Which Liquid Has the Highest Viscosity?
In this project we will determine the viscosities of 5 separate liquids. The liquids we will test are corn syrup, honey, vegetable oil, milk, and water. We will find their viscosities by dropping a marble into each of these liquids and measuring the time it takes for it to reach the bottom. Before we conduct the experiment, we must first understand what viscosity is. “Viscosity is the quantity that describes a fluid's resistance to flow”.1 It is essentially fluid friction and transforms kinetic energy of motion into heat energy, just as friction (“the force between surfaces in contact that resists their relative tangential motion”) does between two solid bodies. All fluids express some amount of viscosity. An ideal fluid has no internal friction between the molecules, meaning that it is not viscous. The reciprocal of viscosity is fluidity (“the physical property of a substance that enables it to flow.”)2 Thus, fluids that are high in viscosity tend to flow slower while fluids that are low in viscosity tend to flow faster. Different liquids have different forces: the larger the intermolecular force, the more viscous it is and vice versa. We must also understand what terminal velocity and density are and how they relate to viscosity. “Terminal velocity is the constant velocity finally attained by a body moving through a fluid under gravity when there is no resultant force acting on it.” It has a direct relationship (“a relationship between two numbers or other variables where an increase or decrease in one variable causes the same change to occur in the second variable”) with viscosity. The more viscous a fluid is the slower a solid will fall through it. “Density is defined as the distribution of quantity per unit usually of space.” Viscosity and density are independent of each other. However, in this experiment the densities are needed in order to determine each
Citations: The Physics Hypertextbook. 2010 http://physics.info/viscosity/resources.shtml 2 "fluidity." Merriam-Webster Online Dictionary. 2010. Viscosity Teacher Page. Retrieved September 6, 2008 Viscosity.html Last edit date: 2008-12-05 09:00:00 Merriam-Webster Online Dictionary. 2010. Kristin Strong. Science Buddies. “Viscosity Teacher Page.” September 6, 2008 Edited by Peter Boretsky, Lockheed Martin http://www.investorwords.com/2594/inverse_relationship.html. 25 February 2010 Massey, B S (1983) Mechanics of Fluids, fifth edition, http://www.chemistrydaily.com/chemistry/Viscosity#Fluidity Pfitzner, J (1976), "Poiseuille and his law.", Anaesthesia 31 (2): 273–5, 1976 Mar, Linda McGraw (April 19, 2000). "Biodegradable Hydraulic Fluid Nears Market". USDA. http://www.ars.usda.gov/is/pr/2000/000419.htm. 2006-09-29. 2-12-10 William H Braun, Charles L.; Sergei N. Smirnov (1993). "Why is water blue?". J. Chem. Educ. 70 (8): 612. http://en.wikipedia.org/wiki/Water#Chemical_and_physical_properties 2-14-10 Bradburn, Greg “High Density, Low Viscosity”