Heat Conductivity in Gases

In this experiment you will study the process of thermal conductivity by gas molecules.

Preparation

Answer in writing:

  1. What are the objectives of this experiment?
  2. Heat transfer mechanisms:
    1. Explain the mechanisms of heat transfer in gases: conduction, convection and radiation. Give an example for each mechanism.
    2. What is the difference between conduction and convection?
    3. Under what terms can heat transfer by radiation and convection be neglected? What can you do during the experiment to minimize effects of radiation and convection?
  3. What values will you be measuring? How will you use them to determine R0 and the thermal conductivity coefficient? Explain in detail and give mathematical formulas.
  4. Estimate the threshold pressure for Nitrogen gas below which the heat conductivity is dependent on pressure, in our system. Explain why this threshold exists and why it is dependent on pressure.
  5. What properties of the gases affect their heat conductivity and how? Present the thermal conductivity coefficients of the various gases in the experiment in ascending order, and explain how the properties you mentioned cause the difference.

Prepare in advance:

Find the values of R0 of the wire and K reported in the literature for each gas.

What you should know:

  1. How to assemble the electric circuit.
  2. What are the expected results and how they should be analyzed.