1. Thermodynamics Day 1

2. Section 1 Notes: Temperature Scales and Conversions  Intro Question 1. How does a thermometer determine temperature?

4. Thermodynamics (Unit 1 spring)

5. Thermodynamics- Physics that deals with heat and its conversion into other forms of energy.

6. Video Clip: The Thermometer 1:36

7. Video Clip: Fahrenheit and Celsius Scales 5:14

9. Temperature Variables T K = Temperature Kelvin T C = Temperature Celsius T F = Temperature Fahrenheit

10. Video: Absolute Zero 1:49

11. Absolute Zero= 0 Kelvin, a temperature where no motion would occur. There is no kinetic energy in the molecules. 0 Kelvin= -273.15 ºCelsius

12. Conversion Scale ( )

13. Example 1 A healthy person has an oral temperature of 98.6 ºF. What would this reading be on the Celsius scale?

14. Example 1 A healthy person has an oral temperature of 98.6 ºF. What would this reading be on the Celsius scale?

15. Example 2 A time and temperature sign on a bank indicates the outdoor temperature is -20.0 ºC. What is the corresponding temperature on the Fahrenheit scale?

16. Example 2 A time and temperature sign on a blank indicates the outdoor temperature is -20.0 ºC. What is the corresponding temperature on the Fahrenheit scale?

17. The Kelvin Temperature Scale Has scientific significance due to its absolute zero point. Has equal divisions as the Celsius scale Not written in degrees 0 º C is 273.15 K Therefore the conversion is:

18. CP: –Finish Worksheet Problems 1-4 Honors: –Finish Worksheet Problems 1-4

19. Day 2

20. Intro 1. Convert 50º F into ºC and Kelvin

21. Intro 1. Convert 50º F into ºC and Kelvin

22. Intro 1. Convert 50º F into ºC and Kelvin

23. Video: Voyage up the Celsius Scale 11:09

24. Section 2 Notes: Kinetic Energy and Temperature Kinetic energy (KE)- Energy of movement Temperature- A measure proportional to the average kinetic energy of a substance. –higher temperature = higher kinetic energy –The more kinetic energy the quicker the molecules are moving around

25. Click on the diagram to be taken to the page

26. Draw a picture representing molecular motion of three identical molecules at these two temperatures

28. Section 3 Notes: Internal Energy vs. Heat Internal energy (U)- Sum of the molecular energy –kinetic energy, potential energy, and all other energies in the molecules of a substance. –Unit: Joule Heat (Q) is energy in transit –energy flows from a hot to a cold substance. –Unit: Joule An object never has “heat” or “work” only internal energy (heat is transferred and work is done)

29. Heat is energy in transit Heat lost by one object equals heat gained by another Heat lost = Heat gained -Q A = Q B

30. Heat transfers from hot to cold (a)Holding a hot cup (b)Holding a cold glass (heat leaving your hand feels cold)

31. The coffee looses 468J of heat. How much heat does Bob gain? (assuming no heat was lost to the surroundings) The same: Bob gained 468 J of heat Example 3

32. –Direction: From high temperature to low temperature –Rate of transfer depends on temperature difference: The greater temperature difference the greater the energy transfer T water = 20º C T can = 15º C T water = 35º C T can = 5º C

34. Example 4 Where would the greater energy transfer take place and which way would the energy transfer? A.Ice = 0 ºC Juice = 20 ºC B.Ice = 0 ºC Juice = 25 ºC B. has a bigger temperature difference and therefore greater energy transfer. Energy transfers from hot to cold: Juice to Ice

35. What happens when the temperature inside and out are equal? T water = 11º C T can = 11º C

36. Heat is transferred until there is thermal equilibrium Thermal Equilibrium- When temperatures are equal and there is an even exchange of heat T water = 11º C T can = 11º C

37. Section 4 Notes: Heat Transfer Types of Heat Transfer: –Conduction –Convection –Radiation

38. Conduction- Caused by vibrating molecules transferring their energy to nearby molecules. Not an actual flow of molecules. heat transfer

39. Thermal conductors- rapidly transfer energy as heat Thermal insulators- slowly transfer energy as heat

40. Challenge Put the following in order of most thermally conductive to least. Copper, Wood, Air, Water, Concrete 1 2 3 4 5

41. 1. Copper 2 Concrete 3. Water 4. Wood 5. Air

42. Convection- process in which heat is carried from place to place by the bulk movement of a fluid (gas or liquid). Examples

43. Radiation (electromagnetic radiation) – Reduce internal energy by giving off electromagnetic radiation of particular wavelengths or heated by an absorption of wavelengths. Ex. The UV radiation from the sun making something hot. Absorption depends on the material.

44. Draw your own pictures in the table that represent these three types of heat transfer.

46. CW Finish questions 5 and 6 on the worksheet

47. Day 3

48. Intro Intro question/activity: –Draw these two tables in your intro section. In (a) represent the motion of three identical molecules at these two temperatures. In (b) draw a picture representing these three types of heat transfer. Try not to look at your notes until you are done. (a) (b)

49. Intro Draw a picture representing molecular motion of three identical molecules at these two temperatures

50. Intro Draw your own pictures in the table that represent these three types of heat transfer.

51. Section 5: Laws of Thermodynamics

52. A System System- A collection of objects upon which attention is being focused on. This system includes the flask, water and steam, balloon, and flame. Surroundings- everything else in the environment The system and surrounding are separated by walls of some kind. System Surroundings

53. Walls between a system and the outside Adiabatic walls- perfectly insulating walls. No heat flow between system and surroundings.

54. In a system: How can you measure the quantity of heat entering or leaving? Q = Δ UorQ = U f – U 0 Q: The quantity of heat that enters or leaves a system U 0 : Initial internal energy in system U f : Final internal energy in system If Q is positive then energy entered the system If Q is negative then energy left the system This is directly related to temperature. –If the system gets colder then heat left –If the system gets warmer then heat entered

55. Example 5 The internal energy of the substance is 50 J before The internal energy of the substance is 145 J after a) How much heat was transferred in this system? b) Did it enter or leave?

56. First Law of Thermodynamics: –Conservation of energy applied to thermal systems. –Energy can neither be created nor destroyed. It can only change forms –Stated in an equation ΔU = Q + W

57. First Law of Thermodynamics: Conservation of Energy ΔU = Q + W –Internal Energy (U) (positive if internal energy is gained) –Heat (Q) (positive if heat is transferred in) –Work (W) (positive if work is done on the system) –The unit for all of these is the Joule (J)

58. Example 6 & 7 6. A system gains 1500 J of heat from its surroundings, and 2200 J of work is done by the system on the surroundings. What is the change in internal energy? 7. A system gains 1500 of heat, but 2200 J of work is done on the system by the surroundings. What is the change in internal energy?

59. 6. A system gains 1500 J of heat from its surroundings, and 2200 J of work is done by the system on the surroundings. What is the change in internal energy? 7. A system gains 1500 of heat, but 2200 J of work is done on the system by the surroundings. What is the change in internal energy? 1500 - 2200 1500 + 2200 Example 6 & 7

60. Now how can you tell if work is done by or on a system? Is work done on or by the system ? a)nail/wood system b) Bunsen burner, flask, balloon system

61. Work is done by the man causing frictional forces between the nail and the wood fiber. Work increases the internal energy of the wood and nail. Work done on a system: Work to Internal Energy

62. Work done by a system: Internal Energy to Work The balloon expands doing work on its surroundings The expanding balloon pushes the air away

63. Work done on or by a gas Volume must change or no work is done. On a gas- Volume decreases (work must be done to force molecules into a smaller area) By a gas- Volume increases (the pressure of the gas causes the volume to increase)

64. Section 5 Notes 4 Common Thermal Processes Isobaric Process Isochoric process (isovolumetric) Isothermal process Adiabatic process Each will have their own assumptions

65. 4 Thermal Processes Isobaric Process – occurs at constant pressure ΔP = 0

66. 4 Thermal Processes Isochoric process (Isovolumetric) – one that occurs at constant volume. ΔV = 0 and therefore W = 0

67. Thermal Processes Isothermal process – one that occurs at constant temperature T (temperature) directly relates to U (internal energy) ΔU = 0

68. Thermal Processes Adiabatic process – on that occurs with no transfer of heat ΔQ = 0

69. Look for these terms in questions since they assume givens Isobaric Process ΔP = 0 Isochoric process ΔW = 0 Isothermal process ΔU = 0 Adiabatic process ΔQ = 0

70. Example 8 How much heat has entered or left the system when 500J of work has been done on the system in an isothermal process?

71. Example 8 How much heat has entered or left the system when 500J of work has been done on the system in an isothermal process?

72. Example 9 How much work is done on or by the system when internal energy increases by 55J in n adiabatic process?

73. Example 9 How much work is done on or by the system when internal energy increases by 55J in n adiabatic process?

74. CW/HW Do the first law of thermodynamics questions 7-10 on the worksheet Define the 16 words on the worksheet

75. Day 4

76. Intro 1.What does an adiabatic process tell you? 2.What does an isovolumetric process tell you? 3.What does an isothermal process tell you 4.How much work is done on or by the system when internal energy decreases by 45J in an adiabatic process? 5.What is the change in internal energy if 650 J of work is done and 50J of heat is transferred in?

77. Section 6: Three Laws of Thermodynamics

78. First Law of Thermodynamics 1.Energy can neither be created nor destroyed Energy Conservation: Conservation of energy applied to thermal systems.. It can only change forms When heat is added to a system, it transforms to an equal amount of some other form of energy. Equation: ΔU = Q + W (work is done on a system)

79. Second Law of Thermodynamics 2.Entropy in a system increases over time. Entropy- Measure of randomness or disorder in a system This occurs even when a system is left untouched. Other parts of the second law of thermodynamic Heat goes from hot to cold. No cyclic process is 100% efficient it can’t convert heat entirely into work Some energy will always be transferred out to surroundings as heat.

80. Third Law of Thermodynamics 3. absolute zero cannot be reached As a system approaches absolute zero, all processes cease and the entropy of the system approaches a minimum value. A theoretical impossibility –If it occurred everything would stop and there would be no more entropy

81. Section 7: Transformation of energy in a heat engine

82. The Heat Engine –a device that used a difference in temperature of two substances to do mechanical work –It transferring energy from a high-temperature substance (the boiler) to a lower temperature substance –For each complete cycle: W net = Q h - Q c What the variables stand for here: Q h = Heat from high temperature substance Q c = Heat to low temperature substance W or work equals the difference of Q h and Q c

83. The Heat Engine How it works: main points There will be an area of high temperature (boiler) and an area of low temperature Heat wants to go from a high temperature to a low temperature. Work is done by capturing energy in the transfer and using it to do work The work done by the engine equals the difference in heat transferred from the hot to cold substance.

84. The Heat Engine –For each complete cycle: Work = Energy transferred as heat from the high temperature substance to the colder temperature substance What the variables stand for here: Q h = Heat from high temperature substance Q c = Heat to low temperature substance W or work equals the difference of Q h and Q c

85. Example 10 A heat engine is working at 50% efficiency. How much work is done between a 670J and 200J reservoir?

86. Example 10 A heat engine is working at 50% efficiency. How much work is done between a 670J and 200J reservoir?

87. Example 11: Example 11: (just added and not on your worksheet) Do this question on free space below example 10 A heat engine has a 5000 J reservoir and a 2000J reservoir. If the engine can does 2100J of work, how efficient is it?

92. Nuclear Physics

93. Intro: 1.What atom is this? 2.Where do you find protons? 3.Where do you find neurons? 4.Where do you find electrons? 5.How many protons does it have? 6.How many neutrons? 7.Is it a neutral atom, and how do you know?

94. The Atom In the nucleus (nucleons) Proton- (+) charged particle Neutron- no charge Outside the nucleus Electron- (-) charged particle has almost no mass

95. Nucleons Are particles occupying the nucleus Consist of + charged protons and neutral neutrons Have almost 2000 times the mass of electrons

96. Where can you find the number of protons? It’s the atomic number (found on the periodic table)

97. Nuclear Notation Atomic number = no. of protons Atomic mass = protons + neutrons Atomic number is the same as the number of electrons in an uncharged atom 5 B 10.811 Atomic Number Atomic Mass

98. 1a. How many protons? 1b. How many neutrons? 1c. How many nucleons? You may see atomic number written many ways. The smaller number is the atomic number and the larger is the atomic mass Question 1

99. has 13 protons and 14 neutrons for a total of 27 nucleons has 13 protons and 15 neutrons for a total of 28 nucleons The identity of an element depends on the number of protons 28 13

100. Isotopes: Atoms of the same element with different numbers of neutrons (different masses) Most common stable isotope of carbon Unstable radioactive isotope of carbon

101. Question 2 List the four fundamental forces from strongest to weakest 1. 2. 3. 4.

102. Review of Fundamental forces Strongest to weakest 1.Strong Nuclear Force 2.Electromagnetic Force 3.Weak Nuclear Force 4.Gravity

103. Forces Acting on Nucleons: Forces of attraction between nucleons Strong forces –Are independent of the charge of the nucleon –Are short range (exist only between closest neighbors) Electrical force (electrostatic) –Force of repulsions between positively charged protons –Are long range

104. When are nuclei unstable? (naturally radioactive) a.Large nuclei (Z > 82) – electrical forces of repulsion are greater than strong forces of attraction b.Wrong neutron : proton ratio stable nucleusno. of protonsno. of neutrons 66 1314 2630 5681 82125

105. When are nuclei unstable? Bigger atoms require more neutrons per proton to keep the atom stable

106. A radioactive isotope: Has an unstable nucleus Spontaneously emits a particle and decays into another element (to become more stable)

107. Transmutation Changing into another element through radioactive decay

108. Who am I?

109. I worked with my husband and discovered radium, a radioactive material

110. Marie and Pierre Curie First to discover that compounds containing uranium emitted penetrating rays. Discovered radioactive polonium and radium

111. Types of Radioactive Emission SymbolCompositionStopped By Alpha2p + 2n (helium) Paper Beta1e (electron) Aluminum GammaγEnergy only Lead

112. Use a periodic table for decay equations

113. Alpha Decay Radiation through the loss of 2p + 2n or (helium)

114. Beta Decay Radiation where a neutron splits, giving off an electron and becoming a proton in the new element

115. Gamma Decay A change energy state gives off a gamma particle or photon

116. Question 3a Balance the nuclear equation after alpha decay

117. Question 3a Balance the nuclear equation after alpha decay

118. Question 3b Balance the nuclear equation after beta decay Remember in beta decay a neutron changes into a proton by giving off an electron

119. Question 3b Balance the nuclear equation after beta decay Remember in beta decay a neutron changes into a proton by giving off an electron

120. Extra Question Which radioactive isotope completes this nuclear decay equation 6

121. Extra Problem Finish off the equation

122. Half Life and Half Life Calculations Half Life- time it takes for half of the radioactive sample to decay. –Ranges from a fraction of a second to billions of years Decay constant- Probability per time that a nucleus would decay

123. CW/HW Do Page 1 of the worksheet: Nuclear and Thermodynamics Extra Practice

124. Section 2 Intro 1.Rewrite and balance the equation above 2.What kind of decay is shown above? 3.What is the particle given off during alpha decay composed of? 4.What is the particle given off during beta decay composed of?

125. Section 2: Nuclear Physics Math

126. Half Life Calculations # of Half LivesFraction Remaining Fraction Decayed How much of 100g sample left How much of 100g sample decayed 01.00100g0 1 2 3 4 5

127. Half Life and Half Life Calculations y= fraction of radioactive material left n= number of half lives T 1/2 = half life time

128. Example A How much of the original radioactive material is left after 15 half-lives?

129. Example A How much of the original radioactive material is left after 15 half-lives?

130. Not every radioactive isotope is created equal ParentDecays into:Half life (years) Carbon-14Nitrogen-145,730 Aluminum-26Magnesium-26740,000 Iodine-129Xenon-12917 million Uranium-235Lead-207704 million Potassium-40Argon-401.3 billion Rubidium-87Strontium-8749 billion

131. Example B We start with 400g of a sample, how many grams would remain after 3 half lives? #1 figure out the fraction remaining (y) #2 multiply the fraction remaining by the mass of the original sample (y) x (m o ) m o = initial mass of radioactive material

132. Example B

133. Example C A radioactive sample has a mass of 56 mg and a half life of 30 minutes. How much of the sample remains after 60 minutes have passed? Step#1 find number of half lives (n) Step#2 find what fraction remains (y) Step#3 if an initial sample was given multiply fraction remaining (y) x (the initial sample mass)

134. Example C A radioactive sample has a mass of 56 mg and a half life of 30 minutes. How much of the sample remains after 60 minutes have passed? Step#1 find number of half lives (n) Rearranges to

135. Example C A radioactive sample has a mass of 56 mg and a half life of 30 minutes. How much of the sample remains after 60 minutes have passed? Step#1 find number of half lives (n) = 2 Step#2 find what fraction remains (y)

136. Example C A radioactive sample has a mass of 56 mg and a half life of 30 minutes. How much of the sample remains after 60 minutes have passed? Step#1 find number of half lives (n) = 2 Step#2 find what fraction remains (y) = 0.25 Step#3 if an initial sample was given multiply fraction remaining (y) x (the initial sample mass) 56 x 0.25 = 14 grams

137. Example D An unknown radioactive material has a half life of 4000 years. How much of the sample will remain after 20,000 years? Rearranges to

138. Example D An unknown radioactive material has a half life of 4000 years. How much of the sample will remain after 20,000 years? Rearranges to

139. Example E

140. Example E (n) Number of half lives original 12345 Quantity remaining 32g16g8g4g2g1g

141. Example E (n) Number of half lives original 12345 Quantity remaining 32g16g8g4g2g1g

142. Example E (n) Number of half lives original 12345 Quantity remaining 32g16g8g4g2g1g

143. Useful applications of radioactivity Can be detected and therefore small amounts can be used as tracers for medical diagnosis Larger amounts can be used as treatments for certain types of cancers (cancer cells are killed before healthy cells) Can be used to determine the age of rocks and fossils

144. Show what you know

149. Types of Nuclear Reactions Natural transmutation – Uranium spontaneously decays Artificial transmutation – bombardment of a stable isotope to force it to decay

150. Question 4 Balance the reaction after the following artificial transmutation.

151. Types of Nuclear Reactions Artificial transmutation First done by Earnest Rutherford When the bullets are positively charged, they are repelled by the nucleus they are bombarding. To overcome the repulsions, they must be accelerated to very high speeds by particle accelerators.

152. Nuclear Fission Nuclear fission - Heavy nuclei are bombarded with neutrons and split. plus a tremendous amount of energy

153. Nuclear fission Mass of particles produced is slightly less than the mass of the reactants. This mass is converted into energy. (E=mc 2 )

154. Nuclear fission is a chain reaction. Neutrons are needed to start and released as a product which can start more reactions. Critical mass: minimum mass of fissionable material required for a chain reaction.

155. Problems with Fission Nuclear fission produces radioactive waste that has a large half life. U-235 Uranium 235 –Half life of U-235 is 713 million years We cannot get rid of this dangerous product so we store it away from anything it can harm. –We deeply bury Meltdown if cooling system fails the reactor can overheat and melt releasing radioactive materials

156. Nuclear fusion – combination of small nuclei into larger with release of energy. Mass of particles produced is much less than the mass of the reactants. This mass is converted into energy. (E=mc 2 ) Can release up to 10 times that of fission Occurs naturally in our sun and other stars Does not give off radioactive waste

157. Problems with Fusion Fusion requires high temperatures like those in the stars. We cannot sustain these temperatures without vaporizing the container of the fusion reaction. Today many are looking into ways of making fusion work under sustainable conditions