Viscosity of blood.pdf

Viscosity of liquid Water and oil Viscosity of liquid Purpose : To determine the viscosity of the medium by using a small sphere falls with constant terminal velocity. Viscosity of liquid Apparatus : A long glass tube about 50 cm long closed at one end Oil Meter scale. Small sphere. Rubber bands. Ma...

Viscosity of liquid Water and oil Viscosity of liquid Purpose : To determine the viscosity of the medium by using a small sphere falls with constant terminal velocity. Viscosity of liquid Apparatus : A long glass tube about 50 cm long closed at one end Oil Meter scale. Small sphere. Rubber bands. Magnet. Stop watch. Viscosity of liquid Theory: The Viscosity: viscosity is the quantity that describes a fluid's resistance to flow. Fluids resist the relative motion of immersed objects through them. The mathematical expression describing the viscous drag force on a sphere falling through a liquid was determined by the law Stokes R α ηrv Viscosity of liquid R=6πηrv …………… (1) The formula for the buoyant force on a sphere is accredited Archimedes B = ρ g V displaced …………………….. (2) The formula for weight W = mg = ς g V object ………………... (3) Let's combine all these things together for a sphere falling in a fluid. Weight goes down, buoyancy goes up, drag goes up. After a while, the sphere will fall with constant velocity. When it does, all these forces cancel Viscosity of liquid B+R=W ρgV + 6πηrv = ς gV 6πηrv = (ς - ρ) gV But : ρ = density of liquid ς = density of sphere d= diameter of sphere v = velocity of sphere (slope) g = 980 cm/sec² slope = h/t r=d/2 and V= 𝟒 /𝟑 𝝅𝒓³ 𝛈 =𝐠 (𝛔− 𝛒) 𝐝𝟐/𝟏𝟖 𝐯……………… (1) Equation (1) use to deduce the viscosity ( η ) for liquid , where… Viscosity ofliquid liquid Viscosity of The SI unit of viscosity is the pascal second [Pa s], that N.s/m² or Kg/m.s. The most common unit of viscosity is the dyne. second per square centimeter [dyne s/cm²] , which is given the name poise [P] 1 pascal second = 10 pois h(cm) slope = h/t t (sec ) Viscosity of liquid Procedure : Adjust the distance between the rubber band. Record the distance (h) between them. ( about 30 cm ). Drop a sphere centrally down the jar & with stop-watch find the time it take to traverse the distance between the rubber band. Obtain two values of the time of fall. Repeat the experiment for different value of ( h ) & obtain two values of the time of fall for each new distance apart. Viscosity of liquid Result and Calculation : Plot a graph with values of (h) cm as ordinates against the corresponding values of t(sec) as abscissa. From the graph calculate the terminal velocity. Slope = h / t = velocity ( cm / sec ) Calculate the viscosity from equation (1) Distance between rubber bands h(cm) Time of fall t (sec) Viscosity of liquid Questions : What isisthe relation between viscosity and temperature. What the relation between viscosity and temperature ? Is the reaches it terminal velocity immediately after Is thesphere sphere reaches it terminal velocity immediately after dropping. ? dropping Is the of sphere effected on theon fallsthe velocity. Is thediameter diameter of sphere effected falls velocity ?