1. Ch 16 Thermal Energy and Heat 16.1 Thermal Energy and Matter
Work and Heat
Heat is transfer of E from one object to another
Moves from hot to cold objects
Temp
Avg KE of object
0K is absolute zero
Thermal E
Need mass, temp, and state of matter
Total KE and PE of the motion of particles in the object

2. Thermal Contraction/Expansion
Expansion: increase in volume due to temp increase
Contraction: decrease in volume due to temp decrease
Specific Heat
Q= m x c x ΔT
Heat = mass x specific heat x change in temp
Calorimeter
Measures heat flow

3. 16.2 Heat and Thermodynamics
Conduction
Trans thermal E by touching between objects
Faster in liquids/solids bc more particles touching
Thermal conductors: material that transfer well
Thermal insulator: material conducts poorly
Convection
Convection currents: warm rises and cold falls
Air or water cycling
Radiation
Trans of heat by waves through space
Think sun’s radiation!

4. First Law Thermodynamics
Energy is conserved
E cannot be created or destroyed, changes form
Second Law Thermodynamics
If thermal E flows from hotter to colder object
Thermal E can only flow from colder object to hotter object if work is done to system
Third Law Thermodynamics
Absolute 0 (0K) cannot be reached
No machine is 100% efficient so can only cool close to absolute zero

5. 16.3 Using Heat Heat Engines External Combustion Internal Combustion
Steam engine
Burns fuel outside engine
Internal Combustion
Car engines
Burns fuel inside engine
Combustion engine with pistons that move up/down (strokes)

6. Heating Systems Central heating systems Hot-water heating
Heats many rooms from one central location using vents
Hot-water heating
Boiler heats water and pumps it to where needed, cold water returned back
Steam heating
Steam is used instead of hot water
Electric Baseboard Heating
Electrical energy to heat room (like stove concept) heated coil warms air
Forced-Air Heating
Goal to maintain even room temp
Heat vents on floor houses with real winters

7. Cooling Systems Heat pump reverses flow of thermal E
Refrigerant fluid that vaporizes/condenses within tubes of heat pump
Refrigerators
Transfer of colder to warmer objects using heat pump