Searle's bar method
Searle's bar method is an experimental procedure to measure thermal conductivity of material. A bar of material is being heated by steam on one side and the other side cooled down by water while the length of the bar is thermally insulated. Then the heat ΔQ propagating through the bar in a time interval of Δt is given by
where
and the heat ΔQ absorbed by water in a time interval of Δt is:
where
Assuming perfect insulation and no energy loss, then
which leads to
