QUESTIONS

Social Studies

Use the map of Kimbo Area to answer questions 1 - 4.

1. What is the climate of the North Eastern region of Kimbo Area? (1 mark)
2. Who is the head of Kimbo Area? (1 mark)
3. What is the religion of the people in Kimbo Area? (1 mark)
4. River Enda flows towards which direction? (1 mark)
5. List any 2 elements for a map. (2 marks)
6. A compass has how many cardinal points? (1 mark)

Use the map of Kenya below to answer questions 7 - 10:

7. The country that boarders Kenya marked K is (1 mark)
8. The lake marked M is called (1 mark)
9. The mountain marked L is known as (1 mark)
10. The lake marked N is known as  (1 mark)
11. What is weather? (1 mark)
12. What is climate? (1 mark)
13. List any 4 historic built environments in Kenya. (4 marks)
14. List any 3 methods of instruction used in traditional education in promoting values. (3 marks)
15. List any 2 administrative leaders in a school.(2 marks)
16. Outline any 4 duties of administrative leaders in school. (4 marks)
17. List 4 language groups in Kenya. (4 marks)

Assessment Rubrics - Social Studies 

C.R.E

1. Outline 3 lessons that we can learn from the parable of the talents. (3 marks)
2. Identify any 3 responsibilities given to human beings by God. (3 marks)
3. Give 4 causes of child labour. (4 marks)
4. Give 4 lessons learnt from the fall of human beings in the garden of Eden. (4 marks)
5. List the 3 members of a nuclear family. (3 marks)
6. State 2 uses of the Bible. (2 marks)
7. List down the first 5 books of the New Testament of the Bible. (5 marks)
8. Give two good qualities learnt from the story of Peter and John at the temple. (2 marks)
9. Name the three sons of Noah. (3 marks)
10. Prophet Elijah held a contest with the false prophets of Baal at Mount (1 mark)

Assessment Rubrics - CRE

MARKING SCHEME

SOCIAL STUDIES

1. Cool and wet
2. Governor
3. Christianity
4. South West
5. Frame, title, key, compass
6. 4
7. Somalia
8. Turkana
9. Kenya
10. Victoria
11. Daily changes in the atmosphere
12. Average changes in the atmosphere over a long period of time 
13. Museum, monuments 
14. Proverbs, stories, riddles 
15. Headteacher, prefect, deputy headteacher
16. -Ensuring the school is clean
    -Ensuring the school is safe
    -Ensuring learners are following set rules
    -Punishing learners who break laws
17. Nilotes, Cushites, Bantus, Semites

C.R.E

1. -We should use our abilities well
   -We should be honest
   -We should be hardworking
2. -Taking care of God's creation
   -Giving birth
   -oberying God's commandments
3. -Poverty
   -Lack of parental care
   - Death of parents
   - Peer influence
4. -We should be obedient
   - We should follow God's commands
   - We should tell the truth always
   -Sin separates us from God
5. Mother, father, children
6. -Reading to learn God's word
   - Reading in school when learning C.R.E
7. Matthew, Mark, Luke, John, Acts
8. Faith, courage
9. Shem, Ham, Japheth
10. Carmel

• Solid waste management
  • Identifying solid waste
  • Classifying waste.
  • Ways of managing solid waste

Solid waste management

Identifying solid waste

• Solid waste is a type of waste that consists of everyday items that are thrown away by people.
• Solid waste is also known as rubbish, garbage or trash
• Solid waste comes from our offices, homes, schools, industries and hospitals among other places.
• Solid waste management is the process of collecting, treating and disposing of solid waste. It's about how solid waste can be changed and used as a valuable resource.

Classifying waste.

• Wastes are classified as both those that decompose easily and those that do not decompose.
• For example:
• Tomato fruit brakes down and starts to rot and eventually becomes part of soil. This is called decomposition.
• The plastic bottle did not show any change after a week. Therefore, the plastic bottles do not rot. It cannot decompose.

Ways of managing solid waste

• Different types of waste are managed differently. These ways include the 3Rs - Reusing, Recycling and Reducing.

1. Reusing
   • Some solid waste can be used again for their original purpose or for different work. For instance, discarded bottles can be cleaned and used for bottling drinks, or used at home for other tasks.
   • Other reusable solid waste include boxes, bags, old clothes, books, old newspapers and wood.
2. Recycling
   • Recycling solid waste means that the material is reprocessed before being used to make new products. All types of organic waste can be recycled by composting. Other solid wastes that can be recycled include paper, waste metals, glass and plastic bottles, among others.
3. Reducing
   • Waste reduction is a set of processes and practices intended to reduce the amount of waste produced. It is a way of preventing materials from ending up as waste. This can be done by buying products with less packaging, making use of reusable rather than disposable items, using your own shopping bags, minimizing food waste and repairing and maintaining items such as clothing, so that they last long. Solid waste can be reduced through the following ways
     1. Avoiding using plastic bags to carry items. Instead use baskets.
     2. Using reusable (canvas) bags for buying items
     3. Borrowing, renting or sharing items that are not regularly used.
     4. Using sponges or dish clothes instead of paper towels.
     5. Using plug-in appliances instead of battery 0perated gadgets.
     6. Buying durable and repairable products.

Project

1. Making dustbins using locally available materials
2. Make a toy car

• Components of Environment.
  • Major components of the environment.
  • Minor Components of the environment .

Environment is what surrounds an organism

Components of Environment

Major Components of the Environment.

• Water-Occupies the largest percentage
• Soil
• Air-Found in all other components of the environment
• Animal
• Plants

Minor Components of the Environment.

• Heat
• Sound

• Physical Environment
  
  • Types of Environment
• Map Reading And Intepretation
  • Elements of a Map
    • Use of Elements of a Map
  • Map Reading
  • Features That Can Be Interpreted From a Map
    • Human Activities Commonly Found in a Map
    • Features on a Map That Represents Administration
    • Features That Show Drainage Systems on a Map
  • Human Settlement on the Map
    • Types of Settlement
  • How to Identify Functions of a Town on a Map
• Physical Features
  • Effects of Physical Features of Human Activities
  • Negative Effects of Physical Features
• Climate
  • Traditional Methods of Observing Weather
  • Observation, Measurement and Recording of Weather Elements
    • Wind
    • Air Pressure
    • Rainfall
    • Temperature
  • Factors Influencing Climate Change
  • Impact of Climate Change on Human Activities
• Soil
  • Major soil types in Kenya
  • Characters of types of soil
    • Volcanic Soil
    • Clay(Black Cotton) Soil
    • Sandy Soil
    • Loamy Soil
    • Alluvial(Young) Soil
  • Major causes of soil erosion
  • Effects of Soil Erosion on Human Activities
  • Soil Conservation Measures

Physical Environment

What is Environment?

The things around us or in our surrounding make up the environment.
Examples

1. Trees
2. Animals
3. Water etc.
4. Grass
5. Rivers
6. Buildings
7. Birds

Types of Environment

1. Natural environment
   These were things that were made by God. E.g Mountains ,Lakes, Rivers, Vegetation etc.
2. Human environment
   These are things made through man`s efforts e.g Dams, buildings, roads, etc.
3. Physical environment
   The non – living part of the environment which consists of Soils, air, rocks, water, hills, mountains, rivers and lakes form the physical environment.

Map Reading And Interpretation.

A map is a drawing on a flat surface that represents a whole part of the earth.

Elements of a Map

Elements of a map helps a reader to understand the information on a given
map.
The main element of a map are:

1. Title
2. Key
3. Compress
4. Frame
5. Scales

Uses of Elements of a Map

Map Reading

This is the ability to read, understand, and interpret information given on a
map.
Symbols of a map contained in the key should be fully understood and
interpreted correctly.

Features That Can be Interpreted From a Map

1. Relief and drainage patterns in the area.
2. Human and economic activities in the area.
3. Types of climate experienced in the area.
4. Transport facilities in the area.
5. Vegetation found in the area.
6. Human settlement pattern in the area.
7. Administrative boundaries in the area.
8. Social activities (services) found in the area.

Human Activities Commonly Found in a Map

Economic activities are the objectives that people carry out in order to get
income (money).
Examples

Social Activities on a Map

1. Religious activities : Churches, mosques, temples, shrines.
2. Medical services : Clinics, dispensaries, health centers, district hospital, provincial hospitals and National hospitals.
3. Education: Schools, colleges, polytechnics, universities.
4. Recreation : Cinema halls, Social halls, play grounds, theatres.

Features on a Map That Represents Administration

1. Government offices e.g. Assistant chief`s offices or chief`s camp.
2. Police post.
3. Administrative boundaries.

Features That Show Drainage Systems on a Map

Human Settlement on the Map

Settlement is the pattern of population distribution in an area shown by dots and black shades.

Types of Settlement

How to Identify the Functions of a Town on a Map

Physical Features

These are things we see on the surface of the earth. They include natural physical features and man-made(human)

Natural features: Mountains, plateaus, hills, plains, valleys, rivers, lakes, etc.

Man-made: dams, lakes etc.

The Effects of Physical Features on Human Activities

Negative Effects of Physical Features

1. Flooding.
2. Water borne diseases e.g. Malaria and Bilharzia.

Climate

Traditional Methods of Observing Weather

1. Observing the sky
   • Thick grey clouds: rain.
   • Certain stars arranged in a particular manner: dry spell.
2. Phases of the moon
   • New moon: rain.
   • Full moon: It would rarely rain.
3. Appearance of the rainbow
   • Some communities believed that it would not rain if the rainbow appears in the sky when it was about to ran
4. Condition of the environment
   • Very hot and humid: Coming of the rain.
5. Blowing of wind
   • Strong winds blowing after a dry weather: Showed the coming of the rains
   • Wind blowing during the rainy season: Meant chasing away of the rain to give way to a dry spell.
6. Behavior of birds:
   • Happy and playful birds in the sky would signify the coming of rains.
7. Trail of ants: Signified the coming of rains.
8. Croaking of frogs: Signified the coming of the rain.
9. Appearance of toads: Signified the coming of the rains.
10. Behavior of cattle: Coming of the rains(showing happiness by jumping up and down)
11. Shedding of leaves after a rainy season: This Signified a dry spell.

Observation, Measurement and Recording of Weather Elements

What is meteorology?

It is the science of observing and measuring weather elements.

1. Wind

   
   
   
   
   

2. Air Pressure

   
   
   
   

3. Rainfall

   
   
   The raingauge is dug into the ground as shown above.
   
   

4. Temperature

   
   
   1. Minimum and maximum thermometer
      
      
      Used to measure temperature for the day.
      It is U-shaped.
      Minimum records coldest temperature.
      Maximum records warmest temperatures.
      
      
   2. Single-tube thermometer
      
      
      Used to measure coldness and / or hotness of the air.
      It is marked in o Celsius.
      It may contain alcohol or mercury.

Factors Influencing Climate Change

Climate change is the occurrence of unexpected change of climatic condition in a particular region. The main factors influencing climate change include:-

1. Deforestation
   Cutting down of trees leads to reduced amount of rainfall.
   It creates desert – like conditions in the areas previously occupied by forests.
   It contributes to increased carbon dioxide in the atmosphere.
   
   
2. Afforestration and re-afforestration
   Planting of more trees will increase the amount of rainfall.
   Both afforestration and re-afforestration reduce soil erosion and evaporation, hence protecting water catchment areas.
   
   
3. Industrialization
   Heat and smoke from industries cause pollution and increase temperature in the atmosphere.
   
   
4. Excess use of chemicals
   Such as fertilizers causes atmospheric change due to the gasses they produce.
   The growing of rice under irrigation contributes to warming of the atmosphere. The rice in water release a gas known as methane, which
   contributes to global warming. The same applies to the use of fertilizers.
   Global warming is also caused by the use of petroleum to run vehicles .Machines give off a gas known as carbon monoxide, which makes
   the air warmer.
   
   
5. Clearing of vegetation for agriculture
   This exposes the soil to agents of soil erosion.
   
   
6. Building of dams
   Human-made lakes which form behind the dam modify the climate.
   
   
7. Ocean currents
   These leads to temperature change along the coastal areas.

Impact of Climate Change on Human Activities

Positive effects

1. Increase in food production due to increased amount of rainfall
2. Increased generation of hidro-electric power due to high rainfall.
3. Promotion of fishing due to adequate water in rivers.

Negative effects

1. Low agricultural production due to lack of rains.
2. Displacement of people due to floods.
3. Global warming as a result of general increase in temperature worldwide.
4. Increase of water-borne diseases such as malaria and bilharzias due to increased rains.
5. Damage of transport systems e.g. roads.
6. Migration of people migration of people to favourable climate.
7. Death of human beings.

Soil

Soil is formed through a process called weathering. Soil contains:

1. Organic matter
2. Rock particles
3. Humus
4. Air
5. Minerals
6. Water
7. Living organisms

Major Soil Types in Kenya

1. Volcanic soils.
2. Clay (black cotton) soil.
3. Sandy soil.
4. Loamy soil.
5. Alluvial (young) soil.

Characteristics of Types of Soil

Volcanic Soil

1. Red in colour.
2. Deep fertile and well-drained.
3. Occur in layers.
4. Medium – sized soil particles.
5. Mainly found in the highlands.

Clay( Black Cotton) Soil

1. Small – sized particles.
2. Dark in colour
3. Deep and fertile
4. Poorly drained.
5. Muddy and sticky during the rainy season.
6. Big cracks during dry seasons.

Sandy Soil

1. Large soil particles.
2. Shallow and dry.
3. Contains a lot of air.
4. Water seeps through them fast.
5. Low water retention capacity.
6. Loose nutrients mainly through leaching.

Loamy Soil

1. It has a mixture of small, medium and large soil particles.
2. It retains a reasonable amount of water fertile, deep and well drained.
3. Appears in different colours e.g. light grey, dark brown and dark grey.

Alluvial (Young) Soil

1. They are found in river valleys and flood plains.
2. They are made of slits.
3. Soil particles are of medium size.
4. Have a smooth texture.
5. They are deep and fertile.

Major Causes of Soil Erosion

Soil erosion is the natural displacement of soil from the original place of formation to another by agents of erosion like wind, water and human beings.

The major causes of soil erosion are as follows:

1. Deforestation- Cutting down of trees which exposes the soil to agents of soil erosion.
2. Overstocking- Keeping large herds of livestock beyond the capacity of land leading to overgrazing
3. Overgrazing-Livestock grazing on all pasture (vegetation) leaving the ground bare.
4. Monocropping-Growing of one type of crop on the same peace of land year after year exhausts soil fertility.
5. Over-cropping-Growing of many different types of crops which compete for nutrients. The soil finally becomes loose and infertile
6. Up-the-slope (hill) cultivation-This promotes gulley erosion.
7. Mining and quarrying-Results to displacement of soil.

Effects of Soil Erosion on Human Activities

1. Destocking (reducing the number of livestock on the farm)
2. Application of fertilizers to the soil in order to increase its fertility.
3. Introduction of afforestration and re-afforestrationprogrammes
4. Promotion of agriculture in the flood plain where fertile soil (alluvial) is deposited.
5. Adoption of good farming methods to reduce soil erosion.
6. Additional expense to the government in building dams, dykes and canals.

Soil Conservation Measures

1. Afforestration :
   Planting of trees.
2. Re- afforestration:
   Planting of trees where they had been cut down.
3. Agro-forestry:
   Planting of trees together with crops.
4. Crop rotation:-
   Growing of different crops on the same peace of land in alternate planting seasons.
5. Mulching: The covering of the bare ground with grass to prevent moisture loss.
6. Cover cropping:
   Planting of perennial crops like coffee and bananas together with food crops likepotatoes, beans and maize.
7. Construction of gabions:
   Pilling up of stones in iron cages to prevent further movement of soil downhill.
8. Terracing:
   Making of horizontal steps on sides of hilly areas.
9. Fallowing:
   Leaving the land idle for some time in order to retain its fertility.
10. Creation of cut-off- drainage:
    This is the digging of trenches to divert water from hill tops
11. Controlled grazing:
    This is done by subdividing land into paddocks.
12. Use of fertilizers and manure:
    This helps the soil to regain its fertility.
13. Contour ploughing:
    This is ploughing of farm across the land guarded by the contours.

• The Meaning and Major Components of Environment
• The Meaning and Effects of Soil Pollution.
  • Effects of Soil Pollution
  • Methods of Soil Conservation
• Air Pollution
  • Major Causes of Air Pollution
  • Effects of Air pollution on Living and Non-living things
  • Ways of controlling air pollution

The Meaning and Major Components of Environment

Environment describes all the things and conditions that make up our surroundings on earth.

The major natural components of environment consist of living things and non-living things i.e. Water, Soil, Air, Plants and Animals

Water

Water is a very important component of the environment in that all living things depend on water. Water forms part of the environment for fish as fish get oxygen from the water and feed on water plants or some other fish found in the water. All other living things that live in water get oxygen from the water.

Other water sources found in the environment is a dependent for other living things on the land e.g. animals get water from rivers, lakes, rain and dams. People also use rain water for domestic purposes. They harvest the water using tanks and drums. They also
fetch water from rivers and wells.

Without water plants can not grow well. We already know that the conditions necessary for germination are: water, air and warmth. During photosynthesis, plants use water to make their own food.

Soil

Another important component of environment is soil which makes the homes of some small animals. Plants get nutrients from the soil so as they can grow well, get water from the soil through absorption and are finally held by the soil. Also soil is important to
animals in that they feed on plants that grow on the soil e.g. zebra, cows and goats. They are called herbivorous because they feed on green plants and vegetable materials that grow on the soil. Human beings cultivate the soil to produce food crops that they eat.

Many small animals live in the soil like ants, termites, moles, groundhogs and some bacteria which decompose dead plant and animal materials.

Air

One of the major components of the environment is air which all living things cannot survive without. We already know that air is a composition of many gases; oxygen which makes 21% of the air is needed for respiration.

Note that living things breath in oxygen and those animals that live in water get their oxygen from the dissolved oxygen in the water. Carbon dioxide in air is 0.03% which is used by plants in making their own food in presence of sunlight, a process called
photosynthesis. These plants give out carbon dioxide. It is from the atmosphere where the plants and animals on the land get their oxygen and those in water get theirs in the water.

Animals take in oxygen through breathing and give out carbon dioxide. On the other hand plants take in carbon dioxide during photosynthesis and give out oxygen. Leguminous plants e.g. beans, ground nuts and peas use nitrogen which makes 78% part
of the air to make proteins.

Plants

Another major component of the environment is plants. Trees provide shelter for some animals such as monkeys and insects. Animals get their food from plants either directly or indirectly. Plants do also hold soil together thus preventing soil erosion.
Plants give out oxygen to the atmosphere during photosynthesis and animals take in oxygen during breathing. Dead plants decay and decompose releasing nutrients to the soil making it fertile.

Animals

Some animals help in pollination such as bees and butterflies. They help in cross pollination of flowers in plants. Animals also help in seed dispersal. Waste matters from animals add nutrients to the plants and this way soil becomes fertile. Small animals like
bacteria decompose materials in the environment to release nutrients to the environment. Animal breath out carbon dioxide into the atmosphere which in turn is used by plants to make food.

The Meaning and Effects of Soil Pollution

Soil pollution is the presence of substances that affect the quality of the soil also known as land pollution. It affects the usual use of soil and is dangerous to the health of human beings, other animals and plants. In other words, soil pollution means making soil impure. We say that when certain substances are present in the soil they pollute it. Substances that make soil or other components of the environment impure are called pollutants (contaminant). Some of examples of such pollutants are plastics, polythene papers, fertilizer, pesticides and herbicides.

NB: Pesticides kill pests while herbicides kill weeds.

If oil is spilled on the soil it pollutes it. The following are some causes of soil pollution:

• Domestic waste disposal improperly
• Improper disposal of raw industrial waste
• Excess use of fertilizers, herbicides and pesticidesin the activities of poor agriculture
• Spilling oil on the soil
• Mining activities destroysthe soil structure and leave excessminerals on the top soil.

Effects of soil pollution

When soil is polluted, its fertility is affected and this too affects the soil productivity leading to the living components of the environment i.e. plants and animals getting affected as well.

Effects of soil pollution on plants

Dumping

Most materials such as plastics and polythene papers do not decay. If such materials are not properly dumped, they may cause damage to leaves and stems of plants when deposited on the soil as they decay. Through this way, they interfere with growth of the plants as follows:

• Absorption of water and mineral salts.
• Growth of roots of the plants since they block the roots.
• Air circulation in the soil.

Negative Effects of Soil Pollution on Animals.

Soil being homes of many small animals, such as worms, ants and termites, they are negative affected when soil is affected (polluted). Some small animals like bacteria make soil to be rich by decomposing dead vegetable and animal materials. Thisis the way humus is added into the soil making it more productive. Other small animals like earthworms and millipedes dig in the soil and this allows air and water circulation in the soil. The improved soil aeration and drainage of the soil allows the roots of the plants to penetrate into the soil easily.

The presence of oil, chemicals in the soil such as herbicides and pesticides and other harmful pollutants make it difficult for the small animals to survive and when they die the soil losesits quality and lowers productivity.

NB: Small animals in the soil improve soil air aeration and drainage.

Methods of Soil Conservation.

Animals and plants depend on soil. Plants grow on the soil while animals feed on the plants hence they need to conserve soil. To conserve soil means to protect it from losing its natural properties and productivity. There are various methods of conserving soil. This section briefly discusses these methods.

Table 3.1: Summary of the main methods used in soil conservation

Methods used in soil Conservation

1. Control use of agricultural chemicals
   Agricultural chemicals include the following: fertilizers, pesticides and herbicides. If used uncontrollably they can lead to soil pollution and even water pollution. Their use can also be harmful to crops and those who consume the crop which include animals and human beings.
   Farmers should strictly follow the manufacturer’s instructions while using the agricultural chemicals. The instructions which come with agricultural chemicals clearly advise on the following:
   • Type of the chemical to use.
   • Purpose of the chemical.
   • Direction of usei.e. the amount to use and mode of application.
   • Precautionary measures to observe.
2. Ensuring proper disposal of waste
   A lot of waste is produced by domestic and industries. Both wastes can be harmful or useful. So that soil is not polluted by these wastes it is important to have good ways of disposing them. This is called waste management.
   1. Domestic Waste
      Domestic waste means the garbage people discard from their homes. This may be of organic refuse or inorganic refuse.
      
      Organic refuse: This refers to those that can rot and includes food remains, vegetables, and fruit peelings.
      
      Inorganic refuse: This does not rot and some may take long time to decay.
      Examples of such are plastics, broken glasses, metal parts and cans. Domestic
      waste should not be dumped on the soil surface.
      
      Methods of disposing domestic waste
      Converting waste into compost manure
      A compost pit should be dug at home for all garbage that can rot e.g. food leftovers. This can be made into compost manure
      
      Using local authority service
      Waste in urban areasis deposited into the garbage bins provided by the local authorities who arrange for its collection and thereafter proper disposal.
      Table 3.2:common methods of waste disposal
      

      Method	Description
      Incinerator	this is burning the inorganic refuse at very high temperatures in a machine
      Recycling	This is the most effective method. It involve collecting waste e.g. papers, plastics, broken glasses and food cans, treating them with chemicals and reusing them to make more of the same products
      Depositing in pit latrines	Inorganic waste should be thrown into a pit latrine or buried deep in the soil. Also it can be burnt in an improvised incinerator as shown below.
      Reusing	Reusing means using an item more then once or for a different function from the one it was meant for at the beginning. Many such as cooking fat and oils, honey and jam are packed in reusable jars and cans. These can be used at home to store other products e.g. salt, sugar or small foods. Honey jars can be used as drinking glasses.

   2. Industrial Waste
      A lot of waste is produced in the industries. Such wastes include oil, contaminated acids and metal waste. Water is contaminated with chemicals, waste rubbers and waste papers. Some of these chemicals are not only hazardous to the soil but to the living component sin the environment.
      

      Method	Description
      On-site treatment	This is where waste is treated harmless at an industry at the point where it is produced. This in turn reduces the danger of polluting the environment during the transportation process to the point where it is appropriate to be disposed.
      Reusing	Some industries use some products more than once or for different function from the initially meant for e.g. commercial industries, the solvent they use such as petrol to dry clean garments is not thrown away but filtered and reused.
      Recycling	Companies that make bottles do not throw broken bottles away but recycle them to make new ones. There are other companies that buy waste paper and recycle them to make tissues e.g. toilet rolls, facial tissues and serviettes.
      Waste Exchange Programme	One industry may produce waste that can or may be needed by another industry for its raw materials. This can be considered as useful waste. To explain this lets look at furniture manufacturer where the saw dust is produced and wood shaving as waste products. These can be used by a company that manufactures papers.
      Treating hazardous waste	This is where the new methods are used to treat hazardous waste to make them non-hazardous. Harmful pollutants are destroyed so that they do not pose any danger to the environment.
      Substituting raw materials	This is the process where the raw materials that produce harmful wastes are replaced with other that produces less harmful waste.
      Changing Manufacturing process	A process or stage which produces waste during the manufacturing process may be changed or eliminated so that the waste is no longer produced.
      Incineration	This is the process of burning waste using machines such as incerators and furnaces.
      Reducing its generation	This is the best method of reducing waste. It involves simply preventing waste generation.
      Government regulations	In this, government has put in place laws to control the disposal of waste. Such control aims at preventing illegal dumping of harmful waste.

3. Avoid burning vegetable cover
   When we want to clearland for farming, we should slash or uproot the unwanted vegetations but not burning them. This is because cleared vegetation left to rot increase humus and adds nutrients to the soil.
   
   NB: Vegetation cover guards soil against exposure to the agents of soil erosion.
   
   When we burn vegetation, we kill the living organisms in the soil and no humus goes into the soil. Vegetation cover also prevents soil from agents of soil erosion such as wind, water and animals.
4. Mulching
   This is covering the soil with dead plant materials such as dry grass and leaves. This prevents excessloss of water from the soil through evaporation. This also reduces splash erosion. The mulch decays afterwards and adds humus to the soil.
5. Planting ground cover
   It is advisable to plant ground coversince land should not be left bear. Ground cover may include ground cover crops that spread out overthe soil surface and cover it. Examples of such cover crops include grass and sweet potatoes. These crops or plants hold the soil firmly with their roots helping or preventing the soil from being carried away by agents of soil erosion such as wind and rain. Cover crops also trap soil as water flows through the garden thus conserving soil.
6. Terracing
   Terraces dug along the contours on the slopes reduce the speed of run-off water. This reduces soil erosion and this way soil is conserved.
7. Planting trees
   Planting of trees can be either afforestation or re-afforestation.
8. Afforestation
   This is planting of trees in areas where none has been planted.
9. Re-afforestation
   This is planting trees where forests have been cleared. Trees are important in preserving soil:
   
   • Reduce wind erosion by breaking the wind
   • The roots hold soil particlesfirmly together. This helps the soil from being carried away by agents of soil erosion.
   • They provide shade thus reducing the amount of water evaporation.
   • They reduce the speed of running water. This reduces the strength of water to erode the soil.
   • The leaves fall off and decompose thus increasing the amount of humus in the soil.
10. Contour farming
    In this crops are planted along the contours on ridges. This helps reduce soil erosion thus conserving the soil.
11. Building gabions
    As already known, gulley erosion where running waterforms V or U - shaped channels. These gullies can be blocked by building structures called gabions across them. Gabions are heavy boxes made of wire mesh that are filled with stones. As water flows through the gabion, soil is trapped thus reducing soil erosion and repairs the soil structure.
12. Proper stocking or controlled grazing
    Farmers should keep livestock that a piece of land can hold. This is called proper stocking which leads to soil conservation. When animals overgraze they uproot the vegetable cover e.g. grass. This way the soil becomes exposed to agents of soil erosion such as wind and water.

Air Pollution

Air is an important component of the environment. Pure air is a mixture of 21% oxygen, 78% nitrogen, 0.03% carbon dioxide and 0.97% rare gases, water vapour, and dust particles. Presence of harmful substances in the air is called air pollution. The substances are called pollutants. Pollutants endanger human health and also affect other living components in the environment i.e. plants and animals. Others which arte indirectly affected by air pollution are water and soil.

Major causes of air of Pollution

1. Tobacco smoking
   This is one of the major forms of air pollution. It is normally smoked as cigarettes. In addiction to nicotine and tar, tobacco contains carbon monoxide as well which is a highly poisonous gas as it interferes with the ability of the blood to transport oxygen to the body organs. Smoke from cigarettes does not only affect the active smoker but also the passive smokeri.e. any one who inhales the cigarette smoke (polluted air) unintentionally.
2. Burning tyres and plastic materials
   The combustion of tyres and plastic materials produces harmful emissions and poisonous gases and especially when they do not completely burn. Incomplete combustion produces gases such as carbon monoxide which poses threat to humans health and to the survival of animals and plants. Similarly, carbon dioxide is a product of incomplete combustion. As we already know the normal carbon dioxide in the air is 0.03% excess carbon dioxide in the air as pollutant. Other pollutants from combustion are tiny particles of smoke and soot.
   
   Rubber and plastics when burnt produces black sooty flame and emits smoke that makes the air smoggy and also emits a foul smell. Charcoal burning is also a threatto the environment
3. Emission of Gases from Vehicle Exhaust
   Vehicles use fuels like petrol and diesel to run. The combustion of these fuels in the engine of the vehicles produces harmful gases e.g. carbon dioxide, carbon monoxide and other gases. These gases produced by vehicles contain poisonous gases then contribute to pollution of the air. Exhaust gases from vehicles thus contribute to pollution of air and especially in cities and big towns where traffic is heavy.
   
   Another harmful substance that may be contained in burning fuels is lead which is dangerousto human health.
4. Spraying Farm Chemicals
   Agricultural or otherwise farm chemicals include the following: Herbicides, Acaricides and Pesticides
   
   Farm chemicals are dissolved in water and sprayed to either crops or animals using a sprayer. As spraying farm chemical is done, wind blows some of the chemicals thus polluting the air. The person spraying the chemicals should take the following precaution measures to avoid inhaling the chemicals:
   
   • Wearing protective clothessuch as gas mask, gloves and protective coats.
   • Spraying in the same direction the wind is blowing to and not against the wind.
5. Aerosol sprays
   These are packed in cans or other containersfrom which liquid is forced out in form of a fine mist. The perfume or pesticide is dissolved in solvent which remains in the atmosphere after spraying and pollutes it. The solvent may contain harmful chemical substances which interfere with the ozone layer.
   
   NB: Ozone is a gasin the upper part of the atmosphere. It forms a protective blanket known as the ozone layer which protects the earth from harmful rays from the sun. Harmful gases result in tuning of the ozone layer. When this is depleted, the survival of human being, animals and plants is at a threat.
6. Industrial Waste Gases
   Most industries release waste gases into the air which may be harmful. Some of these industries produce excess carbon dioxide which can pollute the air. Some otherindustries produce a gas called sulphur dioxide which is also harmful. Other industries too produce dust and small particles which are harmful. These waste industrial gases must be treated so that they are made safe.

Effects of Air Pollution on Living Things and Non-Living Things

Polluted air is a threat to human, animals and plant life. Also it is dangerous to nonliving components of the environment e.g. water and soil. It corrodes materials such as corrugated iron sheets and marble.

1. Effects of air pollution on living things

   1. Effects of air pollution on plants
      In order to grow healthy, plants need clean air. Polluted air affects plants in the following ways:
      • Leaves are covered with dust particle and thus blocking the sunlight and so affecting photosynthesis, the process by which plants make their own food. Soot and dust block the stomata this may affects plants.
      • Some waste gases such as sulphur dioxide dissolve in water droplets to form acidic solutions which damage leaves of plants. Presence of these gases in the air could also lead to formation of acid rain which make the soil to be acidic thus affecting the availability of nutrients to plants. High acidity on the soil may interfere with the survival of organisms that are very important to plants growth. When absorbed through roots, acid rain interferes with proper development of plant and it may wither and die. When deposited in water sources like pond, lakes and oceans, water plants that feed on water animals are affected.
   2. Effects of air pollution on animals
      Air pollution is a threat to humans, domestic and wild animals through the following ways:
      • Causes respiratory problems. When animals inhale dust and other harmful gases, they can develop respiratory such as coughing and sneezing which may result to respiratory diseases.
      • May cause allergies resulting in coughing, sneezing, irritation of eyes and breathing problems.
      • When acid rain gets deposited into water sources like lakes, ponds, and oceans, water animals e.g. fish are affected.

2. Effects of air pollution on non living things

   • Sulphur and carbon dioxide are among gases that cause air pollution when dissolved in the rain water. They form acid rain which corrodes metals such as corrugated iron sheets and stones like marble.
   • Acid rain causes weathering of rocks.
   • The view of environment is also destroyed by smoke and smog which are a mixture of gas particles.
   • Smog destroys materials made of rubber too.
   • Dust particles soil our clothes and settle on surface of tables, window sills and furniture thus making then dirty.

Ways of Controlling Air Pollution

Air pollution is controlled in several ways: These include;

• Avoiding smoking cigarettes
• NOT burning tyres and plastic materials

Table 3.4: Air Pollution Control Measures