Brian Stanley 2 November 2012 Keep the Heat/Thermodynamics

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

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.

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

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

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.)

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

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

Sample Questions What is 56 o C 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 0 o C? 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?

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

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

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

Testing the Device Competition and Testing: Temperature (60-90 o C), 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

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

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

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!

Questions?