Mixtures, Elements and Compounds

Structure of the atom - Protons, electrons and neutrons

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

- Define the term atom
- Describe the structure of an atom including the positions of protons, neutrons and electrons
- Show interest in learning about atoms and their subatomic particles

In groups, learners are guided to:

- Discuss the meaning of an atom and illustrate its structure
- Search the Internet or use reference books to get information about the structure of an atom
- Draw the structure of an atom showing positions and charges of subatomic particles

How is the structure of the atom important?

- Comprehensive Integrated Science Grade 9 pg. 1
- Internet access
- Reference books
- Charts showing atomic structure

- Observation - Oral questions

Mixtures, Elements and Compounds

Structure of the atom - Protons, electrons and neutrons

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

- Identify the subatomic particles in an atom
- Explain the location and electrical charges of subatomic particles
- Show interest in the study of atoms and their electrical charges

In groups, learners are guided to:

- Discuss the composition of an atom
- Demonstrate presence of charges in an atom by rubbing a plastic ruler on dry hair and observing attraction of paper pieces
- Discuss the electrical charges of protons, electrons and neutrons

How small are atoms and are they divisible?

- Comprehensive Integrated Science Grade 9 pg. 1
- Two plastic rulers, thread, retort stand
- Small pieces of paper, glass rod

- Observation - Written tests

Mixtures, Elements and Compounds

Structure of the atom - Atomic number and mass number

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

- Define the terms atomic number and mass number
- Illustrate atomic number and mass number using chemical symbols
- Show appreciation for the uniqueness of each element's atomic number

In groups, learners are guided to:

- Search the Internet or use reference books to find out about atomic number and mass number
- Discuss how atomic number and mass number are represented using chemical symbols
- Calculate and record the mass numbers of given elements

What is the relationship between atomic number and the identity of an element?

- Comprehensive Integrated Science Grade 9 pg. 4
- Internet access
- Reference books
- Periodic table

- Written assignments - Oral questions

Mixtures, Elements and Compounds

Structure of the atom - Atomic number and mass number

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

- Calculate the number of protons, electrons and neutrons given atomic number and mass number
- Determine the mass number of elements using a table of elements
- Appreciate the use of mathematical calculation in science

In groups, learners are guided to:

- Work out the number of protons, electrons and neutrons from given atomic number and mass number
- Fill in a table of elements showing atomic number, number of neutrons and mass number
- Share findings with classmates

How do protons, neutrons and electrons relate to the mass number of an element?

- Comprehensive Integrated Science Grade 9 pg. 4
- Reference books
- Exercise books, pen

- Written assignments - Observation

Mixtures, Elements and Compounds

Structure of the atom - Atomic number and mass number
Structure of the atom - Electron arrangement of elements

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

- Calculate the number of protons, electrons and neutrons given atomic number and mass number
- Determine the mass number of elements using a table of elements
- Appreciate the use of mathematical calculation in science

- Describe how electrons are arranged in energy levels (shells)
- State the maximum number of electrons each energy level can hold
- Show interest in finding out how electrons occupy energy levels

In groups, learners are guided to:

- Work out the number of protons, electrons and neutrons from given atomic number and mass number
- Fill in a table of elements showing atomic number, number of neutrons and mass number
- Share findings with classmates

- Discuss how electrons are distributed across energy levels in atoms
- Study the maximum number of electrons that can occupy each energy level (first: 2; second: 8; third: 8)
- Use digital or print media to search for more information on electron arrangement

How do protons, neutrons and electrons relate to the mass number of an element?
Why do electrons occupy specific energy levels in an atom?

- Comprehensive Integrated Science Grade 9 pg. 4
- Reference books
- Exercise books, pen

- Comprehensive Integrated Science Grade 9 pg. 8
- Internet access
- Reference books
- Charts showing electron energy levels

- Written assignments - Observation

Mixtures, Elements and Compounds

Structure of the atom - Electron arrangement of elements

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

- Write the electron arrangement of elements with atomic numbers 1 to 20
- Fill in a table showing electron distribution across energy levels
- Collaborate effectively in group activities on electron arrangement

In groups, learners are guided to:

- Copy and complete a table showing number of electrons on each energy level for the first 20 elements
- Discuss and verify the electron arrangements collaboratively
- Share and compare findings with classmates

How does the number of electrons in an atom determine its electron arrangement?

- Comprehensive Integrated Science Grade 9 pg. 8
- Exercise books
- Reference books

- Written assignments - Oral questions

Mixtures, Elements and Compounds

Structure of the atom - Energy level diagrams

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

- Explain what energy level diagrams are
- Draw energy level diagrams for simple elements (hydrogen, helium) using dot or cross notation
- Appreciate the use of diagrams to represent atomic structure

In groups, learners are guided to:

- Discuss the meaning of energy level diagrams and how dots or crosses represent electrons
- Draw energy level diagrams for hydrogen and helium atoms step by step
- Present drawings to classmates for comparison

How does an energy level diagram represent the arrangement of electrons in an atom?

- Comprehensive Integrated Science Grade 9 pg. 12
- Exercise books, pencil
- Charts of energy level diagrams

- Observation - Oral questions

Mixtures, Elements and Compounds

Structure of the atom - Energy level diagrams

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

- Draw energy level diagrams for elements with atomic numbers 1 to 20 using dot or cross notation
- Follow the correct steps for drawing energy level diagrams
- Show interest in accurately representing atomic structures

In groups, learners are guided to:

- Follow the step-by-step procedure to draw energy level diagrams (e.g. chlorine: identify number of electrons, draw nucleus, add first, second and third energy levels)
- Draw energy level diagrams for various elements in pairs
- Share and discuss diagrams with classmates

What information can be obtained from an energy level diagram?

- Comprehensive Integrated Science Grade 9 pg. 12
- Exercise books, pencil
- Reference books

- Written assignments - Observation

Mixtures, Elements and Compounds

Structure of the atom - Energy level diagrams
Structure of the atom - Classifying elements into metals and non-metals

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

- Draw energy level diagrams for a range of elements from the first 20 in the periodic table
- Identify and correct errors in drawn energy level diagrams
- Demonstrate diligence in constructing accurate energy level diagrams

- Explain how electron arrangement is used to classify elements into metals and non-metals
- Use electron arrangement to distinguish between metals and non-metals
- Show interest in using electron arrangement to classify elements

In groups, learners are guided to:

- Identify the number of electrons for various elements from a table
- Draw energy level diagrams for the listed elements using dots or crosses
- Pair up dots or crosses in each energy level to ease counting
- Share and verify diagrams with classmates

- Search for information on how electron arrangement differentiates metals from non-metals
- Discuss findings and write short notes in exercise books
- Present findings to classmates

How does the number of energy levels relate to the period of an element?
How does electron arrangement help in classifying elements as metals or non-metals?

- Comprehensive Integrated Science Grade 9 pg. 12
- Exercise books, pencil
- Reference books

- Comprehensive Integrated Science Grade 9 pg. 16
- Internet access
- Reference books

- Written assignments - Oral questions

Mixtures, Elements and Compounds

Structure of the atom - Classifying elements into metals and non-metals

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

- Explain how electron arrangement is used to classify elements into metals and non-metals
- Use electron arrangement to distinguish between metals and non-metals
- Show interest in using electron arrangement to classify elements

In groups, learners are guided to:

- Search for information on how electron arrangement differentiates metals from non-metals
- Discuss findings and write short notes in exercise books
- Present findings to classmates

How does electron arrangement help in classifying elements as metals or non-metals?

- Comprehensive Integrated Science Grade 9 pg. 16
- Internet access
- Reference books

- Oral questions - Observation

Mixtures, Elements and Compounds

Structure of the atom - Classifying elements into metals and non-metals

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

- Explain how electron arrangement is used to classify elements into metals and non-metals
- Use electron arrangement to distinguish between metals and non-metals
- Show interest in using electron arrangement to classify elements

In groups, learners are guided to:

- Search for information on how electron arrangement differentiates metals from non-metals
- Discuss findings and write short notes in exercise books
- Present findings to classmates

How does electron arrangement help in classifying elements as metals or non-metals?

- Comprehensive Integrated Science Grade 9 pg. 16
- Internet access
- Reference books

- Oral questions - Observation

Mixtures, Elements and Compounds

Structure of the atom - Classifying elements into metals and non-metals

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

- Complete a table showing electron arrangement of given elements
- Classify elements as metals or non-metals based on their electron arrangement
- Appreciate the importance of electron arrangement in understanding element properties

In groups, learners are guided to:

- Copy and complete a table showing the number of electrons and electron arrangement of elements (beryllium, helium, sodium, carbon, potassium, fluorine, phosphorus)
- Classify the listed elements as metals or non-metals
- Present and explain the completed table to classmates

Which elements are metals and which are non-metals based on their electron arrangement?

- Comprehensive Integrated Science Grade 9 pg. 16
- Manila paper
- Reference books

- Written assignments - Observation
-

Mixtures, Elements and Compounds

Structure of the atom - Classifying elements into metals and non-metals

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

- Complete a table showing electron arrangement of given elements
- Classify elements as metals or non-metals based on their electron arrangement
- Appreciate the importance of electron arrangement in understanding element properties

- Identify metals and non-metals from given energy level diagrams
- Give reasons for classifying elements as metals or non-metals
- Collaborate with peers in classifying elements

In groups, learners are guided to:

- Copy and complete a table showing the number of electrons and electron arrangement of elements (beryllium, helium, sodium, carbon, potassium, fluorine, phosphorus)
- Classify the listed elements as metals or non-metals
- Present and explain the completed table to classmates

- Study energy level diagrams of various elements
- Identify and classify elements as metals or non-metals from their energy level diagrams
- Give reasons to support each classification
- Share classifications with the class

Which elements are metals and which are non-metals based on their electron arrangement?
Why are some elements with similar electron arrangements still different in properties?

- Comprehensive Integrated Science Grade 9 pg. 16
- Manila paper
- Reference books

- Comprehensive Integrated Science Grade 9 pg. 16
- Charts showing energy level diagrams
- Exercise books

- Written assignments - Observation
-

Mixtures, Elements and Compounds

Structure of the atom - Classifying elements into metals and non-metals

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

- Identify metals and non-metals from given energy level diagrams
- Give reasons for classifying elements as metals or non-metals
- Collaborate with peers in classifying elements

In groups, learners are guided to:

- Study energy level diagrams of various elements
- Identify and classify elements as metals or non-metals from their energy level diagrams
- Give reasons to support each classification
- Share classifications with the class

Why are some elements with similar electron arrangements still different in properties?

- Comprehensive Integrated Science Grade 9 pg. 16
- Charts showing energy level diagrams
- Exercise books

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Structure of the atom - Atomic structure models

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

- Plan and design a model of atomic structure for a chosen element
- Select locally available materials for making atomic structure models
- Show creativity in designing atomic structure models

In groups, learners are guided to:

- Discuss types of atomic structure models that can be made (3D, 2D or computer-generated)
- Select two elements (a metal and a non-metal) with atomic numbers 1–20
- Draw sketches of atomic structures to guide model-making
- Collect locally available materials for the models

How can locally available materials be used to model the structure of an atom?

- Comprehensive Integrated Science Grade 9 pg. 16
- Locally available materials (e.g. clay, beads, wire)
- Exercise books, pencil

- Observation - Project work

Mixtures, Elements and Compounds

Structure of the atom - Atomic structure models

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

- Construct atomic structure models using locally available materials
- Label protons, neutrons and electrons correctly on models
- Show pride in presenting completed atomic structure models to peers

In groups, learners are guided to:

- Make atomic structure models (not more than 50 cm in length, width or height)
- Give protons, neutrons and electrons different colours; make protons and neutrons larger than electrons
- Label components correctly and indicate whether the element is a metal or non-metal
- Display and explain models to classmates; comment respectfully on others' work

What does a model of an atomic structure reveal about the element it represents?

- Locally available materials (clay, beads, wire)
- Paints or colour markers
- Exercise books

- Observation - Project assessment

Mixtures, Elements and Compounds

Structure of the atom - Atomic structure models

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

- Construct atomic structure models using locally available materials
- Label protons, neutrons and electrons correctly on models
- Show pride in presenting completed atomic structure models to peers

In groups, learners are guided to:

- Make atomic structure models (not more than 50 cm in length, width or height)
- Give protons, neutrons and electrons different colours; make protons and neutrons larger than electrons
- Label components correctly and indicate whether the element is a metal or non-metal
- Display and explain models to classmates; comment respectfully on others' work

What does a model of an atomic structure reveal about the element it represents?

- Locally available materials (clay, beads, wire)
- Paints or colour markers
- Exercise books

- Observation - Project assessment

Mixtures, Elements and Compounds

Structure of the atom - Atomic structure models

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

- Construct atomic structure models using locally available materials
- Label protons, neutrons and electrons correctly on models
- Show pride in presenting completed atomic structure models to peers

In groups, learners are guided to:

- Make atomic structure models (not more than 50 cm in length, width or height)
- Give protons, neutrons and electrons different colours; make protons and neutrons larger than electrons
- Label components correctly and indicate whether the element is a metal or non-metal
- Display and explain models to classmates; comment respectfully on others' work

What does a model of an atomic structure reveal about the element it represents?

- Locally available materials (clay, beads, wire)
- Paints or colour markers
- Exercise books

- Observation - Project assessment

Mixtures, Elements and Compounds

Metals and alloys - Physical properties of metals

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

- Define physical properties of metals
- Identify the physical properties of metals (state, lustre, hardness, malleability, ductility)
- Show interest in investigating the physical properties of metals

In groups, learners are guided to:

- Discuss the unique physical properties that differentiate metals from other substances
- Identify metals and non-metals in the environment
- Study the colour of different metal samples (iron, copper, aluminium) and record observations

How are alloys important in day-to-day life?

- Comprehensive Integrated Science Grade 9 pg. 20
- Samples of iron, copper, aluminium
- Exercise books

- Observation - Oral questions

Mixtures, Elements and Compounds

Metals and alloys - Physical properties of metals (malleability and ductility)

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

- Demonstrate malleability and ductility of metals through experiment
- Distinguish between malleable and ductile materials
- Collaborate effectively during experiments on metal properties

In groups, learners are guided to:

- Carry out an experiment to demonstrate ductility and malleability using an iron nail, aluminium wire, charcoal and pencil lead
- Record observations on change of shape after pounding and ability to bend
- Discuss and share findings with classmates

Why are some metals preferred over others for making specific items?

- Comprehensive Integrated Science Grade 9 pg. 20
- Hammer, iron nail, aluminium wire, charcoal, pencil lead, pliers, cloth

- Observation - Written tests

Mixtures, Elements and Compounds

Metals and alloys - Physical properties of metals (electrical conductivity)

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

- Investigate electrical conductivity of metals through an experiment
- Differentiate between conductors and non-conductors of electricity
- Appreciate the importance of electrical conductivity of metals

In groups, learners are guided to:

- Set up an electric circuit to investigate electrical conductivity of various materials (iron nail, aluminium foil, charcoal, copper wire)
- Record observations on whether each material is a conductor or non-conductor
- Share and discuss findings with classmates

Why are metals used in making electrical wires?

- Comprehensive Integrated Science Grade 9 pg. 20
- Dry cell, bulb, switch, connecting wire, crocodile clips
- Iron nail, aluminium foil, charcoal, copper wire

- Observation - Oral questions

Mixtures, Elements and Compounds

Metals and alloys - Physical properties of metals (thermal conductivity)

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

- Demonstrate thermal conductivity of metals
- Explain why metals are good conductors of heat
- Show interest in how thermal conductivity of metals affects everyday use

In groups, learners are guided to:

- Hold one end of metal and non-metal samples while exposing the other end to heat; note temperature rise
- Identify substances that conduct heat and those that do not
- Discuss why cooking utensils are made of copper or aluminium and handles of plastic or wood

Why are cooking pots made of metals but their handles made of plastic or wood?

- Comprehensive Integrated Science Grade 9 pg. 20
- Samples of iron, aluminium, copper, charcoal, wood, plastic
- Source of heat

- Observation - Oral questions

Mixtures, Elements and Compounds

Metals and alloys - Composition of common alloys

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

- Define the term alloy
- Describe the composition of common alloys (steel, stainless steel, bronze, brass, duralumin)
- Show interest in learning about how alloys are formed

In groups, learners are guided to:

- Discuss the meaning of alloy and how it differs from a pure metal
- Use digital or print media to search for the composition of brass, steel, stainless steel, duralumin and bronze
- Present and share findings with classmates

Why are alloys generally stronger and more useful than pure metals?

- Comprehensive Integrated Science Grade 9 pg. 26
- Internet access
- Reference books
- Charts on composition of alloys

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Metals and alloys - Composition of common alloys

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

- Identify the constituent elements of each common alloy
- Compare the composition of steel, stainless steel, bronze, brass and duralumin
- Appreciate the role of non-metals in forming alloys

In groups, learners are guided to:

- Discuss composition of brass (copper + zinc), steel (iron + carbon), stainless steel (iron + chromium + carbon), bronze (copper + tin), duralumin (aluminium + copper + magnesium)
- Record compositions in a comparison table
- Share work with group members and present to classmates

How does changing the composition of an alloy change its properties?

- Comprehensive Integrated Science Grade 9 pg. 26
- Internet access
- Reference books

- Written assignments - Observation

Mixtures, Elements and Compounds

Metals and alloys - Uses of metals and alloys in day-to-day life
Metals and alloys - Uses of alloys in day-to-day life

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

- Identify items from the locality made of common metals (sodium, magnesium, aluminium, copper, iron, gold, silver)
- Explain why specific metals are used for specific purposes
- Appreciate the economic importance of common metals in everyday life

- Identify items made of common alloys (brass, steel, bronze, duralumin, stainless steel) in day-to-day life
- Explain why specific alloys are used for specific purposes based on their properties
- Show appreciation for the importance of alloys in everyday life

In groups, learners are guided to:

- Identify items from pictures made of common pure metals
- Discuss the reasons items are made of pure metals based on their properties (e.g. aluminium for cooking pots due to thermal conductivity and corrosion resistance)
- Identify items from the school neighbourhood made of these metals

- Discuss uses of common alloys: steel (construction, cars, ships), brass (musical instruments, decorative items), stainless steel (utensils, surgical instruments), duralumin (aerospace)
- Identify alloy items from the school locality
- Share and discuss findings with classmates

Why are some items made of pure metals rather than alloys?
How do the properties of alloys make them more useful than pure metals for certain applications?

- Comprehensive Integrated Science Grade 9 pg. 27
- Pictures or samples of metal items
- Reference books

- Comprehensive Integrated Science Grade 9 pg. 27
- Pictures or samples of alloy items
- Internet access, reference books

- Oral questions - Observation

Mixtures, Elements and Compounds

Metals and alloys - Rusting (causes)

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

- Define rusting
- Identify the conditions necessary for rusting to occur (presence of iron, water and oxygen)
- Show curiosity in investigating the conditions necessary for rusting

In groups, learners are guided to:

- Discuss the meaning of rust and the conditions necessary for rusting
- Set up an experiment using three test tubes: one with anhydrous calcium chloride (dry air only), one with boiled water and oil (water without air), one with tap water partly covering the nail (air and water)
- Observe results after three days and discuss

What conditions are necessary for iron to rust?

- Comprehensive Integrated Science Grade 9 pg. 29
- Iron nails, test tubes, tap water, boiled water, cooking oil, anhydrous calcium chloride, rubber corks
- Test tube rack

- Observation - Oral questions

Mixtures, Elements and Compounds

Metals and alloys - Rusting (causes)

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

- Define rusting
- Identify the conditions necessary for rusting to occur (presence of iron, water and oxygen)
- Show curiosity in investigating the conditions necessary for rusting

In groups, learners are guided to:

- Discuss the meaning of rust and the conditions necessary for rusting
- Set up an experiment using three test tubes: one with anhydrous calcium chloride (dry air only), one with boiled water and oil (water without air), one with tap water partly covering the nail (air and water)
- Observe results after three days and discuss

What conditions are necessary for iron to rust?

- Comprehensive Integrated Science Grade 9 pg. 29
- Iron nails, test tubes, tap water, boiled water, cooking oil, anhydrous calcium chloride, rubber corks
- Test tube rack

- Observation - Oral questions

Mixtures, Elements and Compounds

Metals and alloys - Rusting (effects and prevention)

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

- Describe the effects of rusting on metals
- Suggest ways of preventing rusting of metals
- Show responsibility in identifying and reporting rusting in the school environment

In groups, learners are guided to:

- Study pictures of objects affected by rust and discuss the effects of rusting
- Identify places in the school neighbourhood affected by rusting
- Suggest different ways of controlling rusting (paint, electroplating)

What are the economic consequences of rusting and how can it be controlled?

- Comprehensive Integrated Science Grade 9 pg. 29
- Pictures of rusted objects
- Reference books

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Metals and alloys - Rusting (effects and prevention)

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

- Describe the effects of rusting on metals
- Suggest ways of preventing rusting of metals
- Show responsibility in identifying and reporting rusting in the school environment

In groups, learners are guided to:

- Study pictures of objects affected by rust and discuss the effects of rusting
- Identify places in the school neighbourhood affected by rusting
- Suggest different ways of controlling rusting (paint, electroplating)

What are the economic consequences of rusting and how can it be controlled?

- Comprehensive Integrated Science Grade 9 pg. 29
- Pictures of rusted objects
- Reference books

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Metals and alloys - Rusting (prevention methods)

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

- Explain specific methods used to prevent rusting (painting, galvanising, oiling, alloying)
- Compare the effectiveness of different rust prevention methods
- Appreciate the importance of preventing rusting to extend the life of metal objects

In groups, learners are guided to:

- Discuss methods of preventing rusting: painting, galvanising, oiling or greasing, alloying (e.g. stainless steel)
- Use digital or print media to find out more on rust prevention methods
- Evaluate the most practical methods in their community

Which method of preventing rusting is most practical and cost-effective in your community?

- Comprehensive Integrated Science Grade 9 pg. 29
- Internet access
- Reference books
- Pictures of rust prevention examples

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Metals and alloys - Rusting (prevention methods)
Metals and alloys - Gold and silver in day-to-day life

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

- Explain specific methods used to prevent rusting (painting, galvanising, oiling, alloying)
- Compare the effectiveness of different rust prevention methods
- Appreciate the importance of preventing rusting to extend the life of metal objects

- Describe the uses of gold and silver in day-to-day life
- Explain why gold is used in electronics and dentistry
- Appreciate the economic value of precious metals such as gold and silver

In groups, learners are guided to:

- Discuss methods of preventing rusting: painting, galvanising, oiling or greasing, alloying (e.g. stainless steel)
- Use digital or print media to find out more on rust prevention methods
- Evaluate the most practical methods in their community

- Discuss uses of gold: jewellery (lustre and resistance to tarnishing), electronics (electrical conductivity), dentistry (dental crowns and bridges)
- Discuss uses of silver and its alloys in day-to-day life
- Identify gold and silver items in the community and discuss their value

Which method of preventing rusting is most practical and cost-effective in your community?
Why are gold and silver considered precious metals and what makes them valuable in different industries?

- Comprehensive Integrated Science Grade 9 pg. 29
- Internet access
- Reference books
- Pictures of rust prevention examples

- Comprehensive Integrated Science Grade 9 pg. 27
- Internet access
- Reference books
- Pictures of gold and silver items

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Metals and alloys - Gold and silver in day-to-day life

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

- Describe the uses of gold and silver in day-to-day life
- Explain why gold is used in electronics and dentistry
- Appreciate the economic value of precious metals such as gold and silver

In groups, learners are guided to:

- Discuss uses of gold: jewellery (lustre and resistance to tarnishing), electronics (electrical conductivity), dentistry (dental crowns and bridges)
- Discuss uses of silver and its alloys in day-to-day life
- Identify gold and silver items in the community and discuss their value

Why are gold and silver considered precious metals and what makes them valuable in different industries?

- Comprehensive Integrated Science Grade 9 pg. 27
- Internet access
- Reference books
- Pictures of gold and silver items

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Metals and alloys - Gold and silver in day-to-day life

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

- Describe the uses of gold and silver in day-to-day life
- Explain why gold is used in electronics and dentistry
- Appreciate the economic value of precious metals such as gold and silver

In groups, learners are guided to:

- Discuss uses of gold: jewellery (lustre and resistance to tarnishing), electronics (electrical conductivity), dentistry (dental crowns and bridges)
- Discuss uses of silver and its alloys in day-to-day life
- Identify gold and silver items in the community and discuss their value

Why are gold and silver considered precious metals and what makes them valuable in different industries?

- Comprehensive Integrated Science Grade 9 pg. 27
- Internet access
- Reference books
- Pictures of gold and silver items

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Water hardness - Physical properties of water

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

- Describe the physical properties of water (taste, colour, odour and boiling point)
- Investigate the boiling point of water through an experiment
- Show interest in understanding the physical properties of water

In groups, learners are guided to:

- Add water in a transparent beaker, observe and note its colour and smell
- Place a thermometer into the water and heat to boiling; note the temperature at which it boils
- Collect and observe water from different sources and compare them in terms of appearance, odour, taste and boiling point

What is the importance of different types of water?

- Comprehensive Integrated Science Grade 9 pg. 34
- Distilled water or rainwater, 100 ml beaker, thermometer, source of heat
- Various water samples

- Observation - Oral questions

Mixtures, Elements and Compounds

Water hardness - Hard water and soft water in nature
Water hardness - Characteristics of hard and soft water

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

- Explain the meaning of hard water and soft water
- Identify the sources of hard water and soft water in nature
- Show curiosity in finding out about the sources of hard and soft water in the community

- List the characteristics of hard water (poor lathering, spots on utensils, metallic taste, blocking of pipes)
- List the characteristics of soft water (lathers easily, no spots, may taste salty)
- Appreciate the differences between hard and soft water in nature

In groups, learners are guided to:

- Search for information on the characteristics of hard water and soft water using digital or print media
- Discuss findings: hard water comes mainly from ground sources; soft water comes from rain, rivers and streams
- Write short notes and share with classmates

- Collect water samples from different sources (distilled, rainwater, tap, borehole, river, lake, sea water)
- Test each sample for colour, odour, taste (safe sources only) and ability to lather with soap
- Classify samples as hard or soft water and share observations

Why is hard water preferred for drinking?
What makes some water sources harder than others?

- Comprehensive Integrated Science Grade 9 pg. 35
- Internet access
- Reference books
- Water samples from different sources

- Comprehensive Integrated Science Grade 9 pg. 35
- Water samples from different sources
- Clear plastic bottles, bar soap pieces, small tins

- Oral questions - Observation

Mixtures, Elements and Compounds

Water hardness - Causes of water hardness

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

- Explain the causes of water hardness (presence of calcium, magnesium and their carbonate and sulphate salts)
- Describe how water acquires hardness from rocks and soil
- Show appreciation for how geology affects the quality of water

In groups, learners are guided to:

- Discuss how water flowing through the ground dissolves calcium, magnesium and their carbonate and sulphate salts from rocks and soil
- Use digital or print media to find information on why borehole water is usually hard
- Share findings with classmates

How does the source of water determine whether it is hard or soft?

- Comprehensive Integrated Science Grade 9 pg. 35
- Internet access
- Reference books

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Water hardness - Softening hard water by boiling

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

- Define water softening
- Soften hard water by boiling through an experiment
- Show interest in applying water softening methods in day-to-day life

In groups, learners are guided to:

- Discuss the meaning of water softening (reducing water hardness caused by calcium and magnesium minerals)
- Wash a handkerchief with tap water and then with boiled-and-cooled tap water; compare time taken and amount of soap used
- Describe the process of softening hard water by boiling to classmates

How does boiling change the hardness of water?

- Comprehensive Integrated Science Grade 9 pg. 37
- Bucket with tap water, empty buckets, handkerchief, source of heat
- One-litre jug, sufuria, laundry bar soap

- Observation - Oral questions

Mixtures, Elements and Compounds

Water hardness - Softening hard water by distillation

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

- Soften hard water by simple distillation through an experiment
- Describe the steps of the distillation process for softening hard water
- Appreciate the use of distillation as a method of purifying and softening water

In groups, learners are guided to:

- Mix tap water with table salt to make a solution; set up distillation apparatus (distilling flask, Liebig condenser, thermometer)
- Boil the salty water; collect the distillate and test it by adding soap and shaking
- Describe the process of softening hard water by distillation to classmates

Why does distillation produce soft water regardless of the original water source?

- Comprehensive Integrated Science Grade 9 pg. 37
- Distilling flask, Liebig condenser, thermometer, conical flask, rubber tubing, source of heat
- Table salt, tap water, bar soap

- Observation - Written tests

Mixtures, Elements and Compounds

Water hardness - Softening hard water by distillation
Water hardness - Softening hard water by adding washing soda

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

- Soften hard water by simple distillation through an experiment
- Describe the steps of the distillation process for softening hard water
- Appreciate the use of distillation as a method of purifying and softening water

- Soften hard water by adding sodium carbonate (washing soda) through an experiment
- Explain what happens when washing soda is added to hard water
- Show interest in chemical methods of softening water

In groups, learners are guided to:

- Mix tap water with table salt to make a solution; set up distillation apparatus (distilling flask, Liebig condenser, thermometer)
- Boil the salty water; collect the distillate and test it by adding soap and shaking
- Describe the process of softening hard water by distillation to classmates

- Add sodium carbonate to a hard water sample while stirring; note colour change and formation of a precipitate
- Filter the solution to separate the clear liquid from the precipitate
- Test the filtrate by adding soap and shaking; discuss and record observations

Why does distillation produce soft water regardless of the original water source?
How does sodium carbonate remove hardness from water?

- Comprehensive Integrated Science Grade 9 pg. 37
- Distilling flask, Liebig condenser, thermometer, conical flask, rubber tubing, source of heat
- Table salt, tap water, bar soap

- Comprehensive Integrated Science Grade 9 pg. 37
- Hard water sample, sodium carbonate (washing soda), stirring rod
- Beakers, filter paper and funnel, test tubes, source of heat

- Observation - Written tests

Mixtures, Elements and Compounds

Water hardness - Advantages and disadvantages of hard water

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

- Outline the advantages of hard water (good for drinking as it provides minerals; good for industrial use)
- Outline the disadvantages of hard water (soap scum, wastes soap, forms scale in pipes and appliances)
- Appreciate both the benefits and limitations of hard water

In groups, learners are guided to:

- Use digital and print resources to search for information on the advantages and disadvantages of hard water
- Discuss in groups: advantages (minerals beneficial to health, industrial use) and disadvantages (soap scum, wasted soap, scale deposits in pipes and appliances, metallic taste)
- Write short notes and share with classmates

Why is hard water considered good for drinking yet problematic for household use?

- Comprehensive Integrated Science Grade 9 pg. 41
- Internet access
- Reference books

- Oral questions - Written assignments

Mixtures, Elements and Compounds

Water hardness - Advantages and disadvantages of soft water

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

- Outline the advantages of soft water (lathers easily, efficient cleaning, no scale deposits)
- Outline the disadvantages of soft water (lacks essential minerals like calcium and magnesium)
- Compare the uses of hard water and soft water in day-to-day life

In groups, learners are guided to:

- Discuss advantages of soft water: lathers easily with soap (uses less soap), efficient cleaning (no deposits), no scale in pipes and appliances
- Discuss disadvantages: lacks minerals beneficial to health
- Identify pictures showing applications of hard water and soft water; discuss other uses in day-to-day life

In what situations would soft water be preferred over hard water?

- Comprehensive Integrated Science Grade 9 pg. 41
- Internet access
- Reference books
- Pictures showing applications of water

- Oral questions - Written assignments