Work, Energy, Power and Machines

Sources of Energy
Forms of Energy
Energy Transformation and Conservation

By the end of the lesson, the learner should be able to:
Identify different sources of energy
-Distinguish between renewable and non-renewable energy sources
-Classify energy sources into appropriate categories
-Discuss advantages and disadvantages of different energy sources
-Understand energy crisis and conservation needs
Define different forms of energy
-Identify chemical, mechanical, heat, electrical, and wave energy
-Give examples of each form of energy
-Understand energy exists in various forms
-Relate forms of energy to daily experiences

Q/A on energy experiences in daily life
-Discussion on various energy sources students know
-Classification activity: renewable vs non-renewable
-Group work on energy source advantages/disadvantages
-Presentation on local energy sources in Kenya
-Discussion on energy conservation importance
Review energy sources through Q/A
-Introduction to different forms of energy
-Demonstration: chemical energy in battery, mechanical energy in moving objects
-Discussion on heat energy from friction
-Examples of electrical energy in appliances
-Identification of wave energy: light, sound

Charts showing energy sources
-Pictures of solar panels, wind mills
-Samples: coal, wood, batteries
-Energy source classification cards
-Local energy examples
-Conservation posters
Battery and bulb
-Moving trolley
-Rubbing blocks for friction
-Electrical appliances
-Tuning fork
-Torch
-Energy forms charts
-Real objects showing energy forms
Dynamo
-Battery
-Solar cell (if available)
-Charts showing energy transformations
-Transducer examples
-Energy flow diagrams
-Hydroelectric model setup

KLB Secondary Physics Form 3, Pages 93-95
KLB Secondary Physics Form 3, Pages 95-96

Work, Energy, Power and Machines

Work and its Calculation

By the end of the lesson, the learner should be able to:
Define work in scientific terms
-State the condition for work to be done
-Calculate work using W = F × d
-Understand work as a scalar quantity
-Solve problems involving work calculations

Review energy transformations through Q/A
-Definition of work with emphasis on force and displacement
-Demonstration: lifting objects, pushing trolleys
-Worked examples on work calculations
-Discussion on when no work is done
-Problem-solving session on work calculations

Spring balance
-Masses
-Trolley
-Measuring tape
-Calculator
-Force and displacement demonstrations
-Worked examples charts
-Problem worksheets

KLB Secondary Physics Form 3, Pages 96-99

Work, Energy, Power and Machines

Work with Variable Forces

By the end of the lesson, the learner should be able to:
Calculate work done by variable forces
-Interpret force-distance graphs
-Find work done using area under graphs
-Understand positive and negative work
-Apply graphical methods to work calculations

Q/A review on work calculations
-Introduction to variable forces
-Plotting force-distance graphs
-Demonstration: stretching spring with varying force
-Calculation of areas under graphs
-Worked examples with triangular and trapezoidal areas

Graph paper
-Springs
-Force meter
-Ruler
-Calculator
-Force-distance graph examples
-Different shaped area examples
-Demonstration springs

KLB Secondary Physics Form 3, Pages 99-100

Work, Energy, Power and Machines

Gravitational Potential Energy

By the end of the lesson, the learner should be able to:
Define gravitational potential energy
-Derive P.E. = mgh
-Calculate potential energy at different heights
-Understand reference levels for potential energy
-Solve problems involving potential energy

Review variable force work through Q/A
-Demonstration: lifting objects to different heights
-Derivation of P.E. = mgh
-Discussion on choice of reference level
-Worked examples on potential energy calculations
-Problem-solving session with gravitational P.E.

Masses of different sizes
-Measuring tape
-Spring balance
-Calculator
-Height measurement setup
-Worked examples
-Gravitational P.E. charts

KLB Secondary Physics Form 3, Pages 100-102

Work, Energy, Power and Machines

Kinetic Energy
Conservation of Mechanical Energy
Power and its Applications

By the end of the lesson, the learner should be able to:
Define kinetic energy
-Derive K.E. = ½mv²
-Calculate kinetic energy of moving objects
-Understand relationship between work and kinetic energy
-Apply work-energy theorem
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

Q/A on potential energy concepts
-Demonstration: moving trolleys at different speeds
-Derivation of K.E. = ½mv² using work-energy theorem
-Worked examples on kinetic energy calculations
-Discussion on work-energy theorem
-Problem-solving session on kinetic energy
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

Trolleys
-Stopwatch
-Measuring tape
-Spring balance
-Calculator
-Kinetic energy demonstration setup
-Speed measurement apparatus
Simple pendulum setup
-Masses
-Pendulum energy charts
-Conservation examples
-String and bob
Stopwatch
-Measuring tape
-Spring balance
-Calculator
-Electrical appliances for power ratings
-Stairs for practical work
-Power calculation charts

KLB Secondary Physics Form 3, Pages 102-105
KLB Secondary Physics Form 3, Pages 106-108

Work, Energy, Power and Machines

Simple Machines - Introduction and Terminology

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

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%

Simple lever setup
-Masses for loads
-Spring balance
-Ruler
-Calculator
-Machine terminology charts
-Efficiency calculation examples

KLB Secondary Physics Form 3, Pages 108-112

Work, Energy, Power and Machines

Levers - Types and Applications

By the end of the lesson, the learner should be able to:
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

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

Various lever examples
-Rulers
-Masses
-Spring balance
-Fulcrum supports
-Lever classification charts
-Daily life lever examples
-Calculator

KLB Secondary Physics Form 3, Pages 112-114

Work, Energy, Power and Machines

Pulleys - Fixed and Movable
Inclined Planes and Screws

By the end of the lesson, the learner should be able to:
Understand operation of fixed and movable pulleys
-Calculate M.A. and V.R. for different pulley systems
-Analyze block and tackle arrangements
-Solve problems involving pulley systems
-Understand advantages of pulley systems

Review lever types through Q/A
-Demonstration: fixed pulley operation
-Demonstration: single movable pulley
-Analysis of block and tackle systems
-Calculation of M.A. and V.R. for different arrangements
-Problem-solving on pulley systems

Pulley blocks
-String
-Masses
-Spring balance
-Pulley arrangements
-Block and tackle setup
-Calculator
-Pulley system diagrams
Inclined plane setup
-Trolley or wooden block
-Measuring tape
-Protractor
-Screw examples
-Various inclined plane models

KLB Secondary Physics Form 3, Pages 115-120

Work, Energy, Power and Machines

Gears and Hydraulic Systems
Efficiency of Machines

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
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

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
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

Gear wheels
-Bicycle for gear demonstration
-Syringes of different sizes
-Water
-Tubes
-Calculator
-Hydraulic system diagrams
-Gear ratio charts
Various machines for testing
-Spring balances
-Measuring tape
-Stopwatch
-Calculator
-Efficiency measurement setup
-Lubricants for demonstration

KLB Secondary Physics Form 3, Pages 116-119
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

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

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

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

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
Types of Resistors and Their Applications

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

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

KLB Secondary Physics Form 3, Pages 134-135

Current Electricity (II)

Measurement of Resistance - Voltmeter-Ammeter 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

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

KLB Secondary Physics Form 3, Pages 140-142

Current Electricity (II)

Wheatstone Bridge Method

By the end of the lesson, the learner should be able to:
Understand the principle of Wheatstone bridge
-Set up Wheatstone bridge circuit
-Balance the bridge for resistance measurement
-Calculate unknown resistance using bridge equation
-Appreciate accuracy of Wheatstone bridge method

Review voltmeter-ammeter method through Q/A
-Introduction to Wheatstone bridge principle
-Demonstration of bridge balance condition
-Setup and operation of Wheatstone bridge
-Calculation using R₁/R₂ = R₃/R₄
-Comparison of accuracy with other methods

Wheatstone bridge apparatus
-Galvanometer
-Known resistors
-Unknown resistors
-Connecting wires
-Battery
-Calculator
-Bridge equation charts

KLB Secondary Physics Form 3, Pages 142-144

Current Electricity (II)

Resistors in Series - Theory and Calculations
Resistors in Parallel - Theory and Calculations
Mixed Circuits - Series-Parallel Combinations

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

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
Various resistors
-Complex circuit diagrams
-Step-by-step analysis charts

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

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

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

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

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

KLB Secondary Physics Form 3, Pages 150-153

Current Electricity (II)

Cells in Series and Parallel

By the end of the lesson, the learner should be able to:
Analyze cells connected in series
-Analyze cells connected in parallel
-Calculate total EMF and internal resistance
-Understand advantages of different connections
-Solve problems involving cell combinations

Review internal resistance through Q/A
-Analysis of identical cells in series connection
-Analysis of identical cells in parallel connection
-Calculation of equivalent EMF and internal resistance
-Discussion on practical applications and advantages
-Problem-solving on cell combinations

Multiple identical cells
-Connecting wires
-Voltmeter
-Ammeter
-Resistors
-Calculator
-Cell combination diagrams
-Problem worksheets

KLB Secondary Physics Form 3, Pages 152-153

Current Electricity (II)
Waves II
Waves II

Advanced Circuit Analysis and Problem Solving
Properties of waves
Reflection of waves
Refraction of waves
Diffraction of waves

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
Describe refraction when waves change medium
- Explain change in wavelength and speed
- Demonstrate refraction using shallow and deep regions
- State that frequency remains constant

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 refraction basics
- Experiment using glass plate to create shallow region
- Observation of wavefront spacing changes
- Discussion on speed and wavelength changes

Complex circuit examples
-Calculator
-Circuit analysis worksheets
-Multiple EMF sources
-Various resistors
-Comprehensive problem sets
-Kirchhoff's law charts
Ripple tank, Straight vibrator, Water, Rulers, Stroboscope, Charts on wave properties
Ripple tank, Plane wave generator, Curved and straight reflectors, Graph paper, Pencils
Ripple tank, Glass plates, Water, Rulers for measurement, Frequency generator
Ripple tank, Barriers with gaps, Various gap sizes, Measuring instruments, Wave generator

KLB Secondary Physics Form 3, Pages 126-153
KLB Secondary Physics Form 3, Pages 161-163

Waves II

Interference patterns
Constructive and destructive interference
Stationary waves formation

By the end of the lesson, the learner should be able to:
Define interference and superposition principle
- Explain constructive and destructive interference
- Describe formation of interference patterns
- Calculate path differences

Demonstration using two coherent sources
- Construction of interference patterns on paper
- Observation of nodal and antinodal lines
- Discussion on coherent sources

Two-point sources, Graph paper, Compass, Rulers, Ripple tank setup, Audio frequency generator
Two loudspeakers, Audio generator, Microphone, Sound level meter, Connecting wires
Tuning fork, String, Pulley, Weights, Stroboscope, Measuring tape, Retort stands

KLB Secondary Physics Form 3, Pages 165-167

Waves II

Modes of vibration in strings
Vibrating air columns - closed pipes

By the end of the lesson, the learner should be able to:
Derive expressions for fundamental frequency
- Explain harmonics and overtones
- Calculate frequencies of overtones
- Demonstrate different modes

Discussion on fundamental and overtone frequencies
- Mathematical derivation of frequency formulas
- Practical demonstration of string vibrations
- Problem solving

Sonometer, Tuning forks, Weights, Measuring instruments, Calculator, Formula charts
Closed pipes of various lengths, Tuning forks, Water, Measuring cylinders, Resonance tubes

KLB Secondary Physics Form 3, Pages 170-172

Waves II
Electrostatics II

Vibrating air columns - open pipes
Electric field patterns and charge distribution

By the end of the lesson, the learner should be able to:
Compare open and closed pipe resonance
- Derive frequency formulas for open pipes
- Explain harmonic series differences
- Solve numerical problems

Experiment with open pipe resonance
- Comparison with closed pipe results
- Mathematical problem solving
- Summary of all wave phenomena

Open pipes, Tuning forks, Sound level meters, Calculators, Summary charts, Past papers
High voltage source, Wire electrodes, Petri-dish, Castor oil, Chalk dust, Spherical and pear-shaped conductors, Proof-plane, Gold-leaf electroscope

KLB Secondary Physics Form 3, Pages 174-176

Electrostatics II

Lightning arrestor and capacitance introduction
Factors affecting capacitance and types of capacitors
Capacitors in series and parallel
Energy stored in capacitors
Complex capacitor problems

By the end of the lesson, the learner should be able to:
Explain working principle of lightning arrestor
- Describe charge concentration at sharp points
- Define capacitance and state SI units
- Describe parallel-plate capacitor structure
Derive effective capacitance for series combination
- Derive effective capacitance for parallel combination
- Explain charge and voltage relationships
- Calculate individual charges and voltages

Demonstration of charge concentration at points using wind-mill experiment
- Discussion on lightning protection applications
- Introduction to capacitance concept
- Demonstration of capacitor charging process
Mathematical derivation of series formula (1/C = 1/C₁ + 1/C₂)
- Mathematical derivation of parallel formula (C = C₁ + C₂)
- Problem solving with capacitor combinations
- Practical verification using circuits

Wind-mill model, Point charges, Lightning arrestor photos, Parallel-plate capacitors, Battery, Voltmeter, Milliammeter
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
Complex circuit diagrams, Advanced problem worksheets, Graphing materials, Calculators, Past examination papers

KLB Secondary Physics Form 3, Pages 181-185
KLB Secondary Physics Form 3, Pages 188-191

Electrostatics II
Heating Effect of Electric Current

Applications of capacitors
Introduction to heating effect

By the end of the lesson, the learner should be able to:
Explain use in rectification and smoothing circuits
- Describe applications in tuning circuits
- State use in delay circuits and camera flash
- Solve comprehensive numerical problems on all topics

Discussion on practical applications in electronics
- Demonstration of smoothing circuits
- Explanation of tuning and delay functions
- Comprehensive revision and problem solving covering all electrostatics topics

Circuit diagrams, Smoothing circuit demo, Radio tuning circuits, Camera flash unit, Revision charts, Past examination papers
Battery, Resistance wire coils, Ammeter, Variable resistor, Thermometer, Stopwatch, Connecting wires

KLB Secondary Physics Form 3, Pages 192-193

Heating Effect of Electric Current

Factors affecting heat produced - current and time
Factors affecting heat produced - resistance
Joule's law and electrical energy

By the end of the lesson, the learner should be able to:
Investigate relationship between heat produced and current
- Investigate relationship between heat produced and time
- Plot graphs of temperature vs current² and time
- State H ∝ I²t relationship

Experiment varying current and measuring temperature change
- Investigation of heating time relationship
- Data collection and graph plotting
- Mathematical analysis of relationships

Resistance coils, Variable resistor, Ammeter, Thermometer, Stopwatch, Graph paper, Different current values
Coils of different resistance, Ammeter, Thermometer, Measuring instruments, Stopwatch, Calculation worksheets
Formula charts, Calculators, Problem worksheets, Electrical devices for analysis

KLB Secondary Physics Form 3, Pages 197-199

Heating Effect of Electric Current

Electrical power and energy calculations
Applications - electrical lighting and heating devices

By the end of the lesson, the learner should be able to:
Define electrical power P = VI = I²R = V²/R
- Calculate electrical energy W = Pt
- Convert between different units (J, kWh)
- Solve complex power problems

Derivation of electrical power formulas
- Energy unit conversions
- Problem solving on household appliances
- Cost calculations for electrical consumption

Calculators, Unit conversion charts, Household appliance ratings, Electricity bills, Problem sets
Filament lamps, Electric iron, Electric kettle, Heating elements, Energy saving bulbs, Appliance diagrams

KLB Secondary Physics Form 3, Pages 201-202

Heating Effect of Electric Current
Quantity of Heat

Electrical safety - fuses and circuit protection
Efficiency calculations and motor problems
Series and parallel heating circuits
Heat capacity and specific heat capacity
Determination of specific heat capacity - method of mixtures for solids

By the end of the lesson, the learner should be able to:
Explain working principle of fuses
- Calculate appropriate fuse ratings
- Describe safety measures in electrical installations
- Analyze circuit protection methods
Define heat capacity and specific heat capacity
- State SI units for both quantities
- Distinguish between heat capacity and specific heat capacity
- Use formula Q = mcθ in simple calculations

Demonstration of fuse operation
- Calculation of fuse ratings for appliances
- Discussion on electrical safety
- Analysis of circuit protection devices
Q/A on heat concepts from previous studies
- Discussion on definitions and units
- Comparison of heat capacity vs specific heat capacity
- Simple problem solving using Q = mcθ formula

Various fuses, Fuse holders, Circuit diagrams, Safety equipment demonstrations, Rating calculations
Motor specifications, Efficiency calculation worksheets, Power meters, Mechanical loading systems
Resistors in circuits, Ammeters, Voltmeters, Power calculation sheets, Circuit boards
Charts on heat definitions, Calculators, Simple problem worksheets, Various materials for comparison
Metal blocks, Beakers, Water, Thermometers, Weighing balance, Heat source, Well-lagged calorimeter, Stirrer

KLB Secondary Physics Form 3, Pages 203-204
KLB Secondary Physics Form 3, Pages 206-209

Quantity of Heat

Determination of specific heat capacity - electrical method
Specific heat capacity of liquids and continuous flow method
Change of state and latent heat concepts

By the end of the lesson, the learner should be able to:
Describe electrical method for solids
- Perform electrical heating experiment
- Calculate electrical energy supplied
- Determine specific heat capacity using electrical method

Experiment using electrical heating of metal block
- Measurement of voltage, current and time
- Calculation of electrical energy supplied
- Determination of specific heat capacity

Metal cylinder with heater, Voltmeter, Ammeter, Thermometer, Stopwatch, Insulating materials, Power supply
Calorimeter, Electrical heater, Water, Measuring instruments, Continuous flow apparatus diagram, Problem sets
Naphthalene, Test tubes, Thermometer, Stopwatch, Graph paper, Heat source, Cooling apparatus

KLB Secondary Physics Form 3, Pages 212-214

Quantity of Heat

Specific latent heat of fusion
Specific latent heat of vaporization

By the end of the lesson, the learner should be able to:
Define specific latent heat of fusion
- Determine latent heat of ice by method of mixtures
- Perform electrical method for latent heat
- Calculate latent heat from experimental data

Method of mixtures experiment using ice and warm water
- Electrical method using ice and immersion heater
- Heat balance calculations
- Determination of specific latent heat values

Ice, Calorimeter, Thermometer, Electrical heater, Filter funnels, Beakers, Measuring cylinders
Steam generator, Condenser, Calorimeter, Electrical heater, Measuring instruments, Safety equipment

KLB Secondary Physics Form 3, Pages 220-223

Quantity of Heat

Effects of pressure and impurities on melting and boiling points
Evaporation and cooling effects

By the end of the lesson, the learner should be able to:
Investigate effect of pressure on melting point of ice
- Demonstrate regelation phenomenon
- Investigate effect of pressure on boiling point
- Explain effect of impurities on phase transition temperatures

Regelation experiment with ice and wire
- Pressure effect on boiling point using flask
- Salt solution boiling point investigation
- Discussion on pressure cooker working

Ice blocks, Weighted wire, Round-bottomed flask, Thermometer, Salt solutions, Pressure cooker model
Various liquids, Beakers, Fans, Thermometers, Ether, Test tubes, Humidity measuring devices

KLB Secondary Physics Form 3, Pages 227-230