1. ThermalExpansionLinear and Volume

2. Objectives Define thermal expansion Identify the factors affecting thermalexpansion Solve sample problems involvinglinear expansion and volumeexpansion Cite everyday applications of theconcepts 3. Thermal Expansion Change in the dimension(s) ofa substance due to change intemperature 4. Factors affecting THERMALEXPANSION 5. Temperature Higher change intemperature, the higher theexpansion T for the symbol 6. Kind of Material Quantified by a constant valuefor coefficient of thermalexpansion for some materials The higher the coefficient, thehigher the expansion Symbol used - 7. Original Dimension Greater original dimension,greater the expansion. L for linear A for area V for volume 8. L = L0TChange in Coefficient of Originaldimension expansionlength Change in temperature 9. Types ofEXPANSION 10. Linear Expansion- the expansion in length of solid bodies onheatingL = L0T L0 L 11. Coefficients ofThermal Expansionfor Some materials 12. LINEARMATERIAL COEFFICIENT GLASS 8.5MERCURY 26ALUMINUM24COPPER17Example: BRASS19IRON 11.1 = 12 X 10-6 1/K PLATINUM9 GOLD 14 SILVER 18 STEEL11.0 ~ 13.0CONCRETE12 RUBBER 77 13. Opening a tight Jar lid 14. Volume Expansion- sometimes called the cubic expansion L = 3L0TorV0L = L0T orV V = V0T 15. Exercises 16. 1. During winter, why is itimportant to protect water pipes? 17. 2. Why is itadvisable to allowtelephone lines tosag when stringingthem betweenpokes in summer? 18. 3. What is the change in length ofa metal rod with an initial lengthof 2 meters, a coefficient ofthermal expansion 0.00002 /K anda temperature change of 20 K? 19. 4. Suppose you have a 0.05 Lcontainer made of glass that is at283 K. You raised its temperatureto 303 K. By how much will itsvolume increase? (glass = 25.5x10-6 1/K) 20. 5. A steel rail is 24.4mlong. How much does itexpand during a daywhen the lowtemperature is 291 Kand high temperature is306 K? (Steel = 12 x10 1/K) -6 21. 6. The length of a brass bar is 150cm at 40 C. What will be its lengthat 100 C?( = 19 x 10-6/K) 22. 7. An aluminum flag pole is20.0 m tall on a -15 C wintersday. How much higher will theflag fly from the pole on a hot42 C summer day? 23. 8. What amount of change intemperature did a 0.25 kg coppermetal undergo when it is initially5.0 m long and expanded by0.00002 m? 24. 9. A glass flask whose volume is 1000.0cm 3 at 0.0 C is completely filled withmercury at this temperature. Whenflask and mercury are warmed to 80.0 C, 12.5 cm3 of mercury overflow.Compute the coefficient of volumeexpansion of the glass.