Thermal Expansion

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Thermal Expansion

Experiment No. 2

*Santos, Patricia Mary O.
Aquino, Junior Emil S.
Bautista, Jennina
Besana, Carra Sophiya
Lime, Jerricson

III-32 BSE General Science

July 02, 2012

Abstract
This experiment is done to determine the temperature coefficient of linear expansion of different materials. The different temperature coefficient is obtained through the use of an apparatus for measuring the linear expansion. The PASCO Thermal Expansion Apparatus was use to measure the thermal expansion to get the temperature coefficient. All metals which are used in the experiment all expanded due to the rising of the temperature. The temperature coefficient obtained from experiment is close to the actual or accepted temperature coefficient.

Introduction
The coefficient of thermal expansion (α) is defined as the fractional increase in the length per unit rise in temperature. It is a material property that is indicative of the extent to which a material expands upon heating. Different substances expand by different amounts. Over small temperature ranges, the thermal expansion of uniform linear objects is proportional to temperature change. Thermal expansion finds useful application in bimetallic strips for the construction of thermometers but can generate detrimental internal stress when a structural part is heated and kept at constant length.

Theory
Most materials expand when heated through a temperature range that does not change in phase. The added heat increases the vibration of the atoms in the material which increases the separation of atoms.

Suppose an object of length L undergoes a temperature change of magnitude ∆T. If ∆T is reasonably small, the change in length, ∆L, is generally proportional to L and ∆T. ∆L=αL0∆T, where α is the coefficient of linear expansion for the material.

The change in temperature determines the fractional change in length. Different substances would expand by different amounts. An expansion coefficient is...
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