This document discusses heat conduction through three main points: 1. It introduces the three types of heat transfer and defines heat conduction as heat transferring from a hot object to a colder one. 2. It presents the theory of heat conduction, including the formula for heat current. 3. It describes an experiment measuring the thermal conductivity of copper and brass rods, finding that brass has a lower thermal conductivity than copper.

1. Heat Conduction
Group A-2

2. Heat Conduction - Introduction
• Three types of heat transfer:
– Radiation
– Convection
– Conduction
• Heat always transfers from a hot object to a
colder one.

3. Heat Conduction – Theory
• Introduction
– Heat current
• Symbol: H
• SI Units: W/mK
• Formula:
• At steady state, the heat current within an object,
regardless of composition, is uniform all-throughout

4. Heat Conduction – Theory
Source: [1]

5. Heat Conduction - Experiment
• Objectives
– Understand the concept of thermal conductivity
– Determine the thermal conductivity of brass

6. Heat Conduction - Experiment
• Procedure – What to do?
– Insert metal rods through rubber tubing
– Place exposed copper end to steam
– Place exposed brass end to ice

7. Heat Conduction - Experiment
• Procedure – What to measure?
– Measure diameter of rods
– Measure length of rods
– Measure temperature of steam, TH
– Measure temperature of ice, TC
– Measure temperature at junction, T

8. Heat Conduction - Experiment
• Results
• Diameter = 12.0 mm
• Length = 15.0 cm
• TH = 94 oC
• Tc = 73 oC
• T = 0 oC

9. Heat Conduction - Worksheet
• Results
Data Table 1. Heat conduction
Kexpt Ktheo
A (m2) L (m) TH(K) T(K) Tc(K) %error
(W/mK) (W/mK)
1.13
Copper 0.150 367 385
x10-4
346
1.13
Brass 0.150 273 111 109 2%
x10-4

10. Heat Conduction - Worksheet
• Calculations
–
–

11. Heat Conduction - Worksheet
• Answers to Questions
1. Based on your calculations, which metal has the
greater temperature drop? What does this result
say about the ability of the metal to conduct
heat?
2. Is your result in question 1 consistent with the
theoretical values of thermal conductivity of
copper and brass? Why or why not?

12. Heat Conduction - Worksheet
• Answers to Questions
3. What are the possible sources of error in the
experiment? In which direction do they affect
the measured values of thermal conductivity?

13. Heat Conduction
• Conclusion
– The thermal conductivity of an object is
dependent on its composition and dimensions
(Cross-sectional area and length).
– For two connected objects of the same dimension
connected to hot and cold reservoirs, the higher
the temperature drop, the lower the thermal
conductivity

14. Heat Conduction
• Conclusion
– Brass was experimentally found to have a thermal
conductivity of 111 W/mK
– Brass is less conductive thermally than copper.

15. Heat Conduction
• References
– [1]
Hugh D. Young, Roger A. Freedman, contributing
author A. Lewis Ford. "Figure 17.23 Steady-state heat
flow due to conduction in a uniform rod." Hugh D.
Young, Roger A. Freedman. Sears and Zemansky's
University Physics with Modern Physics. San Francisco:
Pearson Addison-Wesley, 1898-1975. 592.
– [2] Nagi91860. “Ace vs Aokiji – One Piece Episode 481”
Eiichiro Oda. One Piece. 1997.
http://www.youtube.com/watch?v=uvYWRpN2rz4

16. Heat Conduction