1. THERMAL ENERGY

2. THERMAL EQUILIBRIUM Moves heat energy from warmer to cooler regions
Example, water/antifreeze in a radiator

3. HEAT VS. TEMPERATURE HEAT Measurement of heat energy
Form of energy found in the vibrating motion of atoms and molecules
TEMPERATURE
Measurement of heat energy
Scalar quantity
Fahrenheit (0F)
Celsius (0C)
Kelvin (K)

4. Heat increases the KE of the substance
The substance expands especially gases
Work may be done
Examples- rubber band, steeel balls

5. Total Energy is conserved
D PE + D KE + D U = 0

6. WHY DOES HEAT FLOW FROM HOT- TO- COLD?
Heat gives added energy to molecules which move faster and then the energy is passed on to surrounding cooler molecules

7. HOW DOES A THERMOMETER WORK?
When temperature in a mercury or colored alcohol glass tube increases, the liquid expands and rises up the tube

8. TEMPERATURE SCALES Scale Boiling Pt. Freezing Pt.
Fahrenheit F F
Celsius C C
Kelvin K K

9. CONVERSIONS 0C = 5/9 ( 0F - 320) 0F = 9/5 0C + 320 K = 0C + 273

10. SOLVE THIS PROBLEM
An electric motor is operating at a temperature of 1150F. It is located in a workshop where the room temperature is 750F.
Find the room temperature in 0C.
Find the room temperature in K.

11. ROOM TEMPERATURE IN 0C 0C = 5/9 ( 75-32) 0C = 5/9 ( 43 )

12. ROOM TEMPERATURE TO K
K = 0C + 273
K = = 297K

13. Conduction, Convection, Radiation
Conduction- The transfer of energy through matter in which energy moves from particle to particle ---touching; more easily in solids than liquids or gases
Convection-The transfer of energy by the bulk movement of matter in which particles move from place to place in a fluid---often movement of heat in air
Radiation- The transfer of energy in the form of waves—often from the SUN

14. Conductors & Insulators
Thermal conductors-substances that rapidly transfer heat energy
Insulators reduces heat loss by slow transfer of heat energy

15. Specific Heat Capacity
The quantity of heat required to raise the temperature of 1 kg of a substance by 10 C at constant pressure
The specific heat of water is J / g . 0C

16. Q = m c DT
Q = heat measured in J
c = specific heat capacity in J/kg. 0C
m = mass in kg
DT = temperature in 0C
Example- food lab

17. Phase Change
Melting or solidification
Latent heat – energy per unit mass that is transferred during a phase change of a substance
Can be heat of fusion or heat of vaporization

18. Heat of fusion- energy transferred to change from solid to liquid or liquid to solid
Heat of vaporization- energy transferred to change from liquid to vapor or vapor to liquid
Vaporizing or condensing

19. Phase Change graph

20. Laws of Thermodynamics
1st Law – The total change in internal energy from its initial to final equilibrium conditions is equal to the transfer of energy as both heat and work.

21. 2nd Law- No machine can transfer all of its absorbed energy as work
This can be explained as entropy- a measure of the disorder of a system, natural processes increase entropy
Increasing disorder means there is less energy to do work