1. Heat and Temperature presented by Dr. Geller 10 September 2015
HNRT 227 Fall 2015 Chapter 4
Heat and Temperature
presented by Dr. Geller
10 September 2015

2. Do You Remember These?
Units of length, mass and time, and metric Prefixes
Density and its units
The Scientific Method
Speed, velocity, acceleration
Force
Falling objects
Newton’s Laws of Motion
Newton’s Law of Universal Gravity
Work
Potential Energy and Kinetic Energy
Conversion of Energy
Types/Sources of Energy

3. Main Concepts for Chapter 4
Kinetic Molecular Theory
Temperature
Heat
Phases of matter
Thermodynamics

4. 1st Law of Thermodynamics
In an isolated system, the total amount of energy, including heat energy, is conserved.
ENERGY IS CONSERVED

5. Temperature
A relative term reflecting how vigorously atoms in a substance are moving and colliding
Alternative definition
the average kinetic energy of the molecules in a region

6. Temperature Units Where is absolute zero?
Fahrenheit
Celsius
Kelvin
Where is absolute zero?
At what temperature does water freeze? Boil?

8. Heat Heat is a form of energy Units of heat
the energy flows from a warmer object to a cooler object
Units of heat
calorie
amount of temperature needed to raise temperature of 1 gram of water 1 degree Celsius
kilocalorie (kcal or Calorie)
amount of temperature needed to raise temperature of 1 kg of water 1 degree Celsius

9. Specific Heat Ability of a material to absorb heat energy
proportional to mass
proportional to change in temperature
Q = m*c*DT (note: not in textbook)
c is the SPECIFIC HEAT of the substance
amount of energy needed to increase temperature of 1 gram of substance 1 degree Celsius

10. Transfer of Heat Conduction Convection
“movement of heat by collisions between vibrating atoms or molecules”
Convection
“transfer of heat by the physical motion of masses”
cooler liquids or gasses descend while warmer liquids or gasses rise

11. Phases and Phase Diagram (NOT IN TEXT but IMPORTANT)

12. 2nd Law of Thermodynamics
Two key components
heat flows from a warmer body to a cooler body
entropy increases remains constant or increases in time