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SCIENCE FORM 4CHAPTER 2: BODY COORDINATION

Body coordination is the adjustment of the body in response to whatever stimulus received by some parts of the body.There are two types of body coordination : nervous coordination and hormonal coordination.The central nervous system is the control centre of the body. This system consists of the brain and the spinal cord.The peripheral nervous system consists of the autonomic nervous system and the somatic nervous system.

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SCIENCE FORM 4The neurone is a basic unit of the nervous system. There are three types of neurone:

Sensory neurone- carries impulses from the receptor or sensory organ to the central nervous system.

relay neurone- connects sensory neurone with motor neurone.

motor neurone- carries impulses from the central nervous system to effectors, like muscles or glands.

Sensory neurone Relay neurone Motor neurone

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SCIENCE FORM 4Comparision between sensory neurone, relay neurone and

motor neurone.Characteristic Sensory neurone Relay neurone Motor neurone

Position of cell body

In the middle of neurone

At the centre of neurone

At the end of neurone

Length of axon Short Changes Long

Movement of impulse

From the sensory organ or the receptor to the central nervous system

From the sensory neurone to the motor neurone in the central nervous system

From the relay neurone going out from the central nervous system to the muscle or effectors

Function Carries impulses from sensory organ or receptor to central nervous system

Transmit impulses from sensory neurone to motor neurone

Transmits impulses from central nervous system to effector

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SCIENCE FORM 4The human brain consists of three parts:

cerebrum- controls the functions of sensory organs and voluntary actions.

cerebellum – control body balance and coordinates body movements.

medulla oblongata- control involuntary actions.

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SCIENCE FORM 4

Mitosis Differences Meiosis

Somatic cells Place occurs Testes and ovaries

One Number of cell division

Two

Two Number of daughter cells

Four

Same as parents,diploid (2n)

Chromosomal number of

daughter cells

Half the number of chromosomes of the parent (n)

Genetically identical to the parent cell

Genetic content Different from the parent cell and from one another.

CHAPTER 3: HEREDITY AND VARIATIONComparision between meiosis and mitosis

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SCIENCE FORM 4Comparison between continuous and discontinuous variation

Continuous variation

Differences Discontinuous variation

Difference is not obvious

Differences in characteristic

Difference is obvious and definite

Height, body weight, skin colour

Examples of variation

Blood group, type of fingerprint, ability to roll the tongue

Normal distribution

Shape of graph Discrete distribution

Genetic and environmental factors

Factors that cause variation

Genetic factor

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SCIENCE FORM 4CHAPTER 4: MATTER

Pure substances have a specific melting point (freezing point) and boiling point.Any impurity added to pure substance will raise the boiling or lower the freezing point of that substance.For example, water that is with salt will boil at a temperature higher than 100 C and will freeze at a temperature lower than 0C

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SCIENCE FORM 4CHAPTER 5: ENERGY AND CHEMICAL CHANGES

Exothermic reaction is a reaction that releases heat energy to the surroundings.Heat energy released from reactant to the surroundings causes the surrounding temperature to rise.Endothermic reaction is a reaction that absorbs heat energy from the surroundings.Heat energy absorbed by the reactant from the surroundings lowers the surrounding temperature.

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SCIENCE FORM 4CHAPTER 6: RADIOACTIVE SUBSTANCES

TheThe characteristics of radioactive radiation

RadioactiveradiationAlpha rays

Nuclei of heliumConsists of positively

charged (+) particles.

The penetrating power is low,

can be blocked by a sheet of

paper.

Beta raysConsist of high speed electrons, which are

negatively charged (-)The penetrating power is

higher, can be blocked by a thin sheet of aluminium

Gamma raysNeutral (in term

of electrical charges)

Consists of high power

electromagnetic waves.

The penetrating power is very

high, can only be blocked by a

thick lead or a thick concrete

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SCIENCE FORM 4CHAPTER 7: LIGHT,COLOUR AND SIGHT

Primary colours are colours which cannot be obtained from mixing other colours.There are three primary colour, namely red, blue and green.Secondary colours are colour produced by adding primary colours.There are three secondary colours, namely yellow, magenta and cyan.Addition of primary colours and secondary colours can produce white light.

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SCIENCE FORM 4CHAPTER 8: CHEMICALS IN INDUSTRY

An alloy is a mixture of two or more metals (like bronze and brass) or a metal with a small amount of non-metal (like steel)Examples of alloy are steel, pewter, bronze, brass and duralumin.Alloying can:

Increase the hardness of metalsPrevent corrosionImprove the appearance of metals

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SCIENCE FORM 5CHAPTER 1: MICROORGANISMS

Vector is an agent that carries diseases.Houseflies and mosquitoes are two main vectors that transfer pathogen to humans.Diseases like cholera and hepatitis A can be prevented if the population of houseflies is controlled.Dengue fever and malaria can be prevented is mosquito reproduction is prevented.Knowledge on the life cycle and behaviour of vectors can help us to eliminate them.

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SCIENCE FORM 5The lifeThe life cycle of a mosquito

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SCIENCE FORM 5The life cycle of a housefly

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SCIENCE FORM 5CHAPTER 2: NUTRITION AND FOOD

PRODUCTIONThe quantity of energy needed by an individual depends on the factors:

GenderAgeBody sizeWeatherPhysical activityHealth condition

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SCIENCE FORM 5Gender

Males need more energy than females because they are more active

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SCIENCE FORM 5Age

Young people need more energy than old people because they are more active

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SCIENCE FORM 5Body size

A bigger body needs more energy because the metabolic rate of those with bigger bodies are higher.

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SCIENCE FORM 5Weather

People in cold places need more energy to maintain their body temperature.

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SCIENCE FORM 5Physical activities

Active people or those doing laborious jobs need more energy.

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SCIENCE FORM 5Health condition

Sick people need more nutritious food to fight diseases as compared to healthy people.

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SCIENCE FORM 5CHAPTER 4: CARBON COMPOUND

Organic carbon compounds originate from living things. Examples: sugar, starch and cellulose.Inorganic carbon compounds originate from non living things. Examples: carbon dioxide and calcium carbonate.Hydrocarbon compounds are compound that are made up of only hydrogen and carbon elements.Petroleum, natural gas and coal are examples of natural resources of hydrocarbon

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SCIENCE FORM 5CHAPTER 5: MOTION

Comparision between speed, velocity and acceleration

SPEED VELOCITY ACCELERATION

Meaning Distance travelled within one unit of time

Rate of change in distance in a specific direction

Rate of change in velocity of a moving object

Formula Speed=distance

time

Velocity:

Displacement

time

Acceleration:

Final velocity-initial velocity

time

Unit Metre per second

Or ms¯¹

Metre per second or ms¯¹

Metre per second per second or ms¯²

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SCIENCE FORM 5Application of Bernoulli’s principle in aircraft

flight.Wings of aircraft have an aerofoil shape.The flow of air is faster at the top than that at the bottom of the aerofoil.According to Bernoulli principle, the top part of an aerofoil will have low pressure where the air flow is faster. At the bottom of the aerofoil where air flow is slower, the pressure is higher and will produces a lift force that pushes the wing upwards.

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SCIENCE FORM 5CHAPTER 6: FOOD TECHNOLOGY AND

PRODUCTIONAmong the effords conducted to increase the quality and quantity of food production include:

Usage of quality breedsUsage of modern technologyEducation and guidance to farmersResearch and developmentOptimum usage of land and water catchment

areas.Efficient management of land.

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SCIENCE FORM 5CHAPTER 7: SYNTHETIC MATERIALS IN

INDUSTRY

The properties of thermoplastics

Good electrical insulator

Low melting point causes it to soften easily

when hot and return to its original shape once cooled

Can be stretched and burned easily

The ability to mould repeatedly enables thermoplastic to be recycled

Colourless and transparent

Most thermoplastics materials dissolve in organic solvents

Resistant to most chemical substances such as acid and alkali

Did not have cross linkages between molecule

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SCIENCE FORM 5The properties of thermoset

The properties of thermoset

High melting point causes thermoset harden

when cooled and is unableto melt once again although heated at high temperature

Does not bend or burn easily

Can be moulded only once and thus, cannot be recycled

Do not dissolved in any organic solvent

Resistant to most chemical substances such as acid and alkali

Good electrical insulator

Harder, more shock and heat resistant compared

to thermoplastic

Have cross linkage between molecules

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SCIENCE FORM 5CHAPTER 8: ELECTRONICS AND COMMUNICATIONS

TECHNOLOGY (ICT)The properties of waves and their description

Property of waves Description

Wavelength The distance between two successive of waves

Wave frequency The number of complete waves generated in one second

Wave amplitude The maximum displacement of a wave from its original position (or equilibrium position)

Wave velocity The distance travelled by a wave in one second

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SCIENCE FORM 5

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SCIENCE FORM 5

THE END….GOOD LUCK !!!!