1. Chapter 10 Thermal Physics 1. Temperature and the zeroth Law of Thermodynamics 2. Thermometers and Temperature Scales 3. Thermal Expansion

2. Thermal Physics What is Thermal Physics? What is Heat? What is Thermal Contact? What is Thermal Equilibrium?

3. Zeroth Law of Thermodynamics If objects A and B are separately in thermal equilibrium with a third object, C, then A and B are in thermal equilibrium with each other. Allows a definition of temperature

4. Thermometers What is a thermometer? A Mercury thermometer Gas thermometer

5. Temperature Scales How does one define a temperature Scale? The Celsius scale The Fahrenheit scale The Kelvin scale

6. Kelvin Scale Why do we need this scale? What is first point? What is triple point?

7. Some Kelvin Temperatures Some representative Kelvin temperatures Note, this scale is logarithmic Absolute zero has never been reached

8. Converting Among Temperature Scales

9. Converting Among Temperature Scales –Example 1. A pan of water is heated from 25 °C to 80 °C. What is the change in temperature on the Kelvin scale and on the Fahrenheit scale?

10. Thermal Expansion What is thermal expansion? Linear Expansion Area expansion Volume expansion

11. Applications of Thermal Expansion – Bimetallic Strip Thermostats Use a bimetallic strip Two metals expand differently Since they have different coefficients of expansion

12. Thermal Expansion – Example 1. A steel railroad track has a length of 30.00 m when the temperature is 0°C. What is its length on a hot day when the temperature is 40°C?

13. Thermal Expansion – Example 1. A hole of cross-sectional area 100.00 cm 2 is cut in a piece of steel at 20°C. What is the area of the hole if the steel is heated from 20°C to 100°C?

14. Unusual Behavior of Water