Force and Energy

Transformation of Energy - Forms of energy in nature
Transformation of Energy - Renewable and non-renewable energy sources
Transformation of Energy - Energy transformation is the process of changing one form of energy to another

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

- Identify forms of energy in nature: light, heat, potential, kinetic, gravitational, electrical, sound, chemical and nuclear energy
- Define energy as the ability to do work
- Show interest in relating different forms of energy to everyday experiences

- Define energy transformation as the process of changing one form of energy to another
- Give examples of energy transformations in nature
- Show interest in identifying energy transformations in everyday situations

In groups, learners are guided to:

- Study pictures in Figure 3.1 showing different sources and forms of energy
- Discuss the meaning of energy and the different forms it takes
- Use a digital device or print media to search for information on forms of energy in nature

- Discuss examples of energy transformations such as food keeping the body warm and sound from a falling fruit
- Discuss energy transformations: potential to kinetic in a waterfall, chemical to heat in burning
- State the law of conservation of energy

What are the different forms of energy found in nature?
How does energy change from one form to another in nature?

Grade 8 Integrated Science Learner's Book
Charts showing forms of energy
Internet access
Reference books
Table 3.1 energy sources chart
Grade 8 Integrated Science Learner's Book
Reference books
Internet access

Observation Oral questions
Oral questions Oral questions

Force and Energy

Transformation of Energy - Demonstrating energy transformations in a falling object
Transformation of Energy - Energy transformations in a turbine and falling water

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

- Demonstrate energy transformation in a falling object from potential to kinetic energy
- Explain the energy transformations that occur in a swinging pendulum
- Appreciate that energy is conserved during transformation

In groups, learners are guided to:

- Carry out an activity to demonstrate energy transformation in a falling object
- Study Figure 3.4 showing children playing a swinging game
- Discuss the energy transformations at different points of the swing

How does energy transform in a falling object or swinging pendulum?

Grade 8 Integrated Science Learner's Book
Pendulum or swinging equipment
Reference books
Cardboard
Wire
Charts showing turbine

Observation Oral questions

Force and Energy

Transformation of Energy - Making a turbine model
Transformation of Energy - Appliances that rely on energy transformation

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

- Construct a model turbine to demonstrate energy transformation
- Explain the energy transformations observed in the model turbine
- Show interest in practical investigations of energy transformation

In groups, learners are guided to:

- Construct a model turbine using cardboard strips and wire as in Figures 3.7–3.9
- Observe the turbine spinning when water is poured and discuss energy changes
- Present and explain the turbine model to classmates

How can a model turbine be used to demonstrate energy transformation?

Grade 8 Integrated Science Learner's Book
Cardboard strips
Wire
Plastic strip
Water
Charts showing appliances
Actual appliances
Reference books

Observation Presentations

Force and Energy

Transformation of Energy - Energy transformations in specific appliances

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

- Trace the energy transformation chain in a generator, solar panel, radio and electric bulb
- Distinguish between appliances that transform electrical energy to other forms and vice versa
- Appreciate that appliances are designed around energy transformation principles

In groups, learners are guided to:

- Discuss energy transformations in a generator: mechanical → electrical
- Discuss energy transformations in a solar panel: light → electrical
- Discuss energy transformations in a radio: electrical → sound
- Present discussion points to the rest of classmates

How does knowledge of energy transformation explain how electrical appliances work?

Grade 8 Integrated Science Learner's Book
Reference books
Internet access
Table 3.2

Oral questions Written tests

Force and Energy

Transformation of Energy - Safety measures against accidents caused by energy transformation
Transformation of Energy - Safety measures against electrical and sound energy hazards

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

- Describe safety measures to observe against car accidents caused by energy transformation
- Describe safety measures to reduce dangers associated with accidental fire
- Show interest in applying science knowledge to promote personal and community safety

- Describe safety measures to observe against electrical energy hazards
- Describe safety measures to protect hearing from sound energy damage
- Appreciate the importance of safety measures in protecting life and property

In groups, learners are guided to:

- Discuss how kinetic energy in moving vehicles causes accidents and safety measures to prevent them
- Discuss how chemical energy in fuels transforms to heat energy causing fires
- Discuss safety measures: wearing seatbelts, obeying speed limits, using fire extinguishers

- Discuss safety measures against electrical hazards: switching off appliances, avoiding wet hands near electricity
- Discuss safety measures against sound hazards: reducing volume, staying away from loud sounds, using ear protection
- Search for information on electrical and sound safety measures using digital devices

What safety measures should we observe to prevent accidents related to energy transformation?
How can we protect ourselves from hazards caused by electrical and sound energy?

Grade 8 Integrated Science Learner's Book
Internet access
Reference books
Charts

Oral questions Written assignments
Oral questions Written tests

Force and Energy

Transformation of Energy - Safety measures: research and presentation

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

- Research safety measures associated with energy transformation for assigned topics
- Present findings on safety measures related to car accidents, fire, electrical and sound hazards
- Show responsibility in promoting safety awareness among peers

In groups, learners are guided to:

- Use a digital device or print media to research safety measures for assigned energy hazards
- Prepare and present findings to classmates on car accidents, fire, electrical and sound hazards
- Discuss and evaluate the safety measures presented by different groups

How can we use knowledge of energy transformation to promote safety in our community?

Grade 8 Integrated Science Learner's Book
Internet access
Reference books

Presentations Oral questions

Force and Energy

Transformation of Energy - Applications of energy transformation in day-to-day life

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

- Describe applications of energy transformation in day-to-day life
- Give examples of how energy transformation is used in cooking, transport, communication and entertainment
- Appreciate the role of energy transformation in modern life

In groups, learners are guided to:

- Study Figure 3.13 showing applications of energy transformation in daily life
- Discuss applications such as cooking with a gas cooker, charging a phone and driving a car
- Use digital or print media to search for additional applications of energy transformation

How is energy transformation applied to improve our daily lives?

Grade 8 Integrated Science Learner's Book
Charts on energy applications
Internet access
Reference books

Oral questions Written assignments

Force and Energy

Transformation of Energy - Applications of energy transformation in day-to-day life

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

- Describe applications of energy transformation in day-to-day life
- Give examples of how energy transformation is used in cooking, transport, communication and entertainment
- Appreciate the role of energy transformation in modern life

In groups, learners are guided to:

- Study Figure 3.13 showing applications of energy transformation in daily life
- Discuss applications such as cooking with a gas cooker, charging a phone and driving a car
- Use digital or print media to search for additional applications of energy transformation

How is energy transformation applied to improve our daily lives?

Grade 8 Integrated Science Learner's Book
Charts on energy applications
Internet access
Reference books

Oral questions Written assignments

Force and Energy

Transformation of Energy - Table of energy transformation processes in day-to-day life
Transformation of Energy - Applications: solving problems and extension

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

- Match energy transformation processes to their applications in day-to-day life
- Identify the input and output energy forms in each application
- Show interest in connecting energy transformation to practical technology

- Solve problems identifying energy transformations in given appliances and processes
- Describe the energy transformation chain for specific appliances such as a fan, microphone and generator
- Show confidence in applying knowledge of energy transformation to new situations

In groups, learners are guided to:

- Copy and complete Table 3.3 matching energy transformation processes to applications
- Discuss how the sun is the ultimate source of energy for most processes on Earth
- Solve application-based questions on energy transformations in daily life

- Study the photographs of appliances used in Mahiga Junior School
- Identify energy transformations for each appliance shown
- Discuss why fire extinguishers and safety belts are required in vehicles

How can we trace energy transformation chains in the processes and appliances we use every day?
How can we apply our knowledge of energy transformation to explain the working of various devices?

Grade 8 Integrated Science Learner's Book
Table 3.3
Reference books
Internet access
Grade 8 Integrated Science Learner's Book
Reference books
Internet access

Written assignments Oral questions
Written tests Oral questions

Force and Energy

Transformation of Energy - Project: making a model that demonstrates energy transformation

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

- Design and construct a model that demonstrates at least one energy transformation
- Present the model explaining the energy transformations involved
- Appreciate the creativity and practical skills involved in science projects

In groups, learners are guided to:

- Plan and build a model demonstrating an energy transformation e.g. a wind turbine or a simple electric circuit
- Present the model to classmates and explain the energy transformation chain
- Evaluate models made by other groups and provide feedback

How can we use locally available materials to create a model that demonstrates energy transformation?

Grade 8 Integrated Science Learner's Book
Locally available materials
Internet access

Observation Presentations

Force and Energy

Transformation of Energy - Consolidation and assessment preparation

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

- Review all key concepts in sub-strand 3.1: forms, sources, transformations, safety and applications
- Solve past questions integrating sub-strand 3.1 concepts
- Show confidence in applying energy transformation knowledge

In groups, learners are guided to:

- Complete a comprehensive review of sub-strand 3.1 through group discussion
- Solve structured and application-based questions on energy transformation
- Discuss and correct assessment answers

How well do we understand the concepts of energy transformation?

Grade 8 Integrated Science Learner's Book
Assessment questions
Reference books

Written tests Oral questions

Force and Energy

Transformation of Energy - Consolidation and assessment preparation

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

- Review all key concepts in sub-strand 3.1: forms, sources, transformations, safety and applications
- Solve past questions integrating sub-strand 3.1 concepts
- Show confidence in applying energy transformation knowledge

In groups, learners are guided to:

- Complete a comprehensive review of sub-strand 3.1 through group discussion
- Solve structured and application-based questions on energy transformation
- Discuss and correct assessment answers

How well do we understand the concepts of energy transformation?

Grade 8 Integrated Science Learner's Book
Assessment questions
Reference books

Written tests Oral questions

Force and Energy

Transformation of Energy - Summative assessment
Pressure - Meaning of pressure as used in science

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

- Demonstrate mastery of forms of energy, energy transformations in nature and appliances, safety measures and applications
- Solve application-based questions integrating all sub-strand 3.1 concepts
- Show confidence in applying energy transformation knowledge to real-life situations

- Define pressure as the force acting on a unit area
- State the formula: Pressure = Force ÷ Area
- Show interest in understanding how force and area determine pressure

In groups, learners are guided to:

- Complete a summative written assessment on sub-strand 3.1
- Discuss assessment answers after marking
- Reflect on learning progress across sub-strand 3.1

- Carry out an activity using a pencil or nail on a piece of carton to investigate the effect of area on pressure
- Discuss which two factors pressure depends on from the activity
- Discuss the meaning of pressure from observations

How well have we mastered the concepts in sub-strand 3.1: Transformation of Energy?
What is pressure and what factors does it depend on?

Grade 8 Integrated Science Learner's Book
Assessment papers
Reference books
Grade 8 Integrated Science Learner's Book
Pencil or nail
Piece of carton
Reference books

Written tests Observation
Observation Oral questions

Force and Energy

Pressure - Pressure in solids

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

- Describe pressure in solids as the force exerted per unit area on a surface
- Explain how the area of contact affects the pressure exerted by a solid
- Appreciate that the same force exerts more pressure on a smaller area

In groups, learners are guided to:

- Discuss how a rectangular block exerts different pressures depending on which face rests on the surface
- Study Figure 3.16 showing a block exerting more pressure in position A than position B
- Describe pressure in solids based on observations in Activity 3

How does the area of contact affect the pressure exerted by a solid?

Grade 8 Integrated Science Learner's Book
Rectangular blocks
Sand or soft clay
Reference books

Observation Oral questions Written tests

Force and Energy

Pressure - Pressure in liquids: variation with depth

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

- Describe how pressure in liquids varies with depth
- Explain why pressure in a liquid increases with depth
- Show interest in investigating pressure in liquids experimentally

In groups, learners are guided to:

- Carry out an activity using a bottle with holes at different heights to show how depth affects water pressure
- Observe through which hole water jets land farthest and discuss the relationship between depth and pressure
- Study Figure 3.18 showing water jets from holes at different depths

How does depth affect the pressure in a liquid?

Grade 8 Integrated Science Learner's Book
Plastic bottle
Holes at different heights
Water
Basin

Observation Oral questions

Force and Energy

Pressure - Pressure in liquids: variation with depth

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

- Describe how pressure in liquids varies with depth
- Explain why pressure in a liquid increases with depth
- Show interest in investigating pressure in liquids experimentally

In groups, learners are guided to:

- Carry out an activity using a bottle with holes at different heights to show how depth affects water pressure
- Observe through which hole water jets land farthest and discuss the relationship between depth and pressure
- Study Figure 3.18 showing water jets from holes at different depths

How does depth affect the pressure in a liquid?

Grade 8 Integrated Science Learner's Book
Plastic bottle
Holes at different heights
Water
Basin

Observation Oral questions

Force and Energy

Pressure - Pressure in liquids: effect of density and communicating tubes
Pressure - Pressure in liquids acts in all directions

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

- Describe how the density of a liquid affects the pressure it exerts
- Explain the principle of communicating tubes using the example of water at the same level
- Appreciate the application of pressure in liquids in everyday tools and systems

- Describe that liquid pressure acts equally in all directions at the same depth
- Demonstrate that liquid pressure acts in all directions using a funnel and rubber sheet
- Show interest in using experiments to verify properties of liquid pressure

In groups, learners are guided to:

- Carry out an activity comparing pressure in water and kerosene at the same depth using Figure 3.21
- Study the communicating tubes in Figure 3.20 and discuss why water settles at the same level
- Discuss the application of communicating tubes in plumbing and water level indicators

- Carry out an activity using a funnel with a rubber sheet stretched over its mouth submerged in water
- Observe the rubber sheet bowing equally regardless of the direction the funnel faces
- Study Figure 3.24 showing pressure acting in all directions in a liquid

How does the density of a liquid affect the pressure it exerts at a given depth?
Why does pressure in a liquid act equally in all directions at the same depth?

Grade 8 Integrated Science Learner's Book
Communicating tubes
Water
Kerosene
Funnel
Grade 8 Integrated Science Learner's Book
Funnel
Rubber sheet
Water
Beaker

Observation Oral questions Written assignments

Force and Energy

Pressure - Pressure in liquids: horizontal pressure at the same depth

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

- Describe that liquid pressure at the same depth is equal regardless of horizontal position
- Demonstrate that liquid pressure is equal at the same horizontal level
- Appreciate that the properties of liquid pressure have important practical applications

In groups, learners are guided to:

- Carry out Activity 8 to show that pressure is equal at the same depth in a horizontal direction
- Observe water jets from holes at the same height in Figure 3.23
- Discuss why water from holes at the same depth travels the same horizontal distance

Why is liquid pressure equal at the same depth regardless of horizontal position?

Grade 8 Integrated Science Learner's Book
Plastic bottle with holes at same height
Water
Basin

Observation Written tests

Force and Energy

Pressure - Pressure in liquids: horizontal pressure at the same depth

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

- Describe that liquid pressure at the same depth is equal regardless of horizontal position
- Demonstrate that liquid pressure is equal at the same horizontal level
- Appreciate that the properties of liquid pressure have important practical applications

In groups, learners are guided to:

- Carry out Activity 8 to show that pressure is equal at the same depth in a horizontal direction
- Observe water jets from holes at the same height in Figure 3.23
- Discuss why water from holes at the same depth travels the same horizontal distance

Why is liquid pressure equal at the same depth regardless of horizontal position?

Grade 8 Integrated Science Learner's Book
Plastic bottle with holes at same height
Water
Basin

Observation Written tests

Force and Energy

Pressure - Calculating pressure in solids

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

- Apply the formula Pressure = Force ÷ Area to calculate pressure exerted by solids
- Solve worked examples calculating greatest and least pressure of a rectangular block
- Show interest in applying mathematical skills to solve pressure problems

In groups, learners are guided to:

- Study the worked example: rectangular block 15 cm × 6 cm calculating greatest and least pressure
- Solve practice problems on pressure in solids
- Discuss the units of pressure: pascals (Pa) or N/m²

How do we calculate the pressure exerted by a solid on a surface?

Grade 8 Integrated Science Learner's Book
Worked examples
Reference books
Calculator

Written tests Calculations

Force and Energy

Pressure - Calculating pressure in solids: practice problems
Pressure - Calculating pressure in liquids

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

- Solve problems calculating pressure exerted by rectangular and cylindrical solids
- Convert units of area and force correctly when calculating pressure
- Show confidence in solving pressure calculation problems

- Apply the formula P = hρg to calculate pressure in liquids
- Solve worked examples on pressure in liquids at given depths
- Show interest in applying the pressure formula to liquid problems

In groups, learners are guided to:

- Solve problems in the Checkpoint: rectangular block of concrete 3.6 N and cylindrical block 77 g
- Calculate pressure for a rectangular stone block 32 cm × 25 cm × 20 cm
- Peer-check calculations and discuss common errors

- Study the formula for pressure in liquids: P = hρg where h = depth, ρ = density, g = gravitational field strength
- Solve worked examples calculating pressure at the bottom of a water column
- Solve practice problems on pressure in liquids

How do we apply the pressure formula to solve problems involving solids of different shapes?
How do we calculate the pressure exerted by a liquid at a given depth?

Grade 8 Integrated Science Learner's Book
Calculator
Past exercise books
Reference books
Grade 8 Integrated Science Learner's Book
Worked examples
Calculator
Reference books

Written tests Calculations

Force and Energy

Pressure - Applications of pressure in solids

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

- Describe applications of pressure in solids in day-to-day life
- Explain how knowledge of pressure is applied in the design of tyres, cutting tools and shoulder straps
- Appreciate that understanding pressure helps in designing safer and more efficient tools

In groups, learners are guided to:

- Discuss why trucks that carry heavy loads have many wheels
- Discuss why cutting tools are more efficient when sharp
- Discuss why a backpack has broad shoulder straps as shown in Figure 3.29

How is knowledge of pressure in solids applied in the design of everyday tools and equipment?

Grade 8 Integrated Science Learner's Book
Reference books
Internet access
Charts

Oral questions Written assignments

Force and Energy

Pressure - Applications of pressure in solids

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

- Describe applications of pressure in solids in day-to-day life
- Explain how knowledge of pressure is applied in the design of tyres, cutting tools and shoulder straps
- Appreciate that understanding pressure helps in designing safer and more efficient tools

In groups, learners are guided to:

- Discuss why trucks that carry heavy loads have many wheels
- Discuss why cutting tools are more efficient when sharp
- Discuss why a backpack has broad shoulder straps as shown in Figure 3.29

How is knowledge of pressure in solids applied in the design of everyday tools and equipment?

Grade 8 Integrated Science Learner's Book
Reference books
Internet access
Charts

Oral questions Written assignments

Force and Energy

Pressure - Applications of pressure in liquids: Pascal's principle

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

- State Pascal's principle: pressure applied to an enclosed liquid is transmitted equally in all directions
- Describe how Pascal's principle is applied in hydraulic machines
- Appreciate that Pascal's principle enables small forces to lift heavy loads

In groups, learners are guided to:

- Read the information on Pascal's principle and discuss in groups
- Discuss how hydraulic machines such as the hydraulic press and hydraulic jack use Pascal's principle
- Discuss the hydraulic braking system as an application of liquid pressure

How does Pascal's principle explain the working of hydraulic machines?

Grade 8 Integrated Science Learner's Book
Reference books
Internet access
Charts on hydraulic systems

Oral questions Written tests

Force and Energy

Pressure - Applications: hydraulic press, hydraulic jack and hydraulic braking system
Pressure - Calculating pressure in hydraulic systems

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

- Describe how the hydraulic press and hydraulic jack use Pascal's principle
- Describe the hydraulic braking system and how it slows down a car
- Show interest in understanding how liquid pressure is used in engineering

- Apply Pascal's principle to calculate forces and pressures in hydraulic systems
- Solve worked examples on hydraulic press calculations
- Show confidence in applying Pascal's principle to solve problems

In groups, learners are guided to:

- Study the working of the hydraulic press: pushing plunger down transmits pressure to lift a load
- Discuss the hydraulic jack used to lift vehicles in a garage
- Discuss the hydraulic braking system: pressing brake pedal transmits force to brake pads

- Study the worked example: force of 10 N applied on smaller piston, calculate force on larger piston
- Solve practice problems on hydraulic systems using the relationship P₁ = P₂
- Peer-check solutions and discuss common errors

How do hydraulic machines use Pascal's principle to multiply force?
How do we apply Pascal's principle to calculate forces in hydraulic systems?

Grade 8 Integrated Science Learner's Book
Charts showing hydraulic systems
Internet access
Reference books
Grade 8 Integrated Science Learner's Book
Worked examples
Calculator
Reference books

Oral questions Written assignments
Written tests Calculations

Force and Energy

Pressure - More applications: pressure in solids and liquids

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

- Identify and describe additional applications of pressure in solids and liquids
- Explain how pressure principles are used in dams, syringes and water supply systems
- Appreciate the wide range of engineering applications based on pressure

In groups, learners are guided to:

- Use digital or print media to research applications of pressure in solids and liquids
- Discuss how tall dams hold back large volumes of water using liquid pressure principles
- Discuss how syringes use liquid pressure to administer medicine

What are the other ways in which pressure in solids and liquids is applied in our daily lives?

Grade 8 Integrated Science Learner's Book
Internet access
Reference books
Charts

Oral questions Written assignments

Force and Energy

Pressure - More applications: pressure in solids and liquids

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

- Identify and describe additional applications of pressure in solids and liquids
- Explain how pressure principles are used in dams, syringes and water supply systems
- Appreciate the wide range of engineering applications based on pressure

In groups, learners are guided to:

- Use digital or print media to research applications of pressure in solids and liquids
- Discuss how tall dams hold back large volumes of water using liquid pressure principles
- Discuss how syringes use liquid pressure to administer medicine

What are the other ways in which pressure in solids and liquids is applied in our daily lives?

Grade 8 Integrated Science Learner's Book
Internet access
Reference books
Charts

Oral questions Written assignments

Force and Energy

Pressure - Summative assessment

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

- Demonstrate mastery of pressure in solids and liquids, Pascal's principle, applications and calculations
- Solve structured and application-based questions covering sub-strand 3.2
- Show confidence in applying knowledge of pressure to real-life situations

In groups, learners are guided to:

- Complete a summative written assessment on sub-strand 3.2
- Discuss assessment answers after marking to consolidate understanding
- Reflect on learning progress across sub-strand 3.2

How well have we mastered the concepts in sub-strand 3.2: Pressure?

Grade 8 Integrated Science Learner's Book
Assessment papers
Reference books

Written tests Oral questions