Mastery Learning - First Law of Thermodynamics & Energy Balance Website: Applied Sciences Education Research Group (ASERG) Faculty of Applied Sciences Universiti Teknologi MARA Voice:

Quotes "One who learns by finding out has sevenfold the skill of the one who learned by being told.“ - Arthur Gutterman "The roots of education are bitter, but the fruit is sweet." -Aristotle

AdvantagesDisadvantages (easily dealt with) Preparation Teachers must state objectives before designating activities Requires teachers to do task analysis, thereby becoming better prepared to teach the unit. Students progress at different pace; so students who have mastered must wait for those who haven’t or must individualize instruction. Must have a variety of materials for re- teaching. Teacher must state objectives clearly. Teacher must perform task analysis. Instructional Strategy - Mastery Learning

AdvantagesDisadvantagesPreparation Requires teachers to state objectives before designating activities Can break cycle of failure (especially important for minority and disadvantaged students) Must have several tests for each unit If only objective tests are used, can lead to memorizing and learning specifics rather than higher levels of learning Teacher must be alert and patient in dealing with the pace of the pupils. Instructional Strategy - Mastery Learning

First Law of Thermodynamics & Energy Balance – Control Mass, Open System Website: Applied Sciences Education Research Group (ASERG) Faculty of Applied Sciences Universiti Teknologi MARA Voice:

CHAPTER 4 The First Law of Thermodynamics

Introduction 1.Identify the energies causing a system’s properties to change. 2.Identify the energy changes within the system. 3.State the conservation of energy principle. 4.Write an energy balance for a general system undergoing any process. Objectives:

Introduction 5.Write the unit-mass basis and unit-time basis (or rate-form basis) energy balance for a general system undergoing any process. 6.Write the energy balance in terms of all the energies causing the change and all the energy changes within the system. 7.Write a unit-mass basis and unit-time basis (or rate-form basis) energy balance in terms of all the energies causing the change and all the energy changes within the system. Objectives:

Introduction 8.State the conditions for stationary, closed system and rewrite the energy balance and the unit-mass basis energy balance for stationary- closed systems. 9.Apply the energy conservation principle for a stationary, closed system undergoing an adiabatic process and discuss its physical interpretation. Objectives:

Introduction 10.Apply the energy conservation principle for a stationary, closed system undergoing an isochoric, isothermal, cyclic and isobaric process and discuss its physical interpretation. 11.Give the meaning for specific heat and state its significance in determining internal energy and enthalpy change for ideal gases, liquids and solids. 12.Use the energy balance for problem solving. Objectives:

Instructional Plan-Mastery Unit 1: Objectives: 1.Identify the energies causing the system to change. 2.Identify the energy changes within the system. 3.State the conservation of energy principle. 4.Write an energy balance for a general system undergoing any process.

Instructional Plan-Mastery Unit 2: Objectives: 5.Write the unit-mass basis and unit-time basis (or rate-form basis) energy balance for a general system undergoing any process. 6.Write the energy balance in terms of all the energies causing the change and the energy changes within the system. 7.Write a unit-mass basis and unit-time basis (or rate-form basis) energy balance in terms of all the energies causing the change and the energy changes within the system.

Instructional Plan-Diagnose Preparatory Diagnostics If P = 100 kPa, T = 25  C, determine the phase of water, its specific volume, its specific enthalpy and its specific internal energy. How can you boil the water? What types of energy can you give to boil it? What is the boiling or saturation temperature? What is the phase, the specific volume and the specific internal energy when the temperature reaches 150  C, at constant pressure?

Instructional Plan - Re-teach Preparatory Diagnostics Students’ activity: Students’ activity: read the saturated-water, pressure property table. Obtain and u. Students’ activity: Students’ activity: Check table for the saturation temp at 100 kPa. Then suggests 2 ways of boiling water. Students’ activity: Students’ activity: Suggest the phase and provide reason. Then suggest method on how to find and u. Failure to complete task: re-teach then give different example Otherwise, proceed with the lesson’s learning outcome

3-1 Instructional Plan - Re-teach Lem Oven 200  C Nasi Lemak 20  C Nasi Lemak 20  C q in H 2 O: Sat. Liq. Sat. Vapor P = 100 kPa T = 99.6  C P = 100 kPa T = 99.6  C Q in What happens to the properties of the system after the energy transfer? SODA 5  C SODA 5  C SODA 5  C SODA 5  C q in q out 25  C Teacher Activity Energy transfer-Thermal (heat)

Example: A steam power cycle. Steam Turbine Mechanical Energy to Generator Heat Exchanger Cooling Water Pump Fuel Air Combustion Products System Boundary for Thermodynamic Analysis System Boundary for Thermodynamic Analysis Q out W in W out Q in The net work output is Desiredoutput Requiredinput Teacher Activity Instructional Plan - Re-teach

Energy Transfer – Work Done i i Voltage, V No heat transfer T increases after some time No heat transfer T increases after some time H 2 O: Super Vapor H 2 O: Super Vapor Mechanical work: Piston moves up Boundary work is done by system Mechanical work: Piston moves up Boundary work is done by system Electrical work is done on system H 2 O: Sat. liquid W pw,in,kJ W e,in = Vi  t/1000, kJ Teacher Activity

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 4-8 FIGURE 4-46 Pipe or duct flow may involve more than one form of work at the same time. Teacher Activity

First Law – Energy Transfer System in thermal equilibrium System Total energy E 1 Can it change? How? Why? System’s initial total energy is E 1 = E 1 = U 1 +KE 1 +PE 1 U 1 +KE 1 +PE 1 or e 1 = u 1 +ke 1 +pe 1, kJ/kg Teacher Activity

First Law – Energy Transfer A change has taken place. System, E 1 System E 1 = U 1 +KE 1 +PE 1 Movable boundary position gone up System expands Teacher Activity

First Law – Energy Transfer A change has taken place System, E 1 System Initial Final System’s final energy is E 2 =U 2 +KE 2 +PE 2 E 1 = U 1 +KE 1 +PE 1 Movable boundary position gone up System expands Teacher Activity

First Law – Energy Transfer How to relate changes to the cause Heat as a cause (agent) of change System E 1, P 1, T 1, V 1 To q in, or Q in q out, or, Q out Properties will change indicating change of state E 2, P 2, T 2, V 2 Teacher Activity

First Law – Energy Transfer Work as a cause (agent) of change System E 1, P 1, T 1, V 1 To Properties will change indicating change of state W in,  in, kJ/kg W out,  in, kJ/kg How to relate changes to the cause E 2, P 2, T 2, V 2 Teacher Activity

First Law – Energy Transfer How to relate changes to the cause Mass transfer as a cause (agent) of change System E 1, P 1, T 1, V 1 To Properties will change indicating change of state Mass out Mass in E 2, P 2, T 2, V 2 Teacher Activity

First Law – Energy Transfer How to relate changes to the cause Dynamic Energies as causes (agents) of change System E 1, P 1, T 1, V 1 To Properties will change indicating change of state Mass out Mass in W in W out Q in Q out E 2, P 2, T 2, V 2 Teacher Activity

First Law-Conservation of Energy Principle Energy must be conserved in any process. Energy cannot be created nor destroyed. It can only change forms. Total Energy before a process must equal total energy after process Known as Conservation of Energy Principle In any process, every bit of energy should be accounte d for!! z =h z =0 z =h/2 E=U+KE+PE = U+0+PE Teacher Activity

First Law-Conservation of Energy Principle Energy must be conserved in any process. Energy cannot be created nor destroyed. It can only change forms. Total Energy before a process must equal total energy after process Known as Conservation of Energy Principle In any process, every bit of energy should be accounte d for!! z =h z =0 z =h/2E=U+KE+PE E=U+KE+PE=U+0+PE Teacher Activity

First Law-Conservation of Energy Principle Energy must be conserved in any process. Energy cannot be created nor destroyed. It can only change forms. Total Energy before a process must equal total energy after process Known as Conservation of Energy Principle In any process, every bit of energy should be accounte d for!! z =h z =0 z =h/2E=U+KE+PE E=U+KE+0 Teacher Activity

First Law Energy Balance Energy Balance Amount of energy causing change change must be equal to amount of energy change change of system Energy Entering a system - Energy Leaving a system = Change of system’s energy Teacher Activity

First Law of Thermodynamics Energy Balance E in – E out =  E sys, kJ or e in – e out =  e sys, kJ/kg or Energy Entering a system - Energy Leaving a system = Change of system’s energy Teacher Activity

First Law of Thermodynamics How to relate changes to the cause Dynamic Energies as causes (agents) of change System E 1, P 1, T 1, V 1 To E 2, P 2, T 2, V 2 Properties will change indicating change of state Mass out Mass in W in W out Q in Q out Teacher Activity

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 4-1 FIGURE 4–7 The energy change of a system during a process is equal to the net work and heat transfer between the system and its surroundings. Teacher Activity

Instructional Plan-Activity Active Cooperative (group) Learning Name the energies which are agents of change Name the energies within a system. Draw and label energy interacting with a system and the energy changes within a system Student Activity Draw the energies interacting with an open system State the general energy conservation principle Quantitatively solve some numerical problems

Instructional Plan - Assess Active Cooperative (group) Learning Failure to complete task: re-teach then give different example Otherwise, proceed with the next unit Teacher-students Activity If all ok, increase difficulty level to application, analysis, synthesis and evaluation

Instructional Plan-Mastery Unit 2: Objectives: 5.Write the unit-mass basis and unit-time basis (or rate-form basis) energy balance for a general system undergoing any process. 6.Write the energy balance in terms of all the energies causing the change and the energy changes within the system. 7.Write a unit-mass basis and unit-time basis (or rate-form basis) energy balance in terms of all the energies causing the change and the energy changes within the system.

First Law – Interaction Energies Energy Balance – The Agent E in = Q in +W in +E mass,in,kJ e in = q in +  in +  in, kJ/kg Teacher Activity

First Law - Interaction Energies Energy Balance – The Agent E out = Q out +W out +E mass,out,kJ e out = q out +  out +  out, kJ/kg Teacher Activity

First Law - System’s Energy Energy Balance – The Change WIthin Energy change within the system,  E sys = E 2 -E 1 Internal energy change,  U = U 2 – U 1 kinetic energy change,  KE = KE 2 – KE 1 potential energy change,  PE = PE 2 – PE 1 is the sum of Teacher Activity

First Law – Energy Change Energy Balance – The Change WIthin  E sys =  U+  KE+  PE, kJ  e sys =  u+  ke+  pe, kJ/kg Teacher Activity

First Law – General Energy Balance Energy Balance E in – E out =  E sys, kJ or e in – e out =  e sys, kJ/kg or Energy Entering a system - Energy Leaving a system = Change of system’s energy Teacher Activity

First Law – General Energy Balance Energy Balance – General system Q in + W in + E mass,in – Q out – W out - E mass,out q in +  in +  in – q out –  out –  out =  U+  KE  +  PE, kJ =  u+  ke  +  pe, kJ/kg Teacher Activity

Instructional Plan-Activity Active Cooperative (group) Learning Student Activity Write an energy balance representing the net interacting energies (agents of change) and the energy changes in the system Write an energy balance in unit mass form, representing the net interacting energies (agents of change) and the energy changes in the system Write an energy balance in unit time form or rate form, representing the net interacting energies (agents of change) and the energy changes in the system

Instructional Plan - Assess Active Cooperative (group) Learning Failure to complete task: re-teach then give different example Otherwise, proceed with the next unit Teacher-students Activity If all ok, increase difficulty level to application, analysis, synthesis and evaluation