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Keep the Heat a recycled event October 2011
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The object is to construct a device that is able to retain heat. Students will also be tested on thermodynamic concepts.
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Students must wear appropriate eye protection. Devices will be impounded.
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Parameters Students MUST bring: -their own insulating device -2 identical 250 ml Pyrex beakers -eye protection -Plots (known by normal people as graphs) -Writing utensils They also MAY bring -notes (must be 3-hole punched in a binder) -parts and supplies -calculator
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Supplied by Supervisor -hot water -Devices for transferring measured volumes of water to team beakers. -thermometers or probes
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Plots (Graphs!!??) Prior to competition students must test their device. Data collected must be displayed on up to 4 graphs (may be all in 1) Data should show the relationship between elapsed cooling time and ending water temperature. Variables should include amount of water and starting water temperature
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More on Plots May be computer generated or handwritten. Must be properly labeled. May be required to submit prior to competition Must have a duplicate set to use during competition. Students may be asked about their data and how they use their plots.
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Impounding Teams must impound -their device -parts and supplies (beakers; tools; notes; plots) -appeals will not be processed after the device is removed from competition. -all parts of the device must be approximately room temperature at impound.
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Eye Protection Must be worn during set-up and loading of their device. If time allows they may be given the chance to obtain eye protection. If this is not possible they may not compete in Part 1
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Construction Materials Only allowable materials -wood; paper; cardboard; natural fibers; organic granular material; aluminum foil Fastening materials may be: -tape; glue; screws; bolts; nuts; nails; string Fastening materials are only to be used for securing the components together.
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Prohibited Materials -foam (plastic; metal; expandable glue -plastic -bubble wrap -glass -commercial insulation
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The Device Must allow for the easy insertion and removal of a 250 ml beaker. Must accommodate the insertion and removal of a thermometer via a hole 1.5 cm in diameter directly above the beaker and will remain open during the competition. The top of the hole should be less than 5 cm above the lip of the beaker.
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Inspection Devices will be inspected to look for energy sources such as electrical components; battery powered heaters; chemical reactions. At the end teams must disassemble their devices to verify compliance with all rules.
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The Competition After Impound: -the temperature of the source water will be announced -the volume of the water to be used will be given -the cooling time will be announced -the ambient room temperature will be announced.
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Competition Teams will have 5 minutes to set up their devices at the start of competition. Water will be given to teams in a staggered sequence. Both beakers will be filled with the same amount of water. (one inside device and the other next to it.) Supervisors will record the time that the team received their water.
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Students Must use their graphs to calculate the temperature of the water They must supply the supervisor with their estimate at the end of the cooling time prior to the supervisor measuring the actual temperature.
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The Cooling Time At the end of the cooling period the supervisor will record the temperature in each beaker. Thermometers may be left in for the full time or may be reused for each station after necessary measures are taken to make sure all devices receive the exact same treatment. This will be announced prior to impound
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Written Test (50 pts) -Each team will be given the same amount of time to compete after all devices have been loaded. -Topics include temperature conversions; definition of heat units; thermal conductivity; heat capacity; specific heat; the laws of thermodynamics; the history of thermodynamics and thermodynamic processes
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Scoring High score wins All calculations are to be done in Celsius. Ranking will be done in two tiers -the highest are those with no violations of rules - the other group includes teams with any violation.
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Scoring of Graphs 10 points total -2 for proper labeling -2 for appropriate title of graph and axes -2 for appropriate units and axis labels -1 for each data plot on a graph (up to 4)
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Final Score Sum of four components Test score - 50 points Graph score - 10 points Heat Score -up to 50 points Prediction Score - up to 25 points
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Score Heat Retention Score Internal Beaker temperature External Beaker temperature 1 () X 50 55.8° 38° 1 )( x50=(1.55 - 1) x 50 = 22.5
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Score Prediction Score Final Int temp - Predicted Int temp Final Int. temperature () X 25 55.8° -49° 1 )( x25=(1- 0.12) x 25 = 22 1 55.8°
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Final Score Add all components together Test Score (50)40 Graph Score (10)10 Heat Retention Score (50)22.5 Prediction Score (25)22 Total out of possibe 135 90.5
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Written Test Worth 50 Points Entirely on thermodynamics - not scary - just a big word for heat. Don’t let your students be beaten by vocabulary. Have them build a binder with everything they should know - especially vocabulary.
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Written Test Temperature Conversions - use a chart for heaven’s sake. Heat Units calorie joule Thermal conductivity Heat Capacity Specific Heat Laws of Thermodynamics History of Thermodynamics Thermodynamic Processes
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Simply Put States of Matter Changes in State Heat transfer Specific Heat Q = mC∆t Thermometer scales Heat vs temperature Calorimeter Units
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More The First law of Thermodynamic is merely the law of Conservation of energy The Second states the heat cannot be transferred from a colder to a hotter body and that the entropy of an energy system increases with time. (chaos) Perfect order in the Universe occurred the second after the Big Bang when matter; energy and forces were most organized.
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And The Third law states that if all the thermal motion of an energy system could be removed that a state called absolute zero could be attained. http://www.physicalgeography.net/funda mentals/6e.html
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A Brief History of thermodynamics www.sussex.ac.uk/chemistry/.../a_thermodyn amics_history.pdfwww.sussex.ac.uk/chemistry/.../a_thermodyn amics_history.pdf Joule Gas laws Kinetic Theory Heat Transfer Laws of Thermodynamics Wikipedia History of thermodynamics
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Thermodynamic Processes www.allianceforwaterefficiency.org/.../E BMUD_WaterSmart_Guide_...www.allianceforwaterefficiency.org/.../E BMUD_WaterSmart_Guide_ Cooling towers Boilers and heating elements –Steam vs hot water
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Resources http://www.engineeringtoolbox.com/heat -work-energy-d_292.htmlhttp://www.engineeringtoolbox.com/heat -work-energy-d_292.html The Physics Classroom Phun Physics! U of Virginia http://physics.about.com/od/thermodyna mics/p/thermodynamics.htm
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