Work, Energy, Power and Machines

Power and its Applications

By the end of the lesson, the learner should be able to:
Define power as rate of doing work
-Calculate power using P = W/t and P = Fv
-State SI unit of power (Watt)
-Understand power ratings of appliances
-Solve problems involving power calculations

In groups, learners are guided to:
Q/A on energy conservation
-Definition of power with examples
-Derivation of P = W/t and P = Fv
-Discussion on power ratings of electrical appliances
-Worked examples on power calculations
-Investigation: measuring power of students climbing stairs

Stopwatch
-Measuring tape
-Spring balance
-Calculator
-Electrical appliances for power ratings
-Stairs for practical work
-Power calculation charts

KLB Secondary Physics Form 3, Pages 106-108

Work, Energy, Power and Machines

Simple Machines - Introduction and Terminology
Levers - Types and Applications
Pulleys - Fixed and Movable

By the end of the lesson, the learner should be able to:
Define machines and their purposes
-Understand load, effort, and fulcrum
-Define mechanical advantage, velocity ratio, and efficiency
-Calculate M.A., V.R., and efficiency
-Understand relationship between these quantities
Classify levers into three types
-Identify examples of each type of lever
-Apply principle of moments to levers
-Calculate forces in lever systems
-Understand applications of different lever types

In groups, learners are guided to:
Review power concepts through Q/A
-Introduction to machines and their uses
-Demonstration: simple lever showing load, effort, fulcrum
-Definition and calculation of M.A., V.R., and efficiency
-Worked examples on machine calculations
-Discussion on why efficiency is always less than 100%
Q/A on machine terminology
-Classification of levers: Class I, II, and III
-Demonstration: examples of each lever type
-Application of principle of moments
-Worked examples on lever calculations
-Identification of levers in daily life tools

Simple lever setup
-Masses for loads
-Spring balance
-Ruler
-Calculator
-Machine terminology charts
-Efficiency calculation examples
Various lever examples
-Rulers
-Masses
-Spring balance
-Fulcrum supports
-Lever classification charts
-Daily life lever examples
-Calculator
Pulley blocks
-String
-Pulley arrangements
-Block and tackle setup
-Pulley system diagrams

KLB Secondary Physics Form 3, Pages 108-112
KLB Secondary Physics Form 3, Pages 112-114

Work, Energy, Power and Machines

Inclined Planes and Screws

By the end of the lesson, the learner should be able to:
Understand inclined plane as a machine
-Calculate M.A. and V.R. for inclined planes
-Analyze screw as an inclined plane
-Understand applications of inclined planes
-Solve problems involving inclined planes

In groups, learners are guided to:
Q/A on pulley systems
-Demonstration: moving load up inclined plane
-Measurement of effort and load for inclined plane
-Calculation of M.A. and V.R. for inclined plane
-Discussion on screw as modified inclined plane
-Examples of inclined planes in daily life

Inclined plane setup
-Trolley or wooden block
-Spring balance
-Measuring tape
-Protractor
-Calculator
-Screw examples
-Various inclined plane models

KLB Secondary Physics Form 3, Pages 114-115

Work, Energy, Power and Machines

Gears and Hydraulic Systems

By the end of the lesson, the learner should be able to:
Understand gear systems and their operation
-Calculate V.R. for gear systems
-Explain hydraulic lift principle
-Apply Pascal's principle to hydraulic systems
-Calculate M.A. and V.R. for hydraulic systems

In groups, learners are guided to:
Review inclined planes through Q/A
-Demonstration: gear system operation
-Calculation of gear ratios and V.R.
-Explanation of hydraulic lift principle
-Demonstration: Pascal's principle using syringes
-Calculation of hydraulic system parameters

Gear wheels
-Bicycle for gear demonstration
-Syringes of different sizes
-Water
-Tubes
-Calculator
-Hydraulic system diagrams
-Gear ratio charts

KLB Secondary Physics Form 3, Pages 116-119

Work, Energy, Power and Machines

Efficiency of Machines

By the end of the lesson, the learner should be able to:
Understand factors affecting machine efficiency
-Calculate efficiency using different methods
-Investigate efficiency of various machines
-Understand energy losses in machines
-Discuss methods to improve efficiency

In groups, learners are guided to:
Q/A on gears and hydraulic systems
-Investigation: efficiency of pulley system
-Discussion on factors causing energy losses
-Measurement of input and output work
-Calculation of efficiency for different machines
-Discussion on improving machine efficiency

Various machines for testing
-Spring balances
-Measuring tape
-Stopwatch
-Calculator
-Efficiency measurement setup
-Lubricants for demonstration

KLB Secondary Physics Form 3, Pages 120-123

Current Electricity (II)

Electric Current and Measurement

By the end of the lesson, the learner should be able to:
Define electric current and state its SI unit
-Understand conventional current flow
-Use ammeters correctly to measure current
-Read ammeter scales accurately
-Understand current as rate of flow of charge

In groups, learners are guided to:
Q/A review on basic electricity from Form 2
-Definition of electric current and conventional flow
-Demonstration: proper ammeter connection in series
-Practice reading different ammeter scales
-Discussion on digital vs analogue meters
-Safety precautions when using electrical equipment

Ammeters (analogue and digital)
-Dry cells
-Connecting wires
-Bulbs
-Switches
-Ammeter scale charts
-Safety equipment

KLB Secondary Physics Form 3, Pages 126-130

Current Electricity (II)

Series and Parallel Circuits - Current Distribution
Potential Difference and Voltage Measurement

By the end of the lesson, the learner should be able to:
Investigate current in series circuits
-Investigate current in parallel circuits
-Apply Kirchhoff's current law
-Understand current division in parallel circuits
-Solve problems involving current distribution

In groups, learners are guided to:
Review ammeter usage through Q/A
-Experiment: measuring current in series circuit
-Experiment: measuring current in parallel circuit
-Analysis of current readings and patterns
-Statement of Kirchhoff's current law
-Problem-solving on current distribution

Multiple ammeters
-Bulbs
-Connecting wires
-Dry cells
-Switches
-Circuit boards
-Calculator
-Current distribution worksheets
Voltmeters (analogue and digital)
-Resistors
-Voltmeter scale charts
-Work and charge demonstration materials

KLB Secondary Physics Form 3, Pages 130-133

Current Electricity (II)

Series and Parallel Circuits - Voltage Distribution

By the end of the lesson, the learner should be able to:
Investigate voltage in series circuits
-Investigate voltage in parallel circuits
-Apply Kirchhoff's voltage law
-Understand voltage division in series circuits
-Solve problems involving voltage distribution

In groups, learners are guided to:
Review voltage measurement through Q/A
-Experiment: measuring voltage across series components
-Experiment: measuring voltage across parallel components
-Analysis of voltage readings and patterns
-Statement of Kirchhoff's voltage law
-Problem-solving on voltage distribution

Multiple voltmeters
-Various resistors
-Connecting wires
-Dry cells
-Switches
-Circuit boards
-Calculator
-Voltage distribution worksheets

KLB Secondary Physics Form 3, Pages 130-133

Current Electricity (II)

Ohm's Law - Investigation and Verification
Electrical Resistance and Ohm's Law Applications

By the end of the lesson, the learner should be able to:
State Ohm's law
-Investigate relationship between voltage and current
-Plot V-I graphs for ohmic conductors
-Verify Ohm's law experimentally
-Understand conditions for Ohm's law validity
Define electrical resistance and its SI unit
-Apply Ohm's law to calculate V, I, and R
-Understand the relationship R = V/I
-Solve problems using Ohm's law
-Convert between different units of resistance

In groups, learners are guided to:
Q/A on voltage distribution
-Experiment: varying voltage and measuring current through resistor
-Data collection and table completion
-Plotting V-I graph and analyzing slope
-Statement and verification of Ohm's law
-Discussion on temperature and other conditions
Review Ohm's law investigation through Q/A
-Definition of electrical resistance as V/I ratio
-Worked examples applying Ohm's law triangle
-Unit conversions: Ω, kΩ, MΩ
-Problem-solving session on Ohm's law calculations
-Discussion on factors affecting resistance

Rheostat
-Ammeter
-Voltmeter
-Resistor coils
-Connecting wires
-Dry cells
-Graph paper
-Calculator
-Ruler
Calculator
-Ohm's law triangle charts
-Resistor color code charts
-Various resistors
-Multimeter
-Problem worksheets
-Unit conversion charts

KLB Secondary Physics Form 3, Pages 131-135

Current Electricity (II)

Ohmic and Non-Ohmic Conductors

By the end of the lesson, the learner should be able to:
Distinguish between ohmic and non-ohmic conductors
-Investigate V-I characteristics of different materials
-Understand why some materials don't obey Ohm's law
-Analyze V-I graphs for various conductors
-Identify practical applications of non-ohmic conductors

In groups, learners are guided to:
Q/A on Ohm's law applications
-Experiment: V-I characteristics of filament bulb
-Experiment: V-I characteristics of diode
-Comparison of different V-I graph shapes
-Discussion on temperature effects on resistance
-Applications of non-ohmic conductors

Filament bulbs
-Diodes
-Thermistors
-LDR
-Ammeter
-Voltmeter
-Rheostat
-Graph paper
-Various conductors for testing

KLB Secondary Physics Form 3, Pages 134-135

Current Electricity (II)

Types of Resistors and Their Applications

By the end of the lesson, the learner should be able to:
Identify different types of resistors
-Understand fixed and variable resistors
-Read resistor color codes
-Understand applications of special resistors
-Use rheostats and potentiometers

In groups, learners are guided to:
Review ohmic vs non-ohmic conductors through Q/A
-Identification of resistor types: carbon, wire-wound, variable
-Practice reading resistor color codes
-Demonstration: rheostat and potentiometer operation
-Discussion on thermistors and LDR applications
-Practical applications in circuits

Various resistor types
-Color code charts
-Rheostat
-Potentiometer
-Thermistor
-LDR
-Multimeter
-Circuit boards
-Application examples

KLB Secondary Physics Form 3, Pages 135-140

Current Electricity (II)

Measurement of Resistance - Voltmeter-Ammeter Method
Wheatstone Bridge Method

By the end of the lesson, the learner should be able to:
Describe voltmeter-ammeter method
-Set up circuits for resistance measurement
-Calculate resistance from V and I readings
-Understand limitations of the method
-Analyze experimental errors

In groups, learners are guided to:
Q/A on resistor types
-Setup of voltmeter-ammeter circuit
-Measurement of voltage and current for unknown resistor
-Calculation of resistance using R = V/I
-Discussion on measurement errors and accuracy
-Comparison with multimeter readings

Unknown resistors
-Voltmeter
-Ammeter
-Rheostat
-Connecting wires
-Dry cells
-Switches
-Calculator
-Multimeter for comparison
Wheatstone bridge apparatus
-Galvanometer
-Known resistors
-Unknown resistors
-Battery
-Bridge equation charts

KLB Secondary Physics Form 3, Pages 140-142

Current Electricity (II)

Resistors in Series - Theory and Calculations
Resistors in Parallel - Theory and Calculations

By the end of the lesson, the learner should be able to:
Derive formula for resistors in series
-Calculate total resistance for series combination
-Understand current and voltage in series circuits
-Solve problems involving series resistors
-Apply series resistance in circuit analysis
Derive formula for resistors in parallel
-Calculate total resistance for parallel combination
-Understand current and voltage in parallel circuits
-Solve problems involving parallel resistors
-Apply parallel resistance in circuit analysis

In groups, learners are guided to:
Q/A on resistance measurement methods
-Derivation of Rs = R₁ + R₂ + R₃...
-Demonstration: measuring total resistance of series combination
-Analysis of current (same) and voltage (divided) in series
-Worked examples on series resistance calculations
-Problem-solving session
Review series resistance through Q/A
-Derivation of 1/Rp = 1/R₁ + 1/R₂ + 1/R₃...
-Demonstration: measuring total resistance of parallel combination
-Analysis of voltage (same) and current (divided) in parallel
-Worked examples on parallel resistance calculations
-Problem-solving session

Resistors of known values
-Multimeter
-Connecting wires
-Circuit boards
-Calculator
-Series circuit diagrams
-Problem worksheets
Resistors of known values
-Multimeter
-Connecting wires
-Circuit boards
-Calculator
-Parallel circuit diagrams
-Problem worksheets

KLB Secondary Physics Form 3, Pages 144-147
KLB Secondary Physics Form 3, Pages 147-150

Current Electricity (II)

Mixed Circuits - Series-Parallel Combinations

By the end of the lesson, the learner should be able to:
Analyze circuits with series-parallel combinations
-Apply reduction techniques to complex circuits
-Calculate total resistance of mixed circuits
-Determine current and voltage in different branches
-Solve complex circuit problems

In groups, learners are guided to:
Q/A on parallel resistance
-Introduction to mixed circuit analysis techniques
-Step-by-step reduction of complex circuits
-Worked examples on series-parallel combinations
-Problem-solving on mixed circuits
-Discussion on circuit analysis strategies

Various resistors
-Circuit boards
-Connecting wires
-Multimeter
-Calculator
-Complex circuit diagrams
-Step-by-step analysis charts

KLB Secondary Physics Form 3, Pages 150-153

Current Electricity (II)

Electromotive Force (EMF) and Terminal Voltage

By the end of the lesson, the learner should be able to:
Define electromotive force (EMF)
-Distinguish between EMF and terminal voltage
-Understand the concept of lost voltage
-Relate EMF to work done by the cell
-Measure EMF using high resistance voltmeter

In groups, learners are guided to:
Review mixed circuits through Q/A
-Definition of EMF as work done per unit charge
-Demonstration: measuring EMF with open circuit
-Comparison of EMF and terminal voltage under load
-Discussion on energy conversion in cells
-Measurement techniques for EMF

High resistance voltmeter
-Various cells
-Switches
-Resistors
-Connecting wires
-EMF measurement setup
-Energy conversion charts

KLB Secondary Physics Form 3, Pages 150-152

Current Electricity (II)

Internal Resistance of Cells
Cells in Series and Parallel

By the end of the lesson, the learner should be able to:
Define internal resistance
-Understand the relationship E = V + Ir
-Calculate internal resistance experimentally
-Understand factors affecting internal resistance
-Apply internal resistance in circuit calculations

In groups, learners are guided to:
Q/A on EMF concepts
-Introduction to internal resistance concept
-Derivation of E = V + Ir relationship
-Experiment: measuring internal resistance using different loads
-Plotting E vs R graph to find internal resistance
-Discussion on factors affecting internal resistance

Various cells
-Resistors of different values
-Voltmeter
-Ammeter
-Connecting wires
-Graph paper
-Calculator
-Internal resistance apparatus
Multiple identical cells
-Resistors
-Cell combination diagrams
-Problem worksheets

KLB Secondary Physics Form 3, Pages 150-153

Current Electricity (II)
Electrostatics II

Advanced Circuit Analysis and Problem Solving
Electric field patterns and charge distribution
Lightning arrestor and capacitance introduction

By the end of the lesson, the learner should be able to:
Apply Kirchhoff's laws to complex circuits
-Solve circuits with multiple sources
-Analyze circuits with internal resistance
-Use systematic approaches to circuit problems
-Integrate all electricity concepts
Define electric field and electric field lines
- Demonstrate field patterns using chalk dust method
- Describe charge distribution on spherical and pear-shaped conductors
- Use proof-plane and electroscope to test charge distribution

In groups, learners are guided to:
Q/A on cell combinations
-Application of Kirchhoff's current and voltage laws
-Systematic approach to complex circuit analysis
-Worked examples with multiple EMF sources
-Problem-solving session covering all electricity topics
-Discussion on practical circuit applications
Q/A on electrostatics basics from Form 2
- Experiment using chalk dust in castor oil to show field patterns
- Investigation of charge distribution using proof-plane
- Observation of electroscope deflections at different conductor points

Complex circuit examples
-Calculator
-Circuit analysis worksheets
-Multiple EMF sources
-Various resistors
-Comprehensive problem sets
-Kirchhoff's law charts
High voltage source, Wire electrodes, Petri-dish, Castor oil, Chalk dust, Spherical and pear-shaped conductors, Proof-plane, Gold-leaf electroscope
Wind-mill model, Point charges, Lightning arrestor photos, Parallel-plate capacitors, Battery, Voltmeter, Milliammeter

KLB Secondary Physics Form 3, Pages 126-153
KLB Secondary Physics Form 3, Pages 177-181

Electrostatics II

Factors affecting capacitance and types of capacitors
Capacitors in series and parallel
Energy stored in capacitors

By the end of the lesson, the learner should be able to:
Investigate effect of plate separation, area and dielectric on capacitance
- Derive capacitance formula C = εA/d
- Describe paper, electrolytic and variable capacitors
- Explain construction principles

In groups, learners are guided to:
Experiment varying plate separation and area
- Investigation using different dielectric materials
- Mathematical derivation of capacitance formula
- Examination of different capacitor types and their construction

Aluminium plates, Various dielectric materials, Electroscope, Paper capacitors, Electrolytic capacitors, Variable air capacitors, Measuring instruments
Capacitors of different values, Voltmeters, Ammeters, Battery, Connecting wires, Calculators, Circuit boards
Charged capacitors, Energy calculation worksheets, Graphing materials, Calculators, Safety equipment

KLB Secondary Physics Form 3, Pages 185-188

Electrostatics II

Complex capacitor problems
Applications of capacitors

By the end of the lesson, the learner should be able to:
Solve problems involving mixed series and parallel combinations
- Calculate charges, voltages and energies in complex circuits
- Apply energy conservation principles
- Analyze capacitor charging and discharging

In groups, learners are guided to:
Problem solving with complex capacitor networks
- Analysis of charging and discharging processes
- Energy transfer calculations
- Graph interpretation of charging curves

Complex circuit diagrams, Advanced problem worksheets, Graphing materials, Calculators, Past examination papers
Circuit diagrams, Smoothing circuit demo, Radio tuning circuits, Camera flash unit, Revision charts, Past examination papers

KLB Secondary Physics Form 3, Pages 188-193

Heating Effect of Electric Current

Introduction to heating effect
Factors affecting heat produced - current and time
Factors affecting heat produced - resistance

By the end of the lesson, the learner should be able to:
Define heating effect of electric current
- Explain mechanism of heat production in conductors
- Investigate effect of current on resistance wire
- Observe temperature changes in conductors

In groups, learners are guided to:
Q/A on electric current from previous units
- Experiment investigating effect of current on coil temperature
- Observation of heating in different parts of circuit
- Discussion on electron collision mechanism

Battery, Resistance wire coils, Ammeter, Variable resistor, Thermometer, Stopwatch, Connecting wires
Resistance coils, Variable resistor, Ammeter, Thermometer, Stopwatch, Graph paper, Different current values
Coils of different resistance, Ammeter, Thermometer, Measuring instruments, Stopwatch, Calculation worksheets

KLB Secondary Physics Form 3, Pages 195-197

Heating Effect of Electric Current

Joule's law and electrical energy
Electrical power and energy calculations
Applications - electrical lighting and heating devices
Electrical safety - fuses and circuit protection

By the end of the lesson, the learner should be able to:
State Joule's law of heating
- Derive H = I²Rt = VIt = V²t/R
- Calculate electrical energy and power
- Solve numerical problems on heating calculations
Describe working of filament lamp
- Explain choice of tungsten for filaments
- Describe working of electric iron, kettle and heaters
- Compare energy saving bulbs

In groups, learners are guided to:
Discussion on Joule's heating law
- Mathematical derivations of heating formulas
- Problem solving on energy calculations
- Practical applications of heating law
Discussion on filament lamp construction
- Analysis of heating device designs
- Examination of actual heating appliances
- Efficiency comparisons

Formula charts, Calculators, Problem worksheets, Electrical devices for analysis
Calculators, Unit conversion charts, Household appliance ratings, Electricity bills, Problem sets
Filament lamps, Electric iron, Electric kettle, Heating elements, Energy saving bulbs, Appliance diagrams
Various fuses, Fuse holders, Circuit diagrams, Safety equipment demonstrations, Rating calculations

KLB Secondary Physics Form 3, Pages 200-201
KLB Secondary Physics Form 3, Pages 202-203

Heating Effect of Electric Current

Efficiency calculations and motor problems
Series and parallel heating circuits

By the end of the lesson, the learner should be able to:
Calculate efficiency of electrical devices
- Solve problems involving motors and mechanical work
- Analyze power input vs power output
- Calculate overall efficiency in systems

In groups, learners are guided to:
Problem solving on device efficiency
- Motor efficiency calculations
- Analysis of energy conversions
- Real-world efficiency problems

Motor specifications, Efficiency calculation worksheets, Power meters, Mechanical loading systems
Resistors in circuits, Ammeters, Voltmeters, Power calculation sheets, Circuit boards

KLB Secondary Physics Form 3, Pages 201-204