CHAPTER 12 : THERMAL EXPANSIONS OF SOLIDS, LIQUIDS AND GASES
It is known from experience that matter in all three states solids, liquids and gases expands when heated.
The characteristics of expansion are considered in details as follows.
12.1 Solids
Solids are available in definite shapes of rods, laminas and blocks. Therefore the following three
coefficients can be defined.
Coefficient of Linear Expansion :
a
The change in length, per unit original length per
1^{0}C change in temperature, is called the coefficient
of linear expansion.
Note: 1) Expansions in surface area and volume are negligible.
2) a varies slightly over a range of temperatures, but the variation is negligibly small.
Coefficient of Superficial Expansion :
b
The change in surface area per unit original area per
1^{0} C change in temperature is called the coefficient
of superficial expansions.
Note: 1) Expansion in volume is negligible.
2) Same comment as for a
3) b @ 2 a
Coefficient of Cubical Expansion
The change in volume per unit original volume per
1^{0}C change in temperature is called coefficient of
cubical expansion.
Note: 1) Same comment for variation in
g as for a & b.
2) g @ 3a.
