Brian Stanley2 November 2012

Keep the Heat/Thermodynamics

OverviewThermodynamicsEvent ParametersDevice SpecificsPreparing for the Written TestWhat to Expect on Competition DayQuestions

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 OverviewBuild a device

Specific materials are prohibited (see official rules)

Creativity is encouragedTest the device

Starting temperature of waterVolume of waterTime of testRoom temperature effects?

Study for written testTopics listed on rules sheet

Device SpecificsDevice 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 PlotsTeams provide up to 4 plots that

demonstrate the performance of the deviceScoring

2 pts. if labeled with school and names2 pts. for appropriately labeled axes and title2 pts. for appropriate units1 pt. for each data plot on a graph or graphs

turned in (up to 4 total pts.)

Written TestTopics:

Temperature conversionUnits of heatThermal conductivityHeat capacitySpecific heatLaws of thermodynamicsHistory/people of thermodynamicsThermodynamic processes

General Test/Study Tips3-ring binder permitted

No limit on size or contentBe practical

Organization is keyLimited time

Print pagesOrganize by parent topicTabs are usefulHighlight specific equations and key

terms/peopleBooks tend to be too complicated/specific

Sample QuestionsWhat is 56oC in:

FahrenheitKelvinRankine

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?

Sample QuestionsCompetition questions may be:

Multiple choiceFill in the blankMatchingShort answer

Intent is not to trick students, but to test their knowledge of basic thermodynamic principles

Practice solving these problems beforehand

What to ExpectOne hour for impound

Expect a lineHint – arrive early to make life easier

Have everything you need organized in a plastic container

Students are responsible for:Device2 identical 250 mL beakersEye protection (splash rated)PlotsWriting utensilsNotesCalculator

What to ExpectEvent supervisors will provide:

Hot waterDevices for transferring water to deviceThermometers

Students may bring thermometers, if desiredStop watchesMiscellaneous

Testing the DeviceCompetition and Testing:

Temperature (60-90oC), volume of water, and time (20-40 min.) is same for all teamsAnnounced after impound when all teams are in

roomTeams given 5 min to setup/modify devicesTeam must be ready to test when supervisor

calls on themTesting set up in staggered sequenceDivision C teams have option of adding up to

50 mL of ice water

TipsNOT a performance building event!

Performance of device is only 25% of final score

Focus is on reliability and repeatabilityTest, test, test and test some more!

Accuracy of predictions matters

Division C – If confident, go for the ice water bonus

Tips for BuildingFor Performance

Make interior tight to limit convection heat transfer

Design for a pluggable hole

Use light materials with good insulation propertiesBalsa wood, sawdust

For ReliabilityLine interior of

device in aluminum foil

Use sturdy materialsThink carefully

about fastening materials togetherPermanent is not

always goodDevices must be easily

disassembled for inspection

What are the judges looking for?Knowledge of rulesKnowledge of device

Do students know why materials were chosen?

Can students efficiently assemble device?CreativityAccuracy of temperature predictionConfidence!

Questions?