1. HEAT
ConversionTemperatures:

2. Temperature Scales
Fahrenheit
Celsius
Kelvin

3. Helpful Hints Identify the equation needed.
Plug in the numbers to solve
Remember the math rules:
Solve what is in parenthesis first
Solve Multiplication & Division before addition and subtraction
Show all work
Put box around final answer

4. Solving 2–Step temperature equations
Necessary only when converting:
K to oF
oF to K

5. Temperature Conversion Equations
4 equations to use:
oF = 9/5oC + 32
oC = 5/9 (oF-32)
K = oC + 273
oC = K – 273

6. Convert 500 K to ____ o F First convert K to o C Then convert C to o F
Use this equation: oC = K – 273
Then convert C to o F
Use this equation: oF = 9/5oC + 32

7. Convert 500 K to ____ o F oC = K – 273 oC = 500 – 273 oC = 227
Step 1:
oC = K – 273
oC = 500 – 273
oC = 227
Step 2:
oF = 9/5oC + 32
oF = 9/5(227) + 32
oF = 1.8(227)+ 32
oF =
oF =

8. Convert 70 o F to ____ K
First convert o F to o C
Use this equation: oC = 5/9 (oF-32)
Then convert C to K
Use this equation: K = oC + 273

9. oC = 5/9 (oF-32) oC = 5/9 (o70-32) oC = 0.55 (38) oC = 2.11
Convert 70 o F to ____ K
Step 1:
oC = 5/9 (oF-32)
oC = 5/9 (o70-32)
oC = 0.55 (38)
oC = 2.11
Step 2:
K = oC + 273
K =
K =

10. Units of Heat Objectives are to:
define and distinguish between various units of heat
define the mechanical equivalent of heat
discuss everyday examples to illustrate these concepts
Temperature Conversions:

11. Units of Heat

12. Units of Heat
Heat is energy in transit, and is measured in energy units.
The SI unit is the joule (J), or Newton-metre (Nm).
Historically, heat was measured in terms of the ability to raise the temperature of water.
The kilocalorie (kcal), or Calorie (Cal), or “big calorie”: amount of heat needed to raise the temperature of 1 kilogramme of water by 1 C0 (from 14.50C to 15.50C)
The calorie, or “little calorie”: amount of heat needed to raise the temperature of 1 gramme of water by 1 C0 (from 14.50C to 15.50C)
In industry, the British thermal unit (Btu) is still used: amount of heat needed to raise the temperature of 1 lb of water by 1 F0 (from 630F to 640F)

13. Mechanical Equivalent of Heat
Joule demonstrated that water can be heated by doing (mechanical) work, and showed that for every 4186 J of work done, the temperature of water rose by 1C0 per kg.

14. Mechanical Equivalent of Heat
Conversion between different units of heat:
1 cal = 10-3 kcal = x 10-3 Btu = J
1 Cal = 1 kcal=4186 J

15. Sensible Heat Objectives are to:
describe what is meant by 'sensible heat‘
define specific heat
explain how the specific heat capacities of materials are obtained using calorimetry

16. Specific Heat Capacity
Sensible heat is associated with a temperature change (can be “sensed”)
Different substances have different molecular configurations and bonding  temperature change not generally the same for equal amounts of heat
Specific heat capacity, c: amount of energy needed to raise the temperature of 1 kg of a substance by 1K

17. Calorimeters

18. Calorimeters (contd.)

19. Calorimetry: An Exercise in Bookkeeping

20. Calorimetry: Finding Specific Heats

21. Calorimetry: Specific Heat

22. Calorimetry: Mixtures

23. Water: Specific Heat Capacities and Latent Heats

24. Water: Warming Curve

25. Water: Example Problem

26. Latent Heat Objectives are to: Describe what is meant by ‘latent heat‘
Compare and contrast the 3 phases of matter
Relate latent heat to phase changes

27. Phases of Matter Heat required for phase changes:
Vaporization: liquid  vapour
Melting: liquid  solid
Sublimation: solid  vapour
Heat released by phase changes:
Condensation: vapour  liquid
Fusion: liquid  solid
Deposition: vapour  solid

28. Phases of Matter

29. Latent Heat

30. Phase Diagrams

31. Phase Diagrams Visual representation of phase changes
Triple point: point at which all three phases coexist
Curves branching out from this point separate phase regions:
Fusion curve: solid-liquid boundary
Vaporization curve: liquid-gas boundary
Sublimation curve: solid-gas boundary

32. Phase Diagram: Water

33. Phase Diagram: Carbon Dioxide

34. Methods of Heat Transfer
Objectives are to:
describe the three methods of heat transfer
Give practical/environmental examples of each

35. Thermal Conduction

36. Convection

37. Radiation Heat transfer by electromagnetic waves
Does not need a material medium
Black body: perfect absorber  perfect emitter (at all wavelengths)

38. Radiation

39. Convection

40. Convection at Home

41. Convection

42. Greenhouse Effect

43. Greenhouse Effect

44. Heat Transfer

45. Radiation