1. 10 Temperature Temperature & Scales Thermometry Thermal Expansion
Homework
13, 20, 24, 45, 50, 58, 59.

2. Temperature T ~ KE/molecule Ex: hammered metal?
Expansion with T increase 2 2

3. Superheating
Mythbusters
Instant coffee 3

4. Water Expansion
Water expands from 4°C to 100°C (as does most materials)
However, water contracts when warmed from 0°C to 4°C. (transient ice melting) 4 4

5. 5 5

6. Ideal Gas PV ~ T Ex: V constant: P ~ T Ex: P is constant: V ~ T.
Ex: T is constant: P ~ 1/V.

7. Constant Pressure
What % increase in V occurs for an ideal gas heated from 20C to 40C? (V ~ T)
(It does not double, b/c C is not a thermodynamic temperature scale)
V2/V1 = T2/T1 = (273+40)/(273+20) = 1.068
6.8% increase in volume.

8. Linear Thermal Expansion
DL = a Lo DT
Example: 100C increase in Aluminum causes a fractional increase in length of = 0.24% change.

9. Bi-Metallic Strips

10. Summary T is KE/molecule measured in C, K, F. Gas Laws
Thermal Expansion