Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Chapter 6 Physical Principles of Respiratory Care

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 2 Learning Objectives  Describe the properties that characterize the three states of matter.  Describe how heat transfer occurs among substances.  Identify the three common temperature scales and explain how to use them.  Describe how substances undergo change of state.

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 3 Learning Objectives (cont.)  Identify the factors that influence the vaporization of water.  Describe how water vapor capacity, absolute humidity, and relative humidity are related.  Describe how to predict gas behavior under changing conditions, including at extremes of temperature and pressure.  Describe the principles that govern the flow of fluids.

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 4  Energy matter possesses = internal energy  Atoms of all matter at ordinary temperatures are in constant motion  Two major types of internal energy:  Potential energy Energy of position (attractive forces between molecules)  Weak in gas state  Makes up most of internal energy in solids & liquids  Kinetic energy Energy of motion  Makes up most of gases internal energy  All matter has some kinetic energy Internal Energy of Matter

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 5 States of Matter  Solids, Liquids, Gases  Solids  Have high degree of internal order  Fixed volume and shape  Strong mutual attractive force between atoms  Molecules have the shortest distance to travel before collision This motion referred to as a “jiggle”

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 6 States of Matter (cont.)  Liquids  Have fixed volume, but adapt to shape of their container  Atoms exhibit less degree of mutual attraction compared w/ solids Shape is determined by numerous internal & external forces  Gases  No fixed volume or shape; weak attractive forces  Gas molecules exhibit rapid, random motion w/ frequent collisions

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. States of Matter (cont.)  Plasma-  Referred to as fourth state of matter  Combination of: Neutral atoms Free electrons Atomic nuclei  Can react to electromagnetic forces & flow freely like liquid or gas  Not known to be relevant to practice of respiratory care 7

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 4 States of Matter 8

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 9 Heat Transfer & First Law of Thermodynamics  Thermodynamics can refer to 2 subjects:  Science studying the properties of matter at various temperatures  Kinetics, (speed) of reactions of matter at various temperatures  Energy can be neither created nor destroyed  Energy gain by substance = energy lost by surroundings

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Heat Transfer & First Law of Thermodynamics  Heat transfer  When two objects of different temperature coexist, heat will move from hotter to cooler object until both are equal  Example of transitioning from higher to lower state of order  Thermal Conductivity  Measure to quantify heat transfer between objects  Metals have high level 10

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 11 Heat Transfer & First Law of Thermodynamics  Heat transfer can occur in 4 ways:  Conduction  Main method of heat transfer in solids Via direct contact between molecules  Convection  Mixing of fluid molecules at different temperatures Transfers heat in liquids & gases (e.g., forced air heating in homes-fluid movements carry heat)  Radiation  Occurs w/out direct contact between two substances  Evaporation/condensation  Form of vaporization, change of state from liquid to gas, or gas to liquid

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 12 What is radiation heat transfer? A.a heat transfer that occurs without direct physical contact B.the mixing of fluid molecules at different temperatures C.the change of state from liquid to gas D.the loss of heat altogether

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Laws of Thermodynamics  3 physical principles describe how energy is handled & transferred: 1. Conservation of Energy  Energy cannot be created or destroyed 2. Thermodynamic Equilibrium  Given time all systems will achieve lowest possible energy state (entropy) 3. Impossibility of Achieving Absolute Zero (statistical law )  At absolute zero all processes cease & entropy is at minimum 13

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 14 The second Law of Thermodynamics called, “Conservation of Energy” is described as: A.given time, all systems will achieve the lowest possible energy state B.the lowest possible temperature that can be achieved C.that energy cannot be created, nor destroyed D.The lowest amount of entropy

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.  Two interrelated terms are significant:  Entropy  Amount of energy in system not available for work  Lowest amount of organization system can achieve (chaos)  Enthalpy  Total measure of energy in system  a.k.a., order of system 15 Internal Energy & Temperature

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Internal Energy & Temperature (cont.)  Temperature  Measurement of heat (collision of molecules)  Gas temperature is directly proportional to it’s kinetic energy; Closely related to kinetic energy Most of its internal energy spent keeping molecules in motion 16

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 17  Absolute zero  Concept  Lowest possible temperature that can be achieved  Temperature = no kinetic energy  Molecules cease to vibrate; object has no measurable heat  Scientists have not actually achieved it As stated by third law of thermodynamics Internal Energy & Temperature (cont.)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Internal Energy & Temperature (cont.)  Temperature Scales  Fahrenheit (F) & Celsius (C) scales based on property of water 0° C is freezing point of water - 273° C = kinetic molecular activity stops = 0° K  Kelvin scale (° K ) based on molecular motion Used by SI (Systeme Internationale) units Zero point = to absolute zero 18

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Internal Energy & Temperature (cont.)  Conversions:  ° K = ° C  ° C = 5/9 (° F – 32)  ° F = 9/5 °C

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 20 Change of State  Liquid-solid phase changes (melting & freezing)  Melting = changeover from solid to liquid state  Melting point = temperature at which melting occurs  Freezing = opposite of melting  Freezing point = temperature at which substances freeze; same as its melting point  Sublimation = transition from solid to vapor w/out becoming liquid as an intermediary form Occurs because vapor pressure is low enough (e.g., dry ice)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 21

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 22

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 23 Which of the following describes Sublimation? A.when water enters the atmosphere at a temperature below its boiling point B.heating a liquid to a temperature at which its vapor pressure equals atmospheric pressure C.phase transition from a solid to a vapor without becoming a liquid D.a force exerted by like molecules at a liquid’s surface

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 24 Change of State (cont.)  Properties of liquids  Pressure  depends on height & weight density  Buoyancy  occurs because pressure below submerged object always exceeds pressure above Gases also exert buoyant forces Helps keep solid particles suspended in gases (aerosols)  Specific Gravity  Ratio of density of one fluid when compared with density of another reference substance (typically, water)  Viscosity  Force opposing fluid’s flow Blood has viscosity five times greater than water

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 25

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 26 What is viscosity? A.the energy created or destroyed when changing between states of matter B. the temperature at which a substance freezes C.the force opposing a fluid’s flow D.changeover from the solid to liquid state

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 27

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 28

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 29 Change of State (cont.)  Fluid’s viscosity is directly proportional to cohesive forces between its molecules  The stronger the cohesive forces, the greater the fluid viscosity  Heart must use more energy when blood viscosity increases, as occurs in polycythemia (increase in red blood cell concentration)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.)  Cohesion & adhesion  Attractive force between like molecules = cohesion  Attractive force between unlike molecules = adhesion  Surface tension  Force exerted by like molecules at liquid’s surface (why bubbles retain spherical shape) 30

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 31

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 32

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 33

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 34

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 35 A force exerted by like molecules at a liquid’s surface defined as: A.the energy created or destroyed when changing between states of matter B.the temperature at which a substance freezes C.the force opposing a fluid’s flow D.changeover from the solid to liquid state

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 36 Change of State (cont.)  Liquid to vapor phase changes (vaporization)  2 types of vaporization  Boiling (point)  heating liquid to temperature at which its vapor pressure exceeds atmospheric pressure Boiling point of most liquefied gases is very low  Liquid oxygen boils at -183°C  Evaporation  when liquid changes into gas at temperature below its boiling point Water enters atmosphere via evaporation when at temperature lower than its boiling point (water vapor) Molecular water exerts pressure called water vapor pressure Temperature influences evaporation most The warmer the air, the more vapor it can hold

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 37

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 38

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 39 Change of State (cont.)  Absolute Humidity  a.k.a  water vapor content  Actual amount (or weight) of water vapor in gas  Measured in mg/L  Varies w/ temperature & pressure  Air that is fully saturated w/ water vapor has absolute humidity of 43.8 mg/L at 37°C, 760 mm Hg, & water vapor pressure of 47 mm Hg  Relative humidity  %RH = Content (Absolute Humidity)/Saturated Capacity x 100

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 40 Change of State (cont.)  Relative humidity (RH)  When gas is not fully saturated  Water vapor content can be expressed in relative terms  Ratio of its actual water vapor content to its saturated capacity at given temperature  %RH = Content (Absolute Humidity)/Saturated Capacity x 100  Condensation  up slight cooling of gas causes its water vapor to turn back into liquid state  Temperature at which this happens = dew point  100% RH still exists

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 41 Change of State (cont.)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Change of State (cont.) 42

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 43 Properties of Gases  Kinetic activity of gases  Gas molecules travel at high speeds in random fashion w/ frequent collisions  Velocity of gas molecules is directly proportional to its temperature  Molar volume & gas density  Ideal molar volume of any gas = 22.4 L at standard temperature & pressure  Density is ratio of gas’s mass to its volume

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 44 Properties of Gases (cont.)  Gaseous diffusion  movement of molecules from areas of high concentration to areas of lower concentration  Gas pressure  All gases exert pressure  Gas pressure in a liquid is known as gas “tension”  Atmospheric pressure is measured with a barometer

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 45 Properties of Gases (cont.) Components of a mercury barometer

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Properties of Gases (cont.) 46

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Properties of Gases (cont.) 47

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Properties of Gases (cont.) 48

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 49 Properties of Gases (cont.)  Gas pressure (cont.)  Partial pressure = pressure exerted by single gas in gas mixture  Dalton’s law  partial pressure of gas in mixture is proportional to its percentage in mixture  Solubility of gases in liquids (Henry’s law)  Volume of gas dissolved in a liquid is a function of its solubility coefficient & its partial pressure

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 50 Gas Behavior Under Changing Conditions  Gas laws  Boyle’s law  volume of gas varies inversely w/ its pressure  Charles’ law  volume of gas varies directly w/ its temperature

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 51 Gas Behavior Under Changing Conditions ● Gas laws (cont.)  Gay-Lussac’s law  pressure exerted by gas varies directly with its absolute temperature  Combined gas law  interaction of gas laws mentioned above

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Gas Behavior Under Changing Conditions 52

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 53 Fluid Dynamics  Study of fluids in motion = hydrodynamics  Pressure exerted by liquid in motion depends on nature of flow itself  Progressive decrease in fluid pressure occurs as fluid flows through tube due to resistance

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 54 Fluid Dynamics (cont.)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 55 Fluid Dynamics (cont.)  Patterns of flow  Laminar flow  fluid moving in discrete cylindrical layers or streamlines Poiseuille’s law  predicts pressure required to produce given flow using ΔP = 8nl V./ πr 4  Turbulent flow  loss of regular streamlines; fluid molecules form irregular eddy currents in chaotic pattern is predicted by using Reynold`s number (N R ) N R = v d2r / h

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 56 What does Poiseuille’s law predict? A.fluid moving in discrete cylindrical layers or streamlines B.the pressure required to produce a given flow C.the amount of dead space in a cylinder D.the pressure exerted by a liquid in motion

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 57 Fluid Dynamics (cont.)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Fluid Dynamics (cont.) 58

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 59 Fluid Dynamics (cont.) The Bernoulli effect  Fluid passing through tube that meets constriction experiences significant pressure drop  Fluid that flows through constriction increases its velocity while lateral wall pressure decreases

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 60 Fluid Dynamics (cont.) Fluid entrainment  Velocity of fluid (gas) can increase greatly at point of constriction  Causing lateral pressure to fall below atmospheric pressure  If open tube is placed distal to constriction, another fluid can be pulled into primary flow stream (fluid entrainment)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Fluid Dynamics (cont.) 61

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Fluid Dynamics (cont.) 62

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Fluid Dynamics (cont.) 63

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 64 Fluid Dynamics (cont.)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 65 Fluid Dynamics (cont.) Venturi & Pitot tubes  Venturi tube is modified entrainment device It widens just after its jet or nozzle Helps restore fluid pressure back toward prejet levels  Pitot tube (modified Venturi Tube) lessens effect of downstream pressure on fluid entrainment

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Fluid Dynamics (cont.) 66

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 67 Fluid Dynamics (cont.)

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 68 Fluid Dynamics (cont.) Fluidics & Coanda effect  Fluidics is branch of engineering applying hydrodynamics principles in flow circuits  Coanda effect (wall attachment) is observed when fluid flows through small orifice w/ properly contoured downstream surfaces

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 69 Fluid Dynamics (cont.)