1. Linear Thermal Expansion

2. Normal Solids Ex. Glass jar too tight, hot water over lid. L – length T – temp. Length and temp. is directly proportional.

3. Thermal Expansion Linear expansion – increase in any one dimension of a solid, linear is the expansion occurring along a line. Change in length is proportional to both (initial) L and change in Temp. Proportionality constant α(alpha), is called the coefficient of linear expansion.

4. Thermal Expansion Coefficient of linear expansion ___ has the unit of _____. Value of the ____ depends on the nature of the material.

5. Coefficients of Thermal Expansion for Solids and Liquids

6. Expansion Joint

7. Usefulness Anti-scalding device: shuts off the flow of water when it becomes too hot, Higher temp expands the actuator spring and pushes the plunger forward, shutting off the flow.

8. Homework Problem 5. If a 42 m steel footbridge experiences extreme temperatures between -12°C and 40°C, what is the range in size of this bridge if it measures exactly 42m at 22°C? (Steel has a coefficient of linear expansion of 1.1x10 -5 /°C)

9. Calculate Length for each set of values L 1 =L(1+α∆T 1 ) T 1 = -12-22=-34 42(1+ 1.1x10 -5 (-34))=41.9843 m L 2 =L(1+ α∆T 2 ) T 2 =40-22=18 42(1+ 1.1x10 -5 (18))=42.0083 ∆L=L 2 -L 1 42.0083-41.9843=.024024m