Mixtures, Elements and Compounds

Classes of Fire - Role of oxygen in combustion

By the end of the lesson, the learner should be able to:
- Explain the role of oxygen in combustion
- Describe how the supply of oxygen affects the spread of fire
- Show interest in understanding fire as a chemical reaction

In groups, learners are guided to:
- Carry out an activity using a burning candle and glass container to investigate oxygen's role
- Observe that fire goes out when oxygen enclosed by the container is used up
- Discuss how increased oxygen supply causes fire to spread faster

What role does oxygen play in combustion and the spread of fire?

Active Integrated Science Grade 8 pg. 55
Candle
Transparent glass container
Matchbox

Observation Oral questions

Mixtures, Elements and Compounds

Classes of Fire - Preparation of oxygen in the laboratory
Classes of Fire - Physical and chemical properties of oxygen
Classes of Fire - Causes of fire and classification into classes

By the end of the lesson, the learner should be able to:
- Prepare oxygen in the laboratory using hydrogen peroxide and manganese (IV) oxide
- Describe the over-water collection method for oxygen
- Appreciate the importance of laboratory safety during gas preparation
- Identify and describe the possible causes of fire in nature
- Classify fires according to their causes into Classes A, B, C, D, E and K/F
- Show interest in understanding fire behaviour to promote personal safety

In groups, learners are guided to:
- Set up apparatus and prepare oxygen using hydrogen peroxide with manganese (IV) oxide as catalyst
- Collect oxygen by the over-water method and confirm it using a glowing splint
- Discuss the role of manganese (IV) oxide as a catalyst in the decomposition reaction
- Discuss the possible causes of fire in nature
- Brainstorm on the different classes of fire using a scenario from the county fire department
- Complete Table 1.25 showing classes of fire and their causes

How is oxygen prepared safely in the laboratory and what is the role of a catalyst?
How are fires classified according to their causes?

Active Integrated Science Grade 8 pg. 55
Hydrogen peroxide
Manganese (IV) oxide
Delivery tube
Water trough
Active Integrated Science Grade 8 pg. 57
Boiling tubes of oxygen
Wooden splints
Litmus papers
Active Integrated Science Grade 8 pg. 59
Charts showing fire classes
Internet access
Reference books

Observation Oral questions Written tests

Mixtures, Elements and Compounds

Classes of Fire - Class A, B and C fires

By the end of the lesson, the learner should be able to:
- Describe Class A fires caused by wood, paper, plastics and textiles
- Describe Class B fires caused by flammable liquids: petrol, diesel, kerosene
- Appreciate the importance of knowing the class of fire before attempting to extinguish it

In groups, learners are guided to:
- Discuss causes and examples of Class A, B and C fires using Table 1.26
- Watch digital videos and animations on Class A, B and C fires
- Role-play identifying the class of fire from given scenarios

What distinguishes Class A, B and C fires and how should each be handled?

Active Integrated Science Grade 8 pg. 61
Digital videos on fire classes
Internet access
Charts

Observation Oral questions

Mixtures, Elements and Compounds

Classes of Fire - Class D, E and K/F fires

By the end of the lesson, the learner should be able to:
- Describe Class D fires caused by flammable metals: sodium, lithium, magnesium and potassium
- Describe Class E fires caused by electrical faults and Class K/F fires caused by hot cooking oils
- Show interest in applying knowledge of fire classes to prevent accidents

In groups, learners are guided to:
- Discuss Class D fires citing the example of lithium in mobile phone batteries
- Discuss real-life fire accidents caused by Class D, E and K/F fires
- Present information on assigned fire classes to classmates

What are Class D, E and K/F fires and what makes each of them particularly dangerous?

Active Integrated Science Grade 8 pg. 62
Digital videos
Reference books
Internet access

Observation Oral questions Written assignments

Mixtures, Elements and Compounds

Classes of Fire - The fire triangle and its components
Classes of Fire - How to break the fire triangle
Classes of Fire - Fire control measures

By the end of the lesson, the learner should be able to:
- Identify the three components of the fire triangle: oxygen, fuel and heat
- Explain the role of each component of the fire triangle in sustaining fire
- Appreciate that removing any one component of the fire triangle extinguishes a fire
- Describe ways of breaking each component of the fire triangle
- Match fire control measures to the component of the fire triangle they remove
- Show interest in using scientific understanding of fire to promote safety

In groups, learners are guided to:
- Study a chart of the fire triangle and discuss the role of oxygen, fuel and heat
- Discuss how each component keeps a fire burning
- Draw and label the fire triangle
- Discuss how fire blankets remove oxygen, water removes heat and clearing bushes removes fuel
- Complete Table 1.28 showing fire triangle components and how to remove each
- Apply fire triangle knowledge to suggest control measures for given fire scenarios

What is the fire triangle and how does each component contribute to fire?
How does breaking the fire triangle help us control and extinguish different classes of fire?

Active Integrated Science Grade 8 pg. 62
Charts showing the fire triangle
Reference books
Active Integrated Science Grade 8 pg. 62
Charts showing the fire triangle
Reference books
Fire extinguisher
Charts showing fire control measures

Observation Oral questions Written tests
Oral questions Written assignments

Mixtures, Elements and Compounds

Classes of Fire - Using a fire extinguisher (PASS)

By the end of the lesson, the learner should be able to:
- Describe the correct procedure for using a fire extinguisher using the PASS acronym
- Identify the appropriate fire extinguisher for a given class of fire
- Show interest in practising fire safety and emergency response

In groups, learners are guided to:
- Read and discuss the PASS procedure: Pull pin, Aim at base, Squeeze lever, Sweep side to side
- Practise using a fire extinguisher on a small controlled fire using waste paper or dry grass
- Inspect a fire extinguisher to check its pressure gauge and suitability for a given class of fire

How do we correctly use a fire extinguisher to put out different classes of fire?

Active Integrated Science Grade 8 pg. 62
Fire extinguisher
Waste paper or dry grass
Open area

Observation Oral questions Practical assessment

Mixtures, Elements and Compounds

Classes of Fire - Dangers of accidental fires in nature and the environment

By the end of the lesson, the learner should be able to:
- Describe the dangers of accidental fires including loss of life, property damage and deforestation
- Identify scenarios in which different classes of fire can cause harm
- Acknowledge the dangers of fires and the need for community preparedness

In groups, learners are guided to:
- Discuss the dangers of accidental fires using cases from digital or print media
- Discuss what members of the community can do to prevent fire accidents
- Prepare short notes on fire dangers for a community awareness session

What are the dangers of accidental fires and how can they be prevented?

Active Integrated Science Grade 8 pg. 62
Internet access
Reference books
News articles on fires

Oral questions Observation

Mixtures, Elements and Compounds

Classes of Fire - Right to safety and access to information on flammable substances
Classes of Fire - Role of oxygen in day-to-day life

By the end of the lesson, the learner should be able to:
- Explain the right of consumers to access safety information on flammable substances
- Identify hazard symbols for flammable substances on product labels
- Appreciate the ethical responsibility of manufacturers to warn consumers of fire hazards
- Describe the role of oxygen in day-to-day life: respiration, combustion, hospitals and welding
- Explain how oxygen is used in industrial processes such as welding and cutting metals
- Appreciate the life-sustaining and industrial importance of oxygen

In groups, learners are guided to:
- Study labels on packaging of flammable household items: methylated spirit, air freshener, nail polish remover
- Identify and discuss hazard symbols and safety warnings on flammable products
- Discuss why manufacturers must indicate flammable hazards on product labels
- Discuss the uses of oxygen in hospitals, deep-sea diving, mountain climbing and welding
- Relate the uses of oxygen to its properties: supports combustion and is necessary for respiration
- Prepare short notes on the role of oxygen in day-to-day life

What right do consumers have to safety information on flammable substances?
How does oxygen support life and industrial processes in our daily lives?

Active Integrated Science Grade 8 pg. 67
Packaging of flammable items
Internet access
Active Integrated Science Grade 8 pg. 68
Internet access
Reference books

Observation Oral questions Written assignments

Mixtures, Elements and Compounds

Classes of Fire - Practising fire control measures
Classes of Fire - Community fire awareness

By the end of the lesson, the learner should be able to:
- Demonstrate the correct use of fire control equipment available in the school
- Follow safety procedures when practising fire control measures
- Show interest in participating in fire safety drills and awareness activities

In groups, learners are guided to:
- Collaboratively practise fire control measures using available equipment
- Participate in a fire drill organised by the teacher
- Debrief after the drill to identify areas of improvement

How can we stay safe and protect others during a fire emergency?

Active Integrated Science Grade 8 pg. 62
Fire extinguisher
Fire assembly point
Open area
Active Integrated Science Grade 8 pg. 67
Internet access
Reference books

Practical assessment Observation

Mixtures, Elements and Compounds

Classes of Fire - Integrating fire safety with rights and responsibilities

By the end of the lesson, the learner should be able to:
- Explain the responsibilities of institutions in providing fire safety information and equipment
- Describe the rights of individuals to access fire safety information
- Show interest in advocating for fire safety in their environment

In groups, learners are guided to:
- Discuss responsibilities of schools, hospitals and businesses to provide fire safety equipment
- Identify fire control measures in the school laboratory, kitchen and administration area
- Discuss consequences of failing to comply with fire safety regulations

What responsibilities do institutions have in ensuring fire safety for the people they serve?

Active Integrated Science Grade 8 pg. 67
Internet access
Reference books

Oral questions Written assignments

Mixtures, Elements and Compounds
Mixtures, Elements and Compounds
Living Things and their Environment

Classes of Fire - Strand 1 integration and review
Classes of Fire - Strand 1 summative assessment
The Cell - Components of a cell as seen under the light microscope

By the end of the lesson, the learner should be able to:
- Connect key concepts across Strand 1: elements, physical and chemical changes, and classes of fire
- Solve integrated problems that span the three sub-strands of Strand 1
- Show interest in recognising links between the sub-strands
- Demonstrate mastery of all Strand 1 concepts: elements, physical and chemical changes and classes of fire
- Solve structured and application-based questions covering the full strand
- Show confidence in applying Strand 1 knowledge to real-world situations

In groups, learners are guided to:
- Discuss how elements relate to chemical changes and how combustion underpins fire
- Solve integrated questions covering elements, physical and chemical changes and fire
- Complete a concept map linking Strand 1 topics
- Complete a summative assessment covering all sub-strands of Strand 1
- Discuss assessment answers after marking to consolidate understanding
- Reflect on learning progress across the strand

How are the concepts of elements, physical and chemical changes, and classes of fire connected?
How well have we mastered the concepts in Strand 1: Mixtures, Elements and Compounds?

Active Integrated Science Grade 8 pg. 53
Reference books
Internet access
Active Integrated Science Grade 8 pg. 70
Assessment papers
Reference books
Active Integrated Science Grade 8 pg. 74
Light microscope
Charts of cell structure

Oral questions Written assignments
Written tests Oral questions

Living Things and their Environment

The Cell - Plant cell as observed under a light microscope
The Cell - Functions of components of a plant cell

By the end of the lesson, the learner should be able to:
- Identify and describe components of a plant cell as seen under a light microscope
- Prepare and mount a temporary slide of plant cells
- Show interest in handling laboratory equipment carefully and safely

In groups, learners are guided to:
- Collaboratively prepare and mount a temporary slide of onion epidermal cells
- Observe and draw the plant cell noting the cell wall, cell membrane, nucleus, cytoplasm and vacuole
- Discuss why chloroplasts were not visible in onion epidermal cells

What structures can be seen in a plant cell under a light microscope?

Active Integrated Science Grade 8 pg. 75
Light microscope
Onion
Iodine solution
Slides and coverslips
Charts of plant cell
Internet access
Reference books

Observation Oral questions Drawings

Living Things and their Environment

The Cell - Animal cell as observed under a light microscope
The Cell - Functions of components of animal and plant cells
The Cell - Comparing plant and animal cells as observed under a light microscope

By the end of the lesson, the learner should be able to:
- Identify and describe components of an animal cell as seen under a light microscope
- Observe and draw an animal cell from a permanent slide
- Show interest in making accurate scientific drawings

In groups, learners are guided to:
- Observe a permanent slide of animal cells under the light microscope
- Draw and label one animal cell showing cell membrane, nucleus and cytoplasm
- Discuss the shape of the animal cell as regular or irregular

What structures can be seen in an animal cell under a light microscope?

Active Integrated Science Grade 8 pg. 75
Light microscope
Permanent slide of animal cells
Charts showing cell components
Internet access
Reference books
Charts of plant and animal cells

Observation Oral questions Drawings

Living Things and their Environment

The Cell - Comparing plant and animal cells: size, shape and vacuole
The Cell - Calculating the magnification of a cell as seen under the light microscope
The Cell - Calculating magnification: practice problems

By the end of the lesson, the learner should be able to:
- Compare the size, shape, position of nucleus and presence of vacuole in plant and animal cells
- Classify given diagrams as plant or animal cells based on observed features
- Appreciate the importance of differences between plant and animal cells
- Apply the magnification formula to solve problems at various objective lens settings
- Draw a well-labelled diagram of a cell and indicate the total magnification
- Show confidence in performing calculations related to cell magnification

In groups, learners are guided to:
- Compare the size and shape of plant and animal cells from microscope observations
- Discuss the position of the nucleus and size of the vacuole in each cell type
- Make short notes on similarities between plant and animal cells
- Solve calculation problems on magnification at different objective lens settings
- Fill in the magnification table in Checkpoint 2.1
- Draw and label cell diagrams with correct magnification indicated

What features can be used to distinguish a plant cell from an animal cell?
How does changing the objective lens affect the magnification of a cell?

Active Integrated Science Grade 8 pg. 75
Light microscope
Slides
Charts comparing cells
Active Integrated Science Grade 8 pg. 82
Prepared slides
Reference books
Active Integrated Science Grade 8 pg. 82
Light microscope
Prepared slides
Graph paper

Observation Oral questions Written tests
Written tests Calculations Drawings

Living Things and their Environment

The Cell - Use of a light microscope in magnification
The Cell - Uses of the light microscope in research, medicine and forensic science

By the end of the lesson, the learner should be able to:
- Describe the uses of a light microscope in various fields
- Explain the importance of the light microscope in research, medicine and industry
- Appreciate that the light microscope has transformed our understanding of living things

In groups, learners are guided to:
- Read and dramatise the dialogue involving Dr. William and the Integrated Science teacher
- Discuss four uses of the light microscope in magnification from the dialogue
- Search the internet for additional uses of the light microscope in medicine and crime detection

How is the light microscope useful in day-to-day life and scientific research?

Active Integrated Science Grade 8 pg. 83
Internet access
Reference books
Charts

Oral questions Written assignments

Living Things and their Environment

The Cell - Making charts and models of plant and animal cells

By the end of the lesson, the learner should be able to:
- Draw well-labelled diagrams of a plant and an animal cell on the same chart
- Construct a model of a plant cell using locally available materials
- Appreciate the importance of models and diagrams in communicating scientific ideas

In groups, learners are guided to:
- Make a chart showing plant and animal cells with labels using manila paper
- Construct a model of a plant cell using plasticine of different colours
- Display models in the science corner of the classroom

How can models and charts help us understand the structure of cells?

Active Integrated Science Grade 8 pg. 83
Manila paper
Plasticine of different colours
Markers

Observation Presentations

Living Things and their Environment

The Cell - Importance of cells in living things
The Cell - Safe handling and disposal of materials from cell experiments

By the end of the lesson, the learner should be able to:
- Explain the role of cells as the basic structural and functional unit of life
- Describe how cells work together to form tissues, organs and organ systems
- Appreciate the importance of cells in sustaining life
- Describe safe procedures for handling slides, coverslips and biological specimens
- Explain the importance of disposing of waste from cell experiments appropriately
- Show responsibility in maintaining a clean and safe working environment

In groups, learners are guided to:
- Discuss how cells are the basic unit of all living things
- Use digital or print media to search for information on how cells form tissues and organs
- Discuss examples of how specialised cells perform specific functions
- Discuss safe handling of slides, coverslips and staining materials
- Demonstrate correct disposal of biological waste and broken glass
- Discuss why cleanliness after practical work protects health and the environment

Why are cells considered the basic unit of life?
Why is it important to handle and dispose of materials from experiments safely?

Active Integrated Science Grade 8 pg. 83
Internet access
Reference books
Active Integrated Science Grade 8 pg. 75
Waste disposal containers
Reference books

Oral questions Written assignments
Observation Oral questions

Living Things and their Environment

The Cell - Making a model and chart of plant and animal cells (project)

By the end of the lesson, the learner should be able to:
- Create a poster or model that accurately represents the structure of plant and animal cells
- Present the model or chart to classmates explaining the function of each component
- Appreciate that scientific communication is an important skill

In groups, learners are guided to:
- Collaboratively plan and create a labelled chart showing plant and animal cells
- Construct models of plant and animal cells using available materials
- Display and present models to classmates and discuss component functions

How can we use models to communicate our understanding of cell structure?

Active Integrated Science Grade 8 pg. 75
Manila paper
Plasticine
Markers
Internet access

Observation Presentations

Living Things and their Environment

The Cell - Consolidation and assessment preparation
The Cell - Summative assessment

By the end of the lesson, the learner should be able to:
- Review all key concepts in sub-strand 2.1: cell structure, functions, comparison and magnification
- Solve past questions on cell structure and microscopy
- Show confidence in answering questions on cells and the light microscope

In groups, learners are guided to:
- Complete a review of all sub-strand 2.1 topics through group discussion
- Solve structured and application-based questions on cells and magnification
- Correct and discuss assessment answers

How well do we understand the structure and functions of plant and animal cells?

Active Integrated Science Grade 8 pg. 86
Assessment questions
Reference books
Assessment papers

Written tests Oral questions

Living Things and their Environment

Movement of Materials In and Out of the Cell - Structure of the cell membrane
Movement of Materials In and Out of the Cell - Properties of the cell membrane

By the end of the lesson, the learner should be able to:
- Describe the structure of the cell membrane
- Identify the parts that form the cell membrane including phospholipids and protein molecules
- Show interest in understanding how cell membrane structure enables its functions
- Describe the properties of the cell membrane: semi-permeability, electric charges and sensitivity to temperature and pH
- Explain what semi-permeability means in relation to the cell membrane
- Appreciate that the properties of the cell membrane are essential for cell function

In groups, learners are guided to:
- Study a chart showing the structure of the cell membrane
- Identify the different parts of the cell membrane from Figure 2.15
- Draw and label the parts of the cell membrane
- Study a chart showing how particles move across the cell membrane
- Discuss the role of protein molecules in the properties of the cell membrane
- Discuss how the properties of the cell membrane help it perform its functions

What is the structure of the cell membrane and how does it enable its functions?
Why is it important for the cell membrane to control what gets in and out of the cell?

Active Integrated Science Grade 8 pg. 87
Charts showing cell membrane structure
Internet access
Active Integrated Science Grade 8 pg. 88
Charts showing cell membrane structure
Reference books

Observation Oral questions Drawings
Oral questions Written assignments

Living Things and their Environment

Movement of Materials In and Out of the Cell - Demonstrating semi-permeability of the cell membrane
Movement of Materials In and Out of the Cell - Effects of heat and pH on the cell membrane

By the end of the lesson, the learner should be able to:
- Demonstrate that the cell membrane is semi-permeable
- Explain which particles pass through the cell membrane and which do not
- Show interest in using experiments to verify properties of the cell membrane
- Describe the effect of heat on the functioning of the cell membrane
- Describe the effect of pH change on the functioning of the cell membrane
- Show interest in investigating how environmental factors affect cell membrane function

In groups, learners are guided to:
- Carry out an activity to demonstrate semi-permeability of the cell membrane using a chart
- Study Figure 2.16 showing demonstration of semi-permeability
- Explain the meaning of semi-permeability from the activity
- Carry out an experiment to demonstrate the effect of heat on the cell membrane using beetroot cylinders
- Carry out an experiment to demonstrate the effect of dilute acid and alkali on the cell membrane
- Discuss and record observations on how heat and pH affect membrane functioning

How does semi-permeability of the cell membrane control movement of materials?
How do heat and pH affect the functioning of the cell membrane?

Active Integrated Science Grade 8 pg. 89
Charts showing semi-permeability
Reference books
Active Integrated Science Grade 8 pg. 90
Beetroot cylinders
Test tubes
Dilute acid and alkali
Water bath

Observation Oral questions
Observation Written tests

Living Things and their Environment

Movement of Materials In and Out of the Cell - Demonstrating diffusion
Movement of Materials In and Out of the Cell - Role of diffusion in plants and animals

By the end of the lesson, the learner should be able to:
- Define diffusion as the movement of particles from a region of high concentration to low concentration
- Demonstrate diffusion using a simple experiment
- Show interest in observing diffusion as evidence of particle movement

In groups, learners are guided to:
- Carry out an activity to demonstrate diffusion using potassium manganate (VII) in water
- Observe and record how particles spread out over time
- Discuss the definition of diffusion from the experimental observation

What is diffusion and how can it be demonstrated?

Active Integrated Science Grade 8 pg. 97
Potassium manganate (VII)
Water
Beakers
Reference books
Internet access

Observation Oral questions

Living Things and their Environment

Movement of Materials In and Out of the Cell - Factors affecting the rate of diffusion: temperature and surface area

By the end of the lesson, the learner should be able to:
- Describe how temperature affects the rate of diffusion
- Explain how the ratio of surface area to volume affects the rate of diffusion
- Show interest in investigating factors that affect diffusion

In groups, learners are guided to:
- Carry out an experiment to observe diffusion of ink at different temperatures
- Carry out an activity to find out how surface area to volume ratio affects diffusion
- Discuss and record how increasing temperature increases the rate of diffusion

How do temperature and surface area affect the rate of diffusion?

Active Integrated Science Grade 8 pg. 97
Ink
Hot and cold water
Beakers
Agar cubes

Observation Written tests

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
- Explain how the physical state of particles affects the rate of diffusion
- Describe that gases diffuse faster than liquids, which diffuse faster than solids
- Show interest in relating particle arrangement to 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
- Study Figure 2.26 showing diffusion in different physical states
- Discuss why gaseous particles diffuse fastest based on particle spacing
- Summarise all factors affecting diffusion in a table

How do membrane thickness, particle size and concentration gradient affect diffusion?
Why do substances in different physical states diffuse at different rates?

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

Oral questions Written assignments
Oral questions Written tests

Living Things and their Environment

Movement of Materials In and Out of the Cell - Demonstrating osmosis using potato cylinders

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

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

How does osmosis cause changes in the length of potato cylinders in different solutions?

Active Integrated Science Grade 8 pg. 101
Potato
Distilled water
Sugar solution
Beakers
Ruler

Observation Oral questions Written tests

Living Things and their Environment

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

By the end of the lesson, the learner should be able to:
- Define hypertonic, hypotonic and isotonic solutions
- Predict the direction of water movement when a cell is placed in each type of solution
- Appreciate that solution concentration determines the direction of osmosis

In groups, learners are guided to:
- Study the definitions of hypertonic, hypotonic and isotonic solutions
- Discuss the effect of placing a cell in each type of solution
- Complete questions predicting osmosis outcomes in given scenarios

How does the concentration of the surrounding solution affect osmosis in cells?

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

Oral questions Written assignments

Living Things and their Environment

Movement of Materials In and Out of the Cell - Factors affecting the rate of osmosis
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 factors that affect the rate of osmosis: temperature, concentration gradient, surface area to volume ratio, pressure and membrane thickness
- Explain how each factor influences the rate of osmosis
- Show interest in applying knowledge of osmosis to living systems
- 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:
- Use reading material provided to find out how each factor affects osmosis
- Discuss how increasing temperature, concentration gradient and surface area increase the rate of osmosis
- Summarise factors affecting osmosis in a table
- 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

What factors determine how fast osmosis occurs across a cell membrane?
How does osmosis support the life processes of plants?

Active Integrated Science Grade 8 pg. 103
Reference books
Internet access
Active Integrated Science Grade 8 pg. 105
Reference books
Internet access
Charts

Oral questions Written tests
Oral questions Written assignments

Living Things and their Environment

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

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

Oral questions Written tests

Living Things and their Environment

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:
- Summarise the roles of diffusion and osmosis in living things on a poster
- Present findings on the importance of diffusion and osmosis to classmates
- Appreciate that scientific communication through posters develops presentation skills

In groups, learners are guided to:
- Write roles of diffusion on one manila paper and roles of osmosis on another
- Display posters in the science corner of the classroom
- Discuss the content of posters and compare with classmates

How can a poster help communicate the importance of diffusion and osmosis in living things?

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

Observation Presentations

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
Movement of Materials In and Out of the Cell - Comparing diffusion and osmosis

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

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
- 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

What happens to plant and animal cells when placed in solutions of different concentrations?
How are diffusion and osmosis similar and how do they differ?

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
Active Integrated Science Grade 8 pg. 112
Reference books
Charts comparing diffusion and osmosis

Oral questions Written assignments
Written assignments Oral questions

Living Things and their Environment

Movement of Materials In and Out of the Cell - Summative assessment

By the end of the lesson, the learner should be able to:
- 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:
- 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 well have we mastered the concepts in sub-strand 2.2: Movement of Materials?

Active Integrated Science Grade 8 pg. 112
Assessment papers
Reference books

Written tests Observation