# Keep the Heat/Thermodynamics

Mechanics

Oct 27, 2013 (4 years and 6 months ago)

73 views

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

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

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?