1. AP Physics B Temperature & Heat

2. What is Temperature? Temperature is a property that determines the direction of thermal energy transfer between two bodies in thermal contact. Temperature is a measure of how hot or cold something is. Thermometers are instruments designed to measure temperature. In order to do this, they take advantage of some property of matter that changes with temperature.

3. Conversions

4. The Common Temperature Scales Fahrenheit & Celsius Celsius & Fahrenheit

5. What is absolute zero? Absolute temperature is a measure of the average kinetic energy of the molecules of a substance.

6. Absolute Zero (0K)

7. Linear Thermal Expansion With a few exceptions, all substances – solids, liquids, & gases – expand when heated and contract when cooled. Different materials expand at rates. The construction of structures and devices must take this into consideration.

8. Thermal Expansion of Solids and Liquids A steel washer is heated Does the hole increase or decrease in size? Expansion occurs when an object is heated.

9. When the washer is heated The hole becomes larger Thermal Expansion of Solids and Liquids

10. Calculating Linear Thermal Expansion The extent to which something expands/contracts with temperature (  L) depends on:

11. LoLo LL  L  L o  T TT  L =  L o  T L = L o (1+  T) Coefficient of linear expansion L  L o =  L o  T Thermal Expansion of Solids and Liquids

12. Example The Eiffel Tower, constructed in 1889 by Alexandre Eiffel, is an impressive latticework structure made of iron. If the tower is 301 m high on a 22 ºC day, how much does its height decrease when the temperature cools to 0.0 ºC?  L =  L o  T -0.073m

13. Volume Thermal Expansion Since the length of an object changes with temperature, it follows that its area changes as well… Objects will expand in volume as well as in length Volume thermal expansion is analogous to linear thermal expansion

14. New Volume Initial Volume LoLo LoLo LoLo L o +  L Volume Expansion  L =  L o  T Thermal Expansion of Solids and Liquids

15. Coefficient of Volume Expansion Thermal Expansion of Solids and Liquids

16. Example A copper flask with volume of 150 cm 3 is filled to the brim with olive oil. If the temperature of the system is increased from 6.0 ºC to 31 ºC, how much oil spills from the flask?