• Composition of Air
• Components of Air
  • Uses of Oxygen
  • Uses of Carbon Dioxide
  • Uses of Nitrogen
  • Uses of Inert Gases

Composition of Air

Air is a mixture of gases

Air mainly consists of :

• Gases
• Water vapour
• Dust particles

Components of Air

Uses of Oxygen

• Breathing ( Respiration)
• Germination
• Burning ( Combustion)
• Rusting.

Uses of Carbon Dioxide

• Photosynthesis
• Preserve soft drinks
• To make fire extinguishers
• Used in baking
• Used in making dry ice.

Uses of Nitrogen

• Used by plants to make proteins
• Used to preserve semen
• It is taken in through the roots as nitrates. Leguminous plants are able to convert nitrogen to nitrates.

Uses of Inert Gases

• They include Argon, Neon, Helium and Krypton
• Used in electric bulbs and light tubes
• Used in coloured advertising signboards.
• Used in hot air balloons.

• Light
  • Transparent Materials
  • Translucent Materials
  • Opaque Materials
• Reflection of Light
  • Types of Reflections
• Refraction of Light
  • Effects of Refraction

Light

How light travels

• Light travels in a straight line away from the source.
• Light travels to all directions from the source.

Transparent Materials

They are materials that allow all light to pass through them and one can see through them clearly.
Examples: Clear glass, Clear water, air

Uses of transparent materials

• They are used in making:
• Car windscreens
• Spectacles
• Window panes
• Lamps
• Glass walls

Translucent Materials

They are materials that allow only little light to pass through them.
Examples:

• Frosted glass
• Tracing paper
• Oiled or waxed paper

Uses of translucent materials

They are used in making:

• Skylights
• Toilet and bathroom window panes
• Ambulance windows.

Opaque Materials

They are materials that do not allow any light to pass through them.
When light hits an opaque materials a shadow is formed.
Examples:

• Wood
• Stone
• Metals

Reflection of Light

Reflection is the bouncing back of light when Materials that reflect light are called reflectors.
Reflection happens when light hits a smooth shinny surface.

Types of Reflection

• Regular reflection
• Irregular (diffused)

Characteristics of the image in a plane mirror

• The image is upright
• The image is behind the mirror
• The image is the same size as the object
• The image is laterally inverted.

Refraction of Light

It is the process in which light bends or changes direction when it moves from one medium to another. (air to water)

Effects of Refraction                                       

• Objects appear bent or broken
• Objects appear bigger
• Swimming pool appear shallower

Making a Rainbow

A rainbow is formed by the refraction of light. To be formed raindrops and sunshine is required.
The process of splitting light into seven different colours is known as dispersion.
A group of seven colours in the rainbow is known as spectrum

• Food Preservation
  • Reason for Preserving Food
  • Methods of Food Preservation

Food Preservation

It is the process of storing and handling food properly so as to stop or slow down its spoilage.

Reason for Preserving Food

• To reduce food wastage
• To prevent it from being spoilt
• For easy transport
• To make food available when out of season.

Methods of Food Preservation

Food preservation is classified into;

• Traditional methods
• Modern methods

Traditional Methods

They include;

• Smoking- forms a coat
• Drying- reduce moisture
• Salting- reduce moisture
• Use of honey- prevents oxygen
• Use of ash- reduce moisture

Modern Methods

• Canning-killing germs and preventing oxygen
• Refrigeration- low temperature
• Freezing- low temperature

Drying is both traditional modern method of preserving food. It is also the cheapest method of food preservation.

• Soil Erosion
  • Agents of Soil Erosion
  • Factors that Infuence Soil Erosion
  • Types of Soil

Soil Erosion

Soil erosion is the carrying away of the top soil from one place to another.

Agents of Soil Erosion

They are things that carry soil from one place to another. They include;

• Water
• wind

Factors that Influence Soil Erosion

1. Slope of land
2. Type of soil
3. Vegetation cover
4. Amount of rainfall
5. Human activities

Types of Soil Erosion

1. Splash erosion
2. Sheet erosion
3. Rill erosion
4. Gulley erosion

Splash Erosion

It occurs when raindrops fall on bare loose soil.
It can be controlled by;

• Planting cover crops
• mulching

Sheet Erosion

It occurs when water or wind carries away thin uniform layers of the topsoil.
It is not easily noticed
It occurs on gentle slopes.
Best controlled by;

• Planting cover crops
• Planting trees
• Landslides are caused by sheet erosion

Rill Erosion

It occurs when water flows down a slope and make small shallow channels. The channels are known as rills. it is common on gentle sloping areas.
It can be controlled by;

• Terracing
• Contour farming
• Strip cropping

Gulley Erosion

It occurs when water make deep channels , they are known as gulleys.
Gulley erosion leads to the formation of V-shaped or U-shaped channels.
It is common on bare hill slopes.
It can be controlled by;

• Gabions
• Porous dams
• Check dams

• Waterborne Diseases
  • Cholera
  • Typhoid
  • Bilharzia

Waterborne Diseases

They are diseases that are spread through contaminated water. They include:

1. Cholera
2. Typhoid
3. Bilharzia.

Cholera

It is caused by bacteria. it can cause death within 24 hours if not treated. It causes death through dehydration.

Signs and Symptoms

• Violent diarrhoea (rice water).
• Vomiting.
• Severe abdominal pains
• Wrinkled skin due to dehydration.
• Sunken eyeballs

Typhoid

It mainly affects the intestines. It is also known as typhoid fever.

Signs and Symptoms

• Pain in the joints and muscles
• High fever
• Abdominal pains
• Skin rash

Bilharzia

It is caused by bilharzia worms or blood flukes. It is carried by water snails.

The disease mainly affect the bladder and intestines
Bilharzia worms enter the body through the skin.

Signs and Symptoms

• Blood in urine and stool
• Coughing may occur
• Abdominal pain
• Swimmers itch
• Fever

• Animal Feeds
  • Pastures
  • Fodder
  • Conserved Feeds
• Methods of Grazing
  • Rotational Grazing
  • Zero Grazing
  • Herding

Animal Feeds

They are classified into:

• Pastures
• Fodder
• Conserved feeds
• Commercial feeds

Pasture

They are grasses and legumes that animals feed on directly.

They are classified into;
Pure stand ; only consist of either grass or legumes only
Mixed stand ; consists of both grass and legumes

Grass

Examples of grass include;

• Kikuyu grass
• Star grass
• Giant sataria
• Rhodes grass

Legumes

There are 4 main legumes used as pasture, they include;

• Clover
• Lucerne
• Glycine
• Desmodium.

Fodder

They are crops that are hervestered or cut then given to the animals. examples;

• Napier grass
• Guatemala grass
• Potato vines
• Maize stalks
• Kales
• Sugar beet

Conserved Feeds

They are animal feeds that are preserved in a special way to be used in future.
They are divided into two;

1. Hay
2. sillage

Hay

• It is cut and preserved by drying
• It is stored in bales

Silage

• It is harvested when it is about to flower. It is preserved by fermentation.
• It is stored when still green or in the succulent state.
• It is stored in silos
• The molasses is added to speed up fermentation.

Methods of Grazing

• Rotational grazing
• Zero grazing
• Herding

Rotational Grazing

They include:

• Tethering
• Paddocking
• Strip grazing

Tethering

The animal is tied to a peg or post using a rope
The rope allows the animal to graze within a restricted area.
It is practised were few animals are kept

Paddocking

The land is divided into small areas known as paddocks using a permanent fence
A watering point is usually provided in each paddock.

Strip grazing

The animals are enclosed in a small portion of the pasture using a temporary fence.
An electric fence is usually used.

Zero Grazing

It is also known as stall feeding
The animals are confined in a permanent structure (shed)
The shed should have feeding area, watering area, sleeping area and milking area.

Herding

It is a type of grazing where animals are allowed to graze
freely on large areas of land.

Venus is the brightest and the hottest
Mercury takes the shortest time to go round the sun
Mars is known as the red planet
Jupiter is the largest planet
Saturn has visible rings around it.
Asteroids are found in between mars and Jupiter
Planets ;smallest to largest

Rotation

it is the process in which the Earth spins on its own axis
The Earth rotates on its own axis
The earth takes 24 hours to make a complete rotation.
The rotation cause day and night

Revolution

It is the process in which the Earth moves around the sun.
The path that is followed by the Earth as it goes around the
sun is called orbit
The Earth takes 365 ¼ days to make one complete revolution.

• Parts of a Plant
  • Flower
  • Male parts
  • Female Parts
• Pollination
  • Types of Pollination
• Germination
  • Types of Germination
  • Parts of a Seed

Parts of a Plant

Main parts of a plant are;

• Roots
• Stem
• Leaves

Flower

The main reproductive part of a plant is a flower.

Parts of a flower include;

• Male part
• Female part

Functions of Different Parts;

Male Parts

• Anthers; produce pollen grain(male cells)
• Filament; it supports the anthers

Female Parts

• Stigma; receives the pollen grains
• Style; holds the stigma
  Allow the development of pollen tube
• Ovary; holds the ovules
  Develops in a fruit
• Ovule; female cell
  Develops into seeds

Pollination

It is the transfer of pollen grains from the anthers to the
stigma of the same kind

Agents of pollination include;

• Wind
• Insects
• water

Types of Pollination

There are two types;

• Self pollination-it is the transfer of pollen grains from the anthers to the stigma of the same plant.
• Cross pollination-it is the transfer of pollen grains from the anthers to the stigma in different plants of the same type.

Characteristics of insect pollinated flowers

• They have nectar
• Brightly coloured
• Have big petals
• Sticky stigma
• Small amount of pollen grains

Characteristics of wind pollinated flowers

• Small in size
• Dull in colour
• Powderly pollen grains
• Produce large amount of pollen grains
• Loosely attached filaments

Germination

It is the change of the seed into a seedling

Conditions necessary for germination

• Air (oxygen)
• Moisture(water)
• Warmth(temperature)

Types of Germination

Epigeal germination; the seed comes out of the soil during germination e.g. Beans
Hypogeal germination; the seed remains in the soil during germination e.g. maize

Parts of a Seed

• Testa
• Helum
• Micropyle
• Cotyledon
• Radical
• Plumule.

• Immunisation Schedule
  • Immunizable Diseases
• Hiv and Aids Testing
  • Effects of HIV/AIDS to the Country
  • Effects to the Family
  • Effects of HIV to the Individual

Immunisation Schedule

They are diseases that a child is immunised against before
they are 5 years.
Most of the diseases are dangerous if they infect a young child.

Immunizable Diseases

They are diseases that one can be immunised against;

• Typhoid
• Yellow fever
• Meningitis
• Tuberculosis
• Measles
• Tetanus

Hiv and Aids Testing

Reasons of getting tested

• To overcome fear
• To stop the spread of HIV
• To plan your future
• To start medication early
• To decide on marriage partner
• To plan for your family

Pre-test counselling; it is the testing one receives in the VCT centre before being tested.
Post-test counselling; it is the testing one receives in the VCT after being tested

Effects of HIV/AIDS to the Country

• Reduced agricultural production
• Poor economy
• Death of skilled people
• A lot of money is spent on treatment
• Congestion in the hospitals

Effects to the Family

• Sadness in the family
• Family income is spent on treatment
• Children may become orphans
• Children may drop out of school to take care of the sick parents
• The family may feel discriminated.

Effects of HIV to the Individual

• Poor health
• Poor performance
• Spending of a lot of money
• Feeling stigmatized

• Male Reproductive System
• Female Reproductive System
• Physical Changes
• Emotional Changes

Male Reproductive System

Parts of the male reproductive system include

• Penis
• Testis
• Urethra
• Sperm duct
• Glands

Female Reproductive System

Parts of the female reproductive include

• Ovary
• Oviduct
• Uterus
• Cervix
• Vagina

Functions

• Ovary-produce the ova after every 28 days
• Oviduct-where fertilisation takes place
• Uterus-where the foetus develop till maturity
• Cervix-a ring of muscle that holds the foetus to maturity
• Testis-they produce sperms
• Urethra-allow passage of sperm and urine in men

Physical Changes

In both boys and girls

• Increase in height and weight
• Hair appear in the armpit and the pubic area
• Pimples may appear on the face

In boys only

• The voice breaks
• They experience wet dreams
• The chest broadens

Girls only

• The breasts enlarge
• Voice become smooth
• They experience menstrual flow
• Hips broaden

Emotional Changes

They mainly affect the feelings, they include;

• Feeling shy
• Embarrassment of,
• Their height
• Enlarged breasts
• Wet dreams
• Menstrual flow
• Get moody very fast