SCIENCE FORM 4
CHAPTER 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 4
The 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.
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Sensory neurone
Relay neurone
Motor neurone
SCIENCE FORM 4
Comparision between sensory neurone, relay neurone and motor
neurone.
Characteristic
Relay neurone
Motor neurone
Position of cell In the middle of
body
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
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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Function
Sensory neurone
SCIENCE FORM 4
The 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
CHAPTER 3: HEREDITY AND VARIATION
Comparision between meiosis and mitosis
Mitosis
Somatic cells
Differences
Place occurs
Meiosis
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)
Genetic content
Different from the
parent cell and from
one another.
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Genetically
identical to
the parent cell
SCIENCE FORM 4
Comparison between continuous and discontinuous variation
Continuous
variation
Differences
Discontinuous
variation
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
Factors that
cause variation
Genetic factor
Difference is not
obvious
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Genetic and
environmental
factors
SCIENCE FORM 4
CHAPTER 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
0°C
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SCIENCE FORM 4
CHAPTER 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 4
CHAPTER 6: RADIOACTIVE SUBSTANCES
The characteristics of radioactive radiation
Alpha rays
Nuclei of helium
Consists of
positively
charged (+)
particles.
The penetrating
power is low, can
be blocked by a
sheet of paper.
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The
Radioactive
radiation
Beta rays
Consist of high speed
electrons, which are
negatively charged (-)
The penetrating power is
higher, can be blocked by a
thin sheet of aluminium
Gamma rays
Neutral (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
SCIENCE FORM 4
CHAPTER 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 4
CHAPTER 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 metals
Prevent corrosion
Improve the appearance of metals
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SCIENCE FORM 5
CHAPTER 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 5
The lifeThe
cycle
lifeof a mosquito
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The life cycle of a housefly
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SCIENCE FORM 5
CHAPTER 2: NUTRITION AND FOOD PRODUCTION
The quantity of energy needed by an individual depends on the
factors:
Gender
Age
Body size
Weather
Physical activity
Health condition
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SCIENCE FORM 5
Gender
Males need more energy than females because they are more
active
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SCIENCE FORM 5
Age
Young people need more energy than old people because they
are more active
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SCIENCE FORM 5
Body size
A bigger body needs more energy because the metabolic rate
of those with bigger bodies are higher.
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Weather
People in cold places need more energy to maintain
their body temperature.
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Physical activities
Active people or those doing laborious jobs need more
energy.
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Health condition
Sick people need more nutritious food to fight diseases as
compared to healthy people.
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SCIENCE FORM 5
CHAPTER 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 5
CHAPTER 5: MOTION
Comparision between speed, velocity and acceleration
SPEED
VELOCITY
ACCELERATION
Meaning Distance travelled
within one unit of
time
Rate of change
Rate of change in
in distance in a
velocity of a moving
specific direction object
Formula Speed=distance
time
Velocity:
Displacement
time
Acceleration:
Final velocity-initial
velocity
time
Metre per
second or ms¯¹
Metre per second per
second or ms¯²
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Unit
Metre per second
Or ms¯¹
SCIENCE FORM 5
Application 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 5
CHAPTER 6: FOOD TECHNOLOGY AND PRODUCTION
Among the effords conducted to increase the quality and
quantity of food production include:
Usage of quality breeds
Usage of modern technology
Education and guidance to farmers
Research and development
Optimum usage of land and water catchment areas.
Efficient management of land.
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SCIENCE FORM 5
CHAPTER 7: SYNTHETIC MATERIALS IN INDUSTRY
Low melting point causes
it to soften easily
when hot and return to
its original shape once cooled
Did not have cross linkages
between molecule
Resistant to most chemical
substances such as acid and alkali
The properties
of thermoplastics
Can be stretched and burned easily
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The ability to mould repeatedly
enables thermoplastic to be recycled
Good electrical insulator
Most thermoplastics materials
dissolve in organic solvents
Colourless and transparent
SCIENCE FORM 5
The properties of thermoset
High melting point causes
thermoset harden
when cooled and is unable
to melt once again although
heated at high temperature
Does not bend or burn easily
Can be moulded only once
and thus, cannot be recycled
Harder, more shock and heat
resistant compared
to thermoplastic
Have cross linkage
between molecules
The properties
of thermoset
Good electrical insulator
Resistant to most chemical
substances such as acid and alkali
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Do not dissolved in any organic solvent
SCIENCE FORM 5
CHAPTER 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)
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Wave velocity
The distance travelled by a wave in one
second
SCIENCE FORM 5
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THE END….
GOOD LUCK !!!!
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