Heat and energy transfer E Energy off phase h change h off water Water cycle y Groundwater click here for 9 page to print Heat Calorie Amount of heat required q to raise the temperature of 1 gram of pure water 1o C Food Calories Calories are kilocalories Joule of calorie 1 cal 4 184 J Specific Heat Capacity Quantity of heat needed to change the temperature p of g given amount of a substance 1o C Water very Water very high specific heat capacity 1 calorie raises one gram of water 1 C 1 calorie raises one gram of rock 5o C Maritime areas more mild temperature than continental areas Laws of Thermodynamics 1 Conservation of energy and matter 2 Entropy is increased with conversion 3 No system can reach absolute zero C P Snow the British scientist and author has offered up p an easy and funny way to remember the Three Laws He says they can be translated as 1 You cannot win you can t get something for nothing because matter and energy are conserved 2 You Y cannott break b k even you cannott return t to t the th same energy state because entropy always increases 3 You cannot get out of the game because absolute zero is not attainable Heat Expansion Random motion causes substance to be bigger bi Liquids usually have greater heat expansion than solids Thermostats Th t t use diff differentt expansion i off different type of metals http www alaskarails org terminology questions html http demo physics uiuc edu LectDemo scripts demo descript idc DemoID 40 Water Expansion Unusual response to cooling g Contracts until reaching 4o C Expands slightly upon further cooling to 0o C Expands 9 upon freezing Water Molecule Bent Polar P l Water Expansion Molecule shape fit together closer in liquid Open structured crystal due to hydrogen bonding of polar molecules upon freezing Heat Transfer conduction Tile is a better conductor of heat than the wood floor Heat Transfer convection Currents from heater shown by y shadows Heat Transfer radiation Does not need material to transfer radiant energy gy Dark bodies absorb it better than light light colored colored ones Radiant Energy All objects bj t emit it th thermall energy Visible light above 500oC Re emit absorbed radiation at wavelength according to temperature Good absorbers are good g emitters Poor absorbers are poor emitters Heat Transfer Conduction Direct molecule interaction Transferring energy to next molecule Convection C ti Movement of fluid liquid or gas Radiation Through open space Electromagnetic radiation Water Energy of Phase Change Calorie energy gy to change g 1 g water 1 K or 1 oC Also need energy to change to different state of matter Energy of vaporization condensation 540 calories per gram of water 2256 J g Energy of melting freezing 80 calories per gram 334 J g Energy of phase change for water http hyperphysics phy astr gsu edu hbase thermo phase html Water Energy to melt ice Energy goes into breaking the bonds that are holding the molecules in fixed position with respect p to one another 80 calories per gram of ice that melts Temperature remains constant during this Water Heat of Fusion Heat added to ice causes the phase change g No change in temperature until all the ice is melted melted Heat taken up by water upon melting Heat released from water upon freezing 80 calories l i per gram off water t th thatt goes from frozen to liquid or liquid to frozen Water Heat of Vaporization Heat taken up by water upon vaporizing Heat added to water causes the phase change no change in temperature until all the water is vaporized vaporized Heat released from water upon condensing sometimes described as the heat of condensation 540 calories per gram of water that goes f from vapor to t liquid li id or liliquid id tto vapor In Class Activity In Class How much energy is transferred to the environment when one gram of steam at 100o C condenses to water at 100o C Energy off vaporization E i ti and d condensation d ti 540 calories gram of water In Class Activity In Class How much energy is transferred to the environment when one gram of boiling water at 100o C cools to 0o C Definition D fi iti off calorie l i h heatt required i d tto change h the temperature of 1 gram of water 1o C In Class Activity In Class How much energy is transferred to the environment i t when h one gram off water t att 0o C freezes to ice at 0o C Energy off melting E lti and d ffreezing i off water t 80 calories gram In Class Activity In Class How much energy is transferred to the environment when one gram of steam at 100o C cools l tto 0o C and d ffreezes tto become b iice Heat is released in this process Condense 1 g from steam to liquid 540 cal g x 1 g 540 cal released for condensation 100oC x 1 cal g x 1 g 100 cal released for cooling 80 cal g x 1 g 80 J to freeze Total these to get 720 calories are released Three phases h off water http www cdli ca CITE glaciers htm Atmosphere Evaporation Energy gy g goes into air Cools remaining water Condensation C d ti Energy goes from air to surface Warms local environment Water Cycle 86 of evaporation from sea surface 14 of atmospheric moisture from land as EVAPOTRANSPIRATION 78 8 of o precipitation p ec p tat o on o sea su surface ace 22 of water precipitated falls on land http meted com mesoprim mpradfog print htm Water Cycle Water Cycle Less that 3 of Earth s water is on land Over of that is in glacial ice Most of the rest is stored as groundwater some groundwater is saline Water Distribution Groundwater Precipitation infiltrates Earth s surface Largest g reservoir of liquid q fresh water Drinking water source for half of U S Groundwater Surface water Water sources in Oregon http www deq state or us wq dwp dwp htm Groundwater Contributes to stream flow Universal Universal solvent solvent Dissolves some rock types Limestone CaCO3 Salts NaCl KCl Gypsum CaSO4 Groundwater Source First becomes soil moisture Plants use it Some evaporates directly Some sinks down Infiltration Groundwater is stored Groundwater Terms Zone of saturation Water table Zone of aeration Groundwater terms diagram Groundwater Storage Porosity of rock Spaces p between sand g grains Cracks in crystalline rock Dissolved cavities Permeability Allows water to move Interconnection of pore spaces Groundwater Storage Stored in AQUIFER Porous and p permeable rock Trapped by AQUITARD Impermeable I bl rock k Clay shale Groundwater Movement Very slowly Small openings p g High surface tension P Pressure forces f water t to t areas off lower l pressure Hydraulic gradient
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