing that by 2π. The acceleration due to gravity, ''g'', is a constant dependent on the atmosphere of the planet you’re on. In this case, you are on earth so ''g'' is 9.8m/s<sup>2</sup>.<ref name="rf4">http://www.physicsclassroom.com/class/1DKin/Lesson-5/Acceleration-of-Gravity</ref> The velocity of the sphere, ''v'', is calculated during the experiment and is the time it takes an object to travel a specific distance in meters per second (m/s). |
=== Measuring Viscosity === | === Measuring Viscosity === | ||
| − | #Gather the necessary materials for the experiment. To calculate viscosity of a liquid, you will need a sphere, a graduated cylinder, a ruler, a stopwatch, the liquid in question, a scale, and a calculator.<ref>https://www.teachengineering.org/view_activity.php?url=collection/cub_/activities/cub_surg/cub_surg_lesson03_activity1.xml</ref> This experiment has many steps, but when followed correctly, they will allow you to calculate the viscosity of any liquid. | + | #Gather the necessary materials for the experiment. To calculate viscosity of a liquid, you will need a sphere, a graduated cylinder, a ruler, a stopwatch, the liquid in question, a scale, and a calculator.<ref name="rf5">https://www.teachengineering.org/view_activity.php?url=collection/cub_/activities/cub_surg/cub_surg_lesson03_activity1.xml</ref> This experiment has many steps, but when followed correctly, they will allow you to calculate the viscosity of any liquid. |
#* The sphere can be a small marble or steel ball. Make sure its diameter is no greater than half the diameter of the graduate cylinder so it can easily be dropped into the cylinder. | #* The sphere can be a small marble or steel ball. Make sure its diameter is no greater than half the diameter of the graduate cylinder so it can easily be dropped into the cylinder. | ||
#* A graduated cylinder is a plastic container that has graded markings on the side that allow you to measure volume. | #* A graduated cylinder is a plastic container that has graded markings on the side that allow you to measure volume. | ||
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#Calculate the velocity of the sphere. Velocity is a measurement of distance traveled over elapsed time to travel that distance. The formula for velocity is <math>v=d/t</math> where ''v'' is velocity, ''d'' is distance traveled, and ''t'' is time. | #Calculate the velocity of the sphere. Velocity is a measurement of distance traveled over elapsed time to travel that distance. The formula for velocity is <math>v=d/t</math> where ''v'' is velocity, ''d'' is distance traveled, and ''t'' is time. | ||
#* Using your measurements, plug them into the equation <math>v=d/t</math> to find the velocity of the sphere. | #* Using your measurements, plug them into the equation <math>v=d/t</math> to find the velocity of the sphere. | ||
| − | #Calculate the viscosity of the liquid. Plug the information you have obtained into the formula for viscosity: ''viscosity = [2(p<sub>s</sub>-p<sub>l</sub>)ga<sup>2</sup>]/9v'' where ''p<sub>s</sub>'' is the density of the sphere, p<sub>l</sub> is the density of the liquid, ''g'' is acceleration due to gravity (a fixed value of 9.8 m/s<sup>2</sup>), ''a'' is the radius of the sphere, and ''v'' is the velocity of the sphere.<ref | + | #Calculate the viscosity of the liquid. Plug the information you have obtained into the formula for viscosity: ''viscosity = [2(p<sub>s</sub>-p<sub>l</sub>)ga<sup>2</sup>]/9v'' where ''p<sub>s</sub>'' is the density of the sphere, p<sub>l</sub> is the density of the liquid, ''g'' is acceleration due to gravity (a fixed value of 9.8 m/s<sup>2</sup>), ''a'' is the radius of the sphere, and ''v'' is the velocity of the sphere.<ref name="rf3" /> |
#* For example, let’s say the density of your fluid is 1.4 g/mL, the density of your sphere is 5 g/mL, the radius of the sphere is 0.002 m, and the velocity of the sphere is 0.05 m/s. | #* For example, let’s say the density of your fluid is 1.4 g/mL, the density of your sphere is 5 g/mL, the radius of the sphere is 0.002 m, and the velocity of the sphere is 0.05 m/s. | ||
#* Plugging into the equation: viscosity = [2(5 – 1.4)(9.8)(0.002)]/(9 x 0.05) = 0.314 Pa s | #* Plugging into the equation: viscosity = [2(5 – 1.4)(9.8)(0.002)]/(9 x 0.05) = 0.314 Pa s | ||
