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Keep the Heat/Thermodynamics

Keep the Heat/Thermodynamics. Brian Stanley 2 November 2012. Overview. Thermodynamics Event Parameters Device Specifics Preparing for the Written Test What to Expect on Competition Day Questions. What is it?. Definition:

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Keep the Heat/Thermodynamics

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  1. Keep the Heat/Thermodynamics Brian Stanley 2 November 2012

  2. Overview • Thermodynamics • Event Parameters • Device Specifics • Preparing for the Written Test • What to Expect on Competition Day • Questions

  3. What is it? • Definition: • Thermodynamics is the study of thermal energy along with how it interacts with matter • Description: • Teams must construct an insulated device prior to the tournament that is designed to retain heat. Students must also complete a written test on thermodynamic concepts.

  4. Event Overview • Build a device • Specific materials are prohibited (see official rules) • Creativity is encouraged • Test the device • Starting temperature of water • Volume of water • Time of test • Room temperature effects? • Study for written test • Topics listed on rules sheet

  5. Device Specifics • Device MUST fit within 20 cm. cube (K.T.H.) or 15 cm. cube (Thermo) when fully assembled • 250 mL beaker must be easy to get to and remove • Once impounded, changes to the device CANNOT be made • No electrical devices, chemical reactions, other energy source • Must have a hole (1.5 cm. diam.) in top for thermometer

  6. Temperature Plots • Teams provide up to 4 plots that demonstrate the performance of the device • Scoring • 2 pts. if labeled with school and names • 2 pts. for appropriately labeled axes and title • 2 pts. for appropriate units • 1 pt. for each data plot on a graph or graphs turned in (up to 4 total pts.)

  7. Written Test • Topics: • Temperature conversion • Units of heat • Thermal conductivity • Heat capacity • Specific heat • Laws of thermodynamics • History/people of thermodynamics • Thermodynamic processes

  8. General Test/Study Tips • 3-ring binder permitted • No limit on size or content • Be practical • Organization is key • Limited time • Print pages • Organize by parent topic • Tabs are useful • Highlight specific equations and key terms/people • Books tend to be too complicated/specific

  9. Sample Questions • What is 56oC in: • Fahrenheit • Kelvin • Rankine • How many BTU’s are in one gram calorie? • What is the specific heat capacity of dry air in J/g-K at 0oC? • Who is considered to be the Father of Thermodynamics? • Who is the Kelvin temperature scale named after? • What is the relationship between Heat Capacity and Specific Heat?

  10. Sample Questions • Competition questions may be: • Multiple choice • Fill in the blank • Matching • Short answer • Intent is not to trick students, but to test their knowledge of basic thermodynamic principles • Practice solving these problems beforehand

  11. What to Expect • One hour for impound • Expect a line • Hint – arrive early to make life easier • Have everything you need organized in a plastic container • Students are responsible for: • Device • 2 identical 250 mL beakers • Eye protection (splash rated) • Plots • Writing utensils • Notes • Calculator

  12. What to Expect • Event supervisors will provide: • Hot water • Devices for transferring water to device • Thermometers • Students may bring thermometers, if desired • Stop watches • Miscellaneous

  13. Testing the Device • Competition and Testing: • Temperature (60-90oC), volume of water, and time (20-40 min.) is same for all teams • Announced after impound when all teams are in room • Teams given 5 min to setup/modify devices • Team must be ready to test when supervisor calls on them • Testing set up in staggered sequence • Division C teams have option of adding up to 50 mL of ice water

  14. Tips • NOT a performance building event! • Performance of device is only 25% of final score • Focus is on reliability and repeatability • Test, test, test and test some more! • Accuracy of predictions matters • Division C – If confident, go for the ice water bonus

  15. Tips for Building • For Performance • Make interior tight to limit convection heat transfer • Design for a pluggable hole • Use light materials with good insulation properties • Balsa wood, sawdust • For Reliability • Line interior of device in aluminum foil • Use sturdy materials • Think carefully about fastening materials together • Permanent is not always good • Devices must be easily disassembled for inspection

  16. What are the judges looking for? • Knowledge of rules • Knowledge of device • Do students know why materials were chosen? • Can students efficiently assemble device? • Creativity • Accuracy of temperature prediction • Confidence!

  17. Questions?

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