Experiment 10: Determination of Heat Conduction
Objective
1. To obtain the thermal conductivity of brass and stainless steel
2. To obtain overall heat transfer coefficient along a composite bar
Introduction
First law of Thermodynamics states that energy can neither be created nor
destroyed; energy can only be transferred or changed from one form to another. Same goes to
heat transfer, it is governed by the first law of thermodynamics too. Heat can be transferred
from one place to another by three methods: conduction which happens in solids, convection
of fluids which may be liquid or gases, and radiation that can passes through the vacuum.
Heat transfer happens when there is a temperature gradient, which means heat will always
move from the higher to the lower temperature.
In this experiment, the light will be shed on heat conduction. The process of heat conduction
will be affected by the thermal conductivity of specimen, cross sectional area, temperature
gradient, and length of specimen. Temperature gradient is the physical quantity that draws the
direction and the rate of heat travel. Temperature flow from higher temperature point to lower
temperature point or it can be said as from higher kinetic energy to lower kinetic energy.
Thermal transfer stops after they reached thermal equilibrium. Cross-section and path of
travel both play a preponderant role in conduction. The greater the size and length of an
object, the more energy that’s required to heat it. And the greater the surface area that’s
exposed, the more heat is lost. Smaller objects with small cross-sections have minimal heat
loss. Physical properties determine which materials transfer heat better than others.
Figure:
Heat Conduction
