Thermometer • Mercury or alcohol-filled glass tube, used to measure temperature • Main principle: Liquids will change volume depending on its temperature
Manometer: a device for measuring pressure
Thermometers, Manometers, and Sphygmomanometers
Manometer • A simple manometer is a glass U tube filled with liquid • Pressure corresponds to fluid density and height and gravity
Everyday manometer
Water Manometer What can you say about the liquid in the tube?
Glass Manometer with Liquid Connected to gas source One end is open to the atmosphere and one is closed. Point A is at atmospheric pressure Point C is the pressure of the gas at the closed end of the tube
Glass Manometer Connected to gas source Point B has a pressure greater than atmospheric due to the weight above it (height h) The pressure at point B is equal to the pressure at point ______ Then…what can you say about the pressure exerted by the gas source? ?
Glass Manometer Connected to gas source The pressure exerted by the gas source at the trapped end of the tube is more than atmospheric pressure by the amount h
What’s Going On? Connected to gas source What can you conclude about the pressure at Point C?
Newton’s Third Law: Law of Conservation of Energy • Energy may not be created nor destroyed • The sum total of all the energies in a system (potential, kinetic, heat, light) is a constant
Example of Conservation of Energy: Pendulum
The sum of all energy in a system is constant Potential energy= m X g X h M = mass g = force of gravity h = height position of blue ball- Potential energy Kinetic energy = energy of motion Position of purple ball-______energy
PE + KE = 0 What makes the pendulum stop?
Bernoulli’s Equation P 1 What can you say about the flow of water through this tube?
Bernoulli’s Equation Energy per unit volume before= energy per unit volume after P 1
Bernoulli’s Equation: For fluids with a constant density, steady flow, and no friction
A Closer View of Bernoulli’s equation
How does Bernoulli’s equation relate to blood vessels?
Cross-sectional area vs velocity When blood vessel diameter decreases, velocity increases; arterial diameter is less than that of veins
Bibliography: “Animated Demonstration of Bernoulli’s Principle, < 10 July 2009 http: //home. earthlink. net/~mmc 1919/venturi. html> “Bernoulli’s Equation, ” 10 July 2009 <http: //www. princeton. edu/~asmits/Bicycle_web/Bernoulli. html> “Bernoulli Equation, ” The Engineering Toolbox, 14 July 2009 <http: //www. engineeringtoolbox. com/bernouilli-equationd_183. html> “Bernoulli’s Equation, ”< 14 July 2009, http: //www. grc. nasa. gov/WWW/K-12/airplane/bern. html > “Build your Own Manometer, ” The Science House-Flight, 15 July 2009 <www. science-house. org/student/bw/flight/manometer> “Cardiovascular Physiology Concepts, “ 15 July 2009 <http: //www. cvphysiology. com/Hemodynamics/H 013. htm> “The Law of Conservation of Energy, ” 15 July 2009 < http: //library. thinkquest. org/2745/data/lawce 1. htm> Loeschnig, Louis and Jack Gallagher, Chemistry Experiments, Sterling Publishing Company, I nc. , NY, 2005 ‘Manometers, ” July 2002 <http: //www. upscale. utoronto. ca/PVB/Harrison/Manometer. html> “Manometer or How Fast are we Going? , ”August, 2006 <http: //iflyez. com/manometer> “Pressure, “ 28 February, 2001<http: //neon. chem. uidaho. edu/~honors/111%Notes/pressure>
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