Living Things and their Environment

Movement of Materials In and Out of the Cell - Factors affecting diffusion: membrane thickness, particle size and concentration gradient
Movement of Materials In and Out of the Cell - Effect of physical state on rate of diffusion

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

- Describe how membrane thickness affects the rate of diffusion
- Explain how particle size and concentration gradient affect the rate of diffusion
- Appreciate that multiple factors interact to determine the rate of diffusion

In groups, learners are guided to:

- Study diagrams comparing diffusion through thin and thick membranes
- Study Figure 2.25 showing set-ups with different concentration gradients
- Discuss how increasing concentration gradient increases the rate of diffusion

How do membrane thickness, particle size and concentration gradient affect diffusion?

Active Integrated Science Grade 8 pg. 99
Charts showing concentration gradient
Reference books
Active Integrated Science Grade 8 pg. 100
Charts and diagrams

Oral questions Written assignments

Living Things and their Environment

Movement of Materials In and Out of the Cell - Demonstrating osmosis using potato cylinders
Movement of Materials In and Out of the Cell - Hypertonic, hypotonic and isotonic solutions
Movement of Materials In and Out of the Cell - Demonstrating osmosis using visking tubing
Movement of Materials In and Out of the Cell - Factors affecting the rate of osmosis

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

- Define osmosis as the movement of water molecules across a semi-permeable membrane from a dilute to a concentrated solution
- Demonstrate osmosis using potato cylinders in distilled water and sugar solution
- Show interest in carrying out experiments to investigate osmosis

- Demonstrate osmosis using visking tubing as a model of a semi-permeable membrane
- Explain observations in the visking tubing experiment in terms of osmosis
- Show interest in using models to investigate biological processes

In groups, learners are guided to:

- Set up the experiment: place potato cylinders in distilled water (beaker A) and sugar solution (beaker B)
- Measure and record the length of potato cylinders before and after as in Table 2.3
- Discuss and explain changes in length based on osmosis

- Set up visking tubing experiment: fill with sugar solution, place in distilled water
- Observe results after 30 minutes and compare with Figure 2.27
- Discuss and explain changes in the visking tubing experiment

How does osmosis cause changes in the length of potato cylinders in different solutions?
How does the visking tubing experiment demonstrate the process of osmosis?

Active Integrated Science Grade 8 pg. 101
Potato
Distilled water
Sugar solution
Beakers
Ruler
Active Integrated Science Grade 8 pg. 102
Reference books
Charts showing solution types
Active Integrated Science Grade 8 pg. 103
Visking tubing
Sugar solution
Distilled water
Beaker
Reference books
Internet access

Observation Oral questions Written tests

Living Things and their Environment

Movement of Materials In and Out of the Cell - Role of osmosis in plants

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

- Describe the role of osmosis in opening and closing of stomata in plants
- Explain how osmosis enables feeding in insectivorous plants and supports herbaceous plants
- Appreciate that osmosis is essential for plant survival

In groups, learners are guided to:

- Read about and discuss the role of osmosis in opening and closing of stomata
- Discuss how insectivorous plants trap insects using osmosis-driven leaf movements
- Discuss how osmosis creates turgidity that supports herbaceous plants

How does osmosis support the life processes of plants?

Active Integrated Science Grade 8 pg. 105
Reference books
Internet access
Charts

Oral questions Written assignments

Living Things and their Environment

Movement of Materials In and Out of the Cell - Role of osmosis in animals
Movement of Materials In and Out of the Cell - Poster on importance of diffusion and osmosis

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

- Describe the role of osmosis in absorption of water in the digestive system
- Explain how osmosis enables reabsorption of water in the kidney
- Appreciate the essential role of osmosis in maintaining water balance in animals

In groups, learners are guided to:

- Discuss how water is absorbed from the digestive system into the bloodstream through osmosis
- Discuss how the kidney reabsorbs water into the bloodstream by osmosis
- Research additional roles of osmosis in animals using digital or print media

How does osmosis maintain water balance in animals?

Active Integrated Science Grade 8 pg. 106
Reference books
Internet access
Active Integrated Science Grade 8 pg. 107
Manila paper
Markers

Oral questions Written tests

Living Things and their Environment

Movement of Materials In and Out of the Cell - Turgidity, plasmolysis and crenation
Movement of Materials In and Out of the Cell - Effects of osmosis on plant and animal cells

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

- Describe what happens to plant cells placed in hypotonic and hypertonic solutions
- Define turgidity and plasmolysis in plant cells and crenation and haemolysis in animal cells
- Show interest in explaining the effects of osmosis on cells

In groups, learners are guided to:

- Discuss observations of plant leaves drooping on a sunny day due to loss of water through osmosis
- Study Figures 2.34 and 2.35 showing plasmolysis and turgidity in plant cells
- Study Figures 2.36 and 2.37 showing crenation and haemolysis in red blood cells

What happens to plant and animal cells when placed in solutions of different concentrations?

Active Integrated Science Grade 8 pg. 108
Charts showing turgidity and plasmolysis
Reference books
Active Integrated Science Grade 8 pg. 109
Charts showing cell osmosis effects

Oral questions Written assignments

Living Things and their Environment

Movement of Materials In and Out of the Cell - Comparing diffusion and osmosis
Movement of Materials In and Out of the Cell - Summative assessment
Reproduction in Human Beings - The menstrual cycle in human beings

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

- Identify similarities between diffusion and osmosis
- Identify differences between diffusion and osmosis
- Show interest in using comparison as a scientific thinking skill

- Demonstrate mastery of cell membrane structure and properties, diffusion, osmosis and their roles in living things
- Solve application-based questions integrating all sub-strand 2.2 concepts
- Show confidence in applying knowledge of cell transport to real-life situations

In groups, learners are guided to:

- Discuss similarities: both involve particle movement from high to low concentration
- Discuss differences: osmosis involves water only through a semi-permeable membrane
- Complete Table 2.4 showing incidences that involve diffusion and osmosis

- Complete a summative written assessment on sub-strand 2.2
- Discuss assessment answers after marking to consolidate understanding
- Reflect on learning progress across sub-strand 2.2

How are diffusion and osmosis similar and how do they differ?
How well have we mastered the concepts in sub-strand 2.2: Movement of Materials?

Active Integrated Science Grade 8 pg. 112
Reference books
Charts comparing diffusion and osmosis
Active Integrated Science Grade 8 pg. 112
Assessment papers
Reference books
Internet access
Charts showing menstrual cycle
Digital devices

Written assignments Oral questions
Written tests Observation

Living Things and their Environment

Reproduction in Human Beings - Challenges related to the menstrual cycle
Reproduction in Human Beings - Managing challenges related to the menstrual cycle

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

- Identify challenges related to the menstrual cycle including irregular periods, irregular bleeding and pain
- Describe how each challenge affects daily life
- Show empathy and support towards those experiencing menstrual challenges

In groups, learners are guided to:

- Search for information from print or non-print media on challenges related to the menstrual cycle
- Discuss challenges such as irregular periods, heavy bleeding and menstrual pain
- Share findings in groups and discuss the impact of menstrual challenges on daily activities

What are the common challenges related to the menstrual cycle and how do they affect daily life?

Internet access
Digital devices
Print media

Oral questions Written assignments

Living Things and their Environment

Reproduction in Human Beings - Process of fertilisation in human beings
Reproduction in Human Beings - Process of implantation in human beings

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

- Describe the process of fertilisation as the fusion of a sperm cell with an egg cell
- Explain where fertilisation takes place in the female reproductive system
- Show interest in understanding human reproduction

In groups, learners are guided to:

- Study illustrations and charts on the process of fertilisation
- Discuss the journey of the sperm from the vagina to the fallopian tube
- Discuss the fusion of the sperm and ovum to form a zygote

What is fertilisation and where does it occur in the human body?

Internet access
Charts showing fertilisation
Illustrations
Charts showing implantation

Oral questions Written tests

Living Things and their Environment

Reproduction in Human Beings - Symptoms and prevention of HIV and AIDS

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

- Outline the symptoms of HIV and AIDS in human beings
- Describe prevention measures for HIV and AIDS
- Appreciate the need for a healthy reproductive system

In groups, learners are guided to:

- Search for information from print and non-print materials on symptoms of HIV and AIDS
- Discuss the symptoms of HIV and AIDS and how the disease progresses
- Discuss prevention measures including abstinence, faithful partnership and condom use

What are the symptoms of HIV and AIDS and how can infection be prevented?

Internet access
Charts on HIV and AIDS
Digital devices

Oral questions Written assignments

Living Things and their Environment

Reproduction in Human Beings - Symptoms and prevention of gonorrhoea and syphilis
Reproduction in Human Beings - Symptoms and prevention of herpes
Reproduction in Human Beings - Prevention measures for common STIs
Reproduction in Human Beings - Importance of a healthy reproductive system

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

- Outline the symptoms of gonorrhoea and syphilis in human beings
- Describe prevention measures for gonorrhoea and syphilis
- Show respect and open-mindedness when discussing STIs

- Compare prevention measures across common STIs: HIV and AIDS, gonorrhoea, syphilis and herpes
- Develop a community awareness message on STI prevention
- Show responsibility in promoting reproductive health

In groups, learners are guided to:

- Search for information on symptoms of gonorrhoea and syphilis from print and non-print materials
- Discuss the symptoms of each STI and how they differ
- Discuss prevention measures for gonorrhoea and syphilis

- Discuss and compare prevention measures for all STIs studied
- Role-play peer conversations about STI prevention
- Prepare a short community awareness message on STI prevention

What are the symptoms of gonorrhoea and syphilis and how can they be prevented?
How can knowledge of STI prevention help protect individuals and the community?

Internet access
Charts on gonorrhoea and syphilis
Digital devices
Print media
Internet access
Charts on STI prevention
Digital devices
Print media

Oral questions Written tests
Oral questions Presentations

Living Things and their Environment
Force and Energy

Reproduction in Human Beings - Summative assessment
Transformation of Energy - Forms of energy in nature

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

- Demonstrate mastery of the menstrual cycle, fertilisation, implantation and STIs
- Solve structured and application-based questions covering sub-strand 2.3
- Show confidence in applying knowledge of reproduction to real-life situations

In groups, learners are guided to:

- Complete a summative written assessment on sub-strand 2.3
- Discuss assessment answers after marking to consolidate understanding
- Reflect on learning progress across sub-strand 2.3

How well have we mastered the concepts in sub-strand 2.3: Reproduction in Human Beings?

Assessment questions
Internet access
Digital devices
Active Integrated Science Grade 8 pg. 115
Charts showing forms of energy
Reference books

Written tests Oral questions

Force and Energy

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
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:

- Classify energy sources in nature into renewable and non-renewable sources
- Give examples of renewable sources such as solar, wind, geothermal and hydroelectric
- Appreciate the importance of using renewable energy sources

In groups, learners are guided to:

- Discuss and classify energy sources from Table 3.1 into renewable and non-renewable
- Use digital or print media to search for information on classification of energy sources
- Discuss the advantages of renewable over non-renewable energy sources

What is the difference between renewable and non-renewable energy sources?

Active Integrated Science Grade 8 pg. 116
Table 3.1 energy sources chart
Internet access
Reference books
Active Integrated Science Grade 8 pg. 117
Active Integrated Science Grade 8 pg. 118
Pendulum or swinging equipment
Active Integrated Science Grade 8 pg. 119
Cardboard
Wire
Charts showing turbine

Oral questions Written assignments

Force and Energy

Transformation of Energy - Making a turbine model
Transformation of Energy - Appliances that rely on energy transformation
Transformation of Energy - Energy transformations in specific appliances

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?

Active Integrated Science Grade 8 pg. 120
Cardboard strips
Wire
Plastic strip
Water
Active Integrated Science Grade 8 pg. 123
Charts showing appliances
Actual appliances
Reference books
Active Integrated Science Grade 8 pg. 124
Internet access
Table 3.2

Observation Presentations

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
Transformation of Energy - Safety measures: research and presentation
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 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

- 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:

- 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

- 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

What safety measures should we observe to prevent accidents related to energy transformation?
How can we use knowledge of energy transformation to promote safety in our community?

Active Integrated Science Grade 8 pg. 124
Internet access
Reference books
Charts
Active Integrated Science Grade 8 pg. 125
Active Integrated Science Grade 8 pg. 126
Internet access
Reference books
Active Integrated Science Grade 8 pg. 127
Charts on energy applications

Oral questions Written assignments
Presentations Oral questions

Force and Energy

Transformation of Energy - Table of energy transformation processes in day-to-day life

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

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

How can we trace energy transformation chains in the processes and appliances we use every day?

Active Integrated Science Grade 8 pg. 128
Table 3.3
Reference books
Internet access

Written assignments Oral questions

Force and Energy

Transformation of Energy - Applications: solving problems and extension
Transformation of Energy - Project: making a model that demonstrates energy transformation

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

- 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:

- 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 apply our knowledge of energy transformation to explain the working of various devices?

Active Integrated Science Grade 8 pg. 129
Reference books
Internet access
Active Integrated Science Grade 8 pg. 127
Locally available materials

Written tests Oral questions

Force and Energy

Transformation of Energy - Consolidation and assessment preparation
Transformation of Energy - Summative assessment

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?

Active Integrated Science Grade 8 pg. 128
Assessment questions
Reference books
Active Integrated Science Grade 8 pg. 129
Assessment papers

Written tests Oral questions

Force and Energy

Pressure - Meaning of pressure as used in science
Pressure - Pressure in solids
Pressure - Pressure in liquids: variation with depth

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

- 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

- 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 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

- 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

What is pressure and what factors does it depend on?
How does depth affect the pressure in a liquid?

Active Integrated Science Grade 8 pg. 130
Pencil or nail
Piece of carton
Reference books
Active Integrated Science Grade 8 pg. 131
Rectangular blocks
Sand or soft clay
Active Integrated Science Grade 8 pg. 133
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

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

How does the density of a liquid affect the pressure it exerts at a given depth?

Active Integrated Science Grade 8 pg. 134
Communicating tubes
Water
Kerosene
Funnel
Active Integrated Science Grade 8 pg. 135
Rubber sheet
Beaker

Observation Oral questions Written assignments

Force and Energy

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

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?

Active Integrated Science Grade 8 pg. 137
Plastic bottle with holes at same height
Water
Basin
Active Integrated Science Grade 8 pg. 138
Worked examples
Reference books
Calculator

Observation Written tests

Force and Energy

Pressure - Calculating pressure in solids: practice problems

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

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

How do we apply the pressure formula to solve problems involving solids of different shapes?

Active Integrated Science Grade 8 pg. 139
Calculator
Past exercise books
Reference books

Written tests Calculations

Force and Energy

Pressure - Calculating pressure in liquids
Pressure - Applications of pressure in solids
Pressure - Applications of pressure in liquids: Pascal's principle
Pressure - Applications: hydraulic press, hydraulic jack and hydraulic braking system

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

- 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

- 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:

- 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

- 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 do we calculate the pressure exerted by a liquid at a given depth?
How does Pascal's principle explain the working of hydraulic machines?

Active Integrated Science Grade 8 pg. 140
Worked examples
Calculator
Reference books
Active Integrated Science Grade 8 pg. 142
Internet access
Charts
Active Integrated Science Grade 8 pg. 143
Reference books
Internet access
Charts on hydraulic systems
Active Integrated Science Grade 8 pg. 144
Charts showing hydraulic systems

Written tests Calculations
Oral questions Written tests

Force and Energy

Pressure - Calculating pressure in hydraulic systems
Pressure - More applications: pressure in solids and liquids

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

- 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 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 we apply Pascal's principle to calculate forces in hydraulic systems?

Active Integrated Science Grade 8 pg. 145
Worked examples
Calculator
Reference books
Active Integrated Science Grade 8 pg. 146
Internet access
Charts

Written tests Calculations

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?

Active Integrated Science Grade 8 pg. 146
Assessment papers
Reference books

Written tests Oral questions