Grade 7 CBC Complete Integrated Science Notes.

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1 SCIENTIFIC INVESTIGATIONS.
Introduction to Integrated Science.
What is integrated science?
 To integrate is to bring together or to combine parts of something into a whole.
 Integrated science means the study of five basic natural sciences which are Physics,
Chemistry, Biology, Earth Science and Astronomy and how they overlap.
Knowledge and Skills gained from Integrated Science.

 Integrated Science provides learners with an opportunity to measure their ability in
science.
 It prepares a learner to study science at higher levels and even choose it as a career.
 It provides learners with the required skills, knowledge and attitudes necessary for
specialization in Applied Sciences as well as Pure sciences (Physics, chemistry and
Biology), and Careers and technology studies (CTS) offered in the Science Technology
Engineering and Mathematics (STEM) pathway at the senior school level.
 The following tables shows the STEM pathway.
Track Core subjects Optional subjects
Pure  Community Service The learner should select a minimum
sciences Learning. of three from the following subjects:
 Physical Education.  Mathematics.
 Information  Physics.
Communication  Chemistry.
Technology (ICT)  Biology.
Applied  Community Service The learner should select one of the
sciences Learning. following subjects:
 Physical Education.  Agriculture.
 Information  Computer science.
Communication  Food and Nutrition.
Technology (ICT)  Home Management.
Technical  Community Service The learner should select one of the
and Learning. following subjects:
engineering  Physical Education.  Agricultural technology.
 Information  Geoscience technology.
Communication  Marine and fisheries
Technology (ICT) technology.
 Mathematics.  Aviation technology.
 Chemistry or Biological  Wood technology.
Sciences.  Electrical technology.
 Metal technology.
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 Physics or Biology or  Power mechanics.
Physical Science.  Clothing technology.
 Construction technology.
 Media technology.
 Electronics technology.
 Manufacturing technology.
 Mechatronics.
Career and  Community Service The learner should select one of the
technology Learning. following subjects:
studies  Physical Education.  Garment making and interior
(CTS)  Information design.
Communication  Leather work.
Technology (ICT)  Culinary arts.
 Hair dressing and beauty
therapy.
 Plumbing and ceramics.
 Welding and fabrication.
 Tourism and travel.
 Air conditioning and
refrigeration.
 Exterior design and
landscaping.
 Building construction.
 Photography.
 Graphic designing and
animation.
 Food and beverage.
 Motor vehicle mechanics.
 Carpentry and joinery.
 Fire fighting.
 Metal works.
 Electricity.
 Land surveying.
 Science laboratory
technology.
 Electronics.
 Printing technology.
 Crop production.

Importance of Integrated Science in Daily Life.
Scientific knowledge has allowed us to develop new technologies, solve problems and make
informed decisions. Some uses of science in different fields are as follows:
 Transportation.
 Science has made the world a global village for example, bicycles, cars and
aircrafts are invented of science. Therefore, people and goods can be transported
easily and faster.
 Medicine.
 Most equipment used in medical field are scientific inventions. Examples include
stretchers, electrocardiogram (ECG) machines and magnetic resonance imaging
(MRI) machines etc.
 Agriculture.
 In agriculture field science has major contributions such as the machines like
tractors, drip irrigation system, sprinklers irrigation system among others.
 Communication.
 Mobile phones and computers are scientific inventions used majorly in
communication.
 Construction.
 Construction of building is based on science and technology. Machines used in
construction works such as motor graders, bulldozers are scientific inventions.
Laboratory Safety
 The school laboratory designs should be in such a way that learners can perform
experiments safely.
 Learners must also be careful when handling materials and when using equipment in the
laboratory.
 The table below shows common hazards and the accidents they can cause in the
laboratory.
Hazard Accident caused.
Acids and bases (chemicals)  These can irritate or burn the eyes and the skin.
 They can also cause respiratory complications.
Corrosives.  These can cause severe burns on contact.
Electrical hazards (heating  Electricity can cause electric shock, burns, fires
apparatus) and even explosions.
Glass apparatus  These can cause cuts and bruises.

Common Hazards and their symbols in the laboratory.
 Besides the laboratory acting as a store for chemicals and apparatus, many experiments
are done in the laboratory. Hence there are many hazard symbols in the laboratory to help
learners take necessary precautions against dangers and hazards.
 The following are hazard symbols, their meaning and interpretations.
Hazard symbol Meaning Interpretation
Corrosive  The substance can
destroy living tissues
and equipment on
contact.
Caution! Do not breathe in
vapour; avoid contact with
skin and eyes.
Oxidizer  The substance can

ignite flammable and
combustible materials
or worsen existing
fires thus make
firefighting more
difficult.
Caution! Keep away from
such flammable and
combustible materials.
Poisonous  The substance is
hazardous when
inhaled, swallowed or
exposed to the skin. It
may even lead to
death.
Caution! Avoid contact
with the human body and
immediately consult a
physician in case of contact.
Radioactive  The substance has
measurable
radioactivity.
Caution! Avoid exposure to

the substance.

Flammable  The substance can
easily catch fire.
Caution! Keep away from

open flames, sources of heat
and sparks.
Toxic  The substance is

toxic, will
contaminate the
environment and
affects aquatic
animals.
with human body and water
bodies. Immediately consult
a doctor in case of contact.
Harmful or irritating.  This substance can
cause harm or
irritation to human
beings.
with the human body and
immediately consult a
doctor in case of contact.
Carcinogenic  This substance is
capable of causing
cancer.
Caution! Avoid exposure to
the substance.
Common Accidents in the Laboratory and Related First Aid measures.

The following are the causes of common laboratory accidents.
 Cuts are caused by broken glass apparatus (for example test tubes or glass tunings), tools
(for example dissecting instruments or cutters) or sharp edges.

 Carelessness in handling hot objects for example tripod stands, glassware, metal rods or
plates), hot liquids, Bunsen burner flame or lighted matches.
 Learners’ mischievous behaviour of pouring chemicals to others that result into chemical
spillage.
 Learner’s unintentionally rubbing their eyes with hands contaminated with chemicals.
 Accidental ignition of flammable liquids.
 Drinking liquids or inhaling fumes accidentally.
 The effects of common laboratory accidents include burns and scalds, cuts and ingestion
of harmful substances.
 In case of an accident, proceed using the PIA rule where:
 P: PROTECT- move the casuality to a safe place.
 I: INFORM-report to the appropriate authority.
 A: ASSIST-give the necessary help.
Keep calm.
Keep the casuality warm.
Do not move the casuality if you are unaware of the seriousness of the situation.
 All laboratories should have a first aid kit. The first aid kit should contain the
following:
 An instruction manual giving general guidance.
 Individually wrapped sterile adhesive dressings in a variety of sizes.
 Sterile eye pads with bandages for attachment.
 Triangular bandages.
 Safety pins.
 A bottle that contains eye drops.
 A First Aid manual.
 Scissors.
 Gloves.
 Antiseptic.
 The Table below shows common laboratory accidents and related first aid
measures.
Common accident Meaning First Aid.
Cuts. Sharp or pointed - Wash the wound using clean water.
objects penetrate the - Disinfect the wound.
skin causing cuts. Cuts - Apply an antiseptic solution to the
result in bleeding. wound.
- Place a dressing and a bandage to hold it
in place.
- Go to a health centre in case the cut
needs stitches.

Burns and Scalds. Burns are soft tissue - Run the burnt area under cold tap water
injuries caused by with low pressure for 10-15 minutes.
chemical hazards, - Study the size, depth and location of the
electrical hazards or burnt areas. If necessary, proceed to a
radiation. health centre.
Scalds are soft tissue - Cover the burn with a loose gauze
injuries caused by hot dressing or a clean piece of cloth. Do not
liquid or steam. puncture blisters.
Note;
 In case of chemical burns, remove any
clothing contaminated by the chemical,
as long as it is not stuck to the skin. Do
not apply any lotion or any other remedy
to the burnt area.
 In case of electrical burns, ensure the
following
- Before starting First Aid, stop the flow
of electricity.
- The rescuer must be on a rubber or
wooden surface.
- Remove the injured person from the
source of electricity using a plastic or
wooden object, as these do not conduct
electricity.
Ingestion of Harmful substances If the victim is unconscious:

harmful can enter the body  Ask for urgent medical assistance.
substances through the mouth by  Put the casuality in recovery position.
swallowing.  Loosen the clothing and wrap the victim
in a warm blanket.
 Do not induce vomit. If the victim
vomits, clear up the respiratory tract
(cover your fingers) with fabric to clean
the victim’s mouth).
 Do not administer anything orally to an
unconscious victim.
 Do not try to neutralize the toxic
product.
If the victim is conscious and the toxic
substance is corrosive;
 Make the victim drink plenty of water.
 Do not induce vomit.
 Take the victim to a health centre.
Safety measures and regulations in the laboratory.

When working in the laboratory, you must observe the following safety rules:
 Work carefully as carelessness can cause accidents as well as inaccurate results.
 Wear gloves, laboratory aprons and safety glasses.
 Never eat or drink in the laboratory.
 Tie back loose hair, roll back and secure open sleeves and neckties and make sure you
wear shoes that fully cover your feet.
 Do not carry out laboratory experiments at home or in the dormitories unless directed to
do so by your class teacher.
 Carefully read chemical labels and understand the hazard symbol on them.
 Listen carefully to your teacher’s instructions on when and how to use safety equipment
such as glasses, protective aprons, fire extinguishers and fire blankets.
 Make sure you know where the nearest fire alarm is in your school laboratory.
 Do not begin an experiment until the teacher instructs you to do so.
 Do not touch substances unless the teacher instructs you to do so. What looks harmless
may be dangerous.
 Wash your hands with soap and running water after handling chemical substances. Some
chemical substances are poisonous.
 Heat materials in suitable containers only, such as Pyrex glass container that can resist
breakage.
 Always keep the open end of the test tube pointed away from the learners and yourself
when heating chemicals because the fumes produced may be harmful.
 Pick up hot objects carefully using tongs or insulated materials.
 Make sure that you turn off the heat source when not in use to conserve energy.
 Always unplug electric cords by pulling out the plug and not the cord.
 Check that there are no flammable substances near the burner. Flammable substances will
cause fire if exposed to a flame.
 After each experiment, tidy up your working area, clean all equipment and put them in
their respective storage areas.
 Report any accidents, broken equipment and damaged facilities to your teacher. In this
way, you will be taking responsibility for your safety and for those who use the
laboratory after you.
 If a chemical gets into your eyes, wash it out with running water for about 12 minutes and
then visit a health centre or hospital for further medical attention.
 If you inhale poisonous gases or vapour, move outside the laboratory for fresh air.
Immediately seek medical assistance.

 In case of electric shock, immediately cut off the electric power source using an insulated
object.
 In case of a fire outbreak, use sand, fire blankets and fire extinguishers to put out the fire.
Basic Science Skills.

 Science involves processes that are part of a scientific method.
 Scientists approach problems in various ways which have several processes that are
common to them. These commonly used process are called science process skills.
a.) Manipulative skills and abilities.
 These include skills in handling materials and apparatus in a scientific investigation.
 They also involve the ability to follow instructions and make accurate observations.
Examples.
 Using and handling scientific apparatus.
 Cleaning and maintaining scientific apparatus properly and
safely.
 Handling specimens properly and safely.
 Mixing primary colours to create more colours.
b.) Observation skills.
 This is the most common basic skill in science. Scientists make observations by using the
five senses. Good observation skills are helpful in learning other science process skills.
Example.
 Making observations using the sense of touch.
 Creating observation about a coin using the five senses.
c.) Classification skills.

 After observing, it is important to identify he similarities and differences and to group
objects.
Examples.
- Using a magnet to classify objects as either magnetic or nonmagnetic.
- Using a balance and sorting objects according to mass.
d.) Measuring skills.

 Measuring is very important in collecting, comparing and interpreting data.
 It helps us to classify and communicate with others.
Examples.
 Finding the mass of different liquids that have the same volume.
 Using technology to find the speed of a vehicle.
 Measuring the distance that a person travels.

e.) Communication skills.
 Important so that it becomes possible to share our experiences.
 One can do this by using graphs, diagrams, maps and spoken word.
Examples.
 Creating a line graph showing the relationship between speed and time.
 Discussing possible errors with other classmates.
f.) Predicting skills.

 A prediction is an educated guess based on good observation and making a conclusion
about an observed event or prior knowledge.
Examples.
 Predicting what is in a box based on the sense of touch.
 Writing an assumption about the effect of increasing salt on the
buoyancy of an egg.
g.) Conclusion skills.

 A conclusion is an explanation based on observation. It is a link between what you
observe and what you already know.
Example
 Writing a conclusion at the end of each investigation.
 Creating conclusions about observations made about a particular
object, for example, I conclude that it is a solid and not a liquid.’
Packaging Labels on Quantities or Products.
- Packaging labels can be used to pass information about a certain type of products such as
chemicals or food materials.
- A food label is a piece of paper or other materials marked or inscribed and attached to a
food package.
- It contains a variety of information about the nutritive value of the food label.
A food package
label
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 Information that are found on a packaging label.
 Name under which the product sells.
 The manufacture and expiry date.
 Lis of ingredients. Ingredients are things that are combined to make a particular product.
 The quantity of product in the package.
 Any special storage instructions.
 Instructions for use, where necessary.
What is the importance of reading Packaging labels?

 Labels help the consumers to make the right choices on what to buy.
 Labels guide on how to use, store and what to avoid while using the product.
 Labels inform consumers of the products’ name, quantity, ingredients, manufacturing and
expiry date.
 Labels also help people with allergies, especially food allergies, to make informed
choices and know what to avoid.
International System of Units (SI) for basic and derived quantities.
 Products such as sugar, milk, salt are purchased from shops in specific quantities or units
of measure.
Basic and derived units of measurement.
 In 1971 the fourth General Conference on Weights and measures identified seven (7)
quantities as basic quantities. This formed the basis of the International System of Units
abbreviated as SI units from French name Syteme Internationale d’unites.
What are Basic quantities?

 A basic quantity is one whose unit can be defined without referring to other quantities.
 The basic quantities are:
 Length.
 Mass.
 Time.
 Temperature.
 Electric current.
 The table below shows the basic quantity unites and their symbols.
Basic quantity SI unit Symbol
Mass Kilogram kg
Length Metre m
Time Second s
Temperature Kelvin K
Electric current Ampere A

What are Derived Quantities?
 Derived quantities are quantities that are calculated from two or more measurements.
 Derived quantities cannot be measured directly.
 Derived quantities an only be calculated.
Examples of derived quantities are:
 Volume.
 Density.
 Area.
 Volume =length x width x height (m x m x m) or m3 (cubic metres).

 Density = Mass (Kg/m3)
Volume
 Area (square or rectangle) = Length x width (m x m) or m2 (square metres)
Applying the International System of Units (SI)

 Mass.
 Mass is the amount of matter in an object.
 Mass is measured in milligrams (mg), grams (g), kilograms (kg) and tonnes (t).
 Length.
 Length is defined when we measure how long something is.
 It is the distance between two points.
 The units for measurement of length are millimeter (mm), centimeter (cm), Metre (m)
and Kilometres (km)
 Time.
 Time is measured using a digital or analogue clock.
 The basic unit of measuring time is seconds (s).
 Larger units of time are minutes (min) and hours (hr).
 Temperature.
 An instrument that measures temperature is called a thermometer.
 Temperatures is measured in
 Degrees Celsius (0C.)
 Degree Fahrenheit (0F.)
 Kelvin (K)
 The thermometer that measures our body temperature id called a clinical thermomemtre.
The scale used or unit of measurement used is the Celsius scale (0C.)
 A clinical thermometer reads temperatures from 35oC to 42 oC.

 There are other thermometers that measure temperature of other materials such as
laboratory thermometer which has a range from -10 oC to 110 oC.
 Electric current.
 An electric current is the rate of flow of charge through a given point in an electric
circuit.
 The SI unit for measuring the magnitude of an electric current is Amperes (A).
 Area.
 Area is the measure of the size of a surface.
 Two length measurements usually describe area hence presented in square units.
 The basic unit of measuring area is square metres (m2)
 Area can also be expressed in square millimeters (mm2), square centimeters (cm2) and
square kilometres (km2).
 Area of regular shapes
Types of formula Shapes
Triangle
Area =1/2 x base x perpendicular

height
=1/2 bh

Rectangle
Area=length x width
=lw
Trapezium
Area =
Area =1/2 (sum of parallel side) x
perpendicular distance between the
lines
=1/2 (a+b)h
Circle
Area = 𝜋𝑟 2
 Area of irregular shapes.

 Area of an irregular shape can be estimate by first subdiving the shape into small regular
shapes.
 The small regular shapes used can be of 1 cm length.

 The area of the whole shape can be calculated as follows.
 Count the number of whole squares.
 Count the squares which are either half or more than half.
 Add the total number of complete squares to half the total number of the
incomplete squares. For example, in the above picture
Full squares=5
Number of squares that are more than half or half =6 then divide by 2 =3
Approximated are=5+3 = 8 square units.
 Volume.
 It is the amount of space an object occupies.
 Objects can be solids like a brick or liquid like water.
 Apparatus that measure volume of a liquid include;
 Measuring spoon.
 Measuring jug.
 Measuring cylinder.
 The SI unit for measuring volume is cubic metre (m3)
 Volume can also be measured in other units such as;
 Cubic centimetres (cm3)
 Cubic millimetres (mm3)
 Common units for measuring liquid volume include
 Litres.
 Millilitres.
 Density.
 It is the heaviness of a substance in relation to their volume. Therefore, density is mass
per unit volume.
 Mass can be measured in kilograms (kg) while volume is measured in cubic metre (m3)
 Since mass is measured in kg and volume is measured in m3, the SI unit for density is
kg/m3.
 Density can also be expressed in grams per cubic centimetre (g/cm3)

Laboratory apparatus and instruments.
 Apparatus and Instruments for Heating.
 Most common source of heat in the laboratory is the Bunsen burner.
 Other heat sources include portable burners, kerosene stoves, spirit lamps, candles and
electric hot plates.
Spirit lamp Candle Electric hot Portable burner Kerosene stove
plate
Observing A Bunsen burner.

Parts of a Bunsen burner
Functions of the parts of a Bunsen burner.

Part Function
Collar Regulates amount of air entering the Bunsen burner through the air hole.
Air hole Allows air to enter the chimney. (air mixes with the gas making flame hotter and
blue.
Chimney Raises the flame to a suitable height for burning.
(barrel)
Base Supports the Bunsen burner and prevent it from toppling.
Gas hose The flexible hose pipe connects the Bunsen burner and the gas tap.
Flame A hot glowing mass of ignited gas that is generated by something on fire.
Gas inlet Controls the flow of gas to the Bunsen burner.
 Apparatus and Instruments for Measuring Mass.
 Various instruments are used to measure mass.
 Mass can be measured using a beam balance, electronic balance and weighing balance.
Electric balance Beam balance Weighing balance
 Apparatus and Instruments for Temperature.

 Temperature is defined as the hotness or coldness of any object or substance.
 Kelvin (K) is the SI units for temperature.
 Apart from Kelvin, temperature is also measured using the Celsius scale (oC) and
Fahrenheit scale (oF)
 A laboratory thermometer is the instrument used to measure temperature in the
laboratory.
 Apparatus and Instruments for Measuring Length.

 Length of an object in the laboratory is mostly measured using the metre rule, 15 cm
ruler, 30 cm ruler and the tape measure.
Metre rule Tape measure
Part of metre rule.

 Apparatus and Instruments for Measuring Volume.
 In the laboratory various instruments are used to measure volume of liquids.
 Examples of these instruments include:
 Conical flask.
 Syringe.
 Beaker.
 Burette.
 Graduated cylinder.
 Pipette.
 Volumetric flask.
Conical flask Syringe Beaker
Burette Graduated cylinder Pipette
Volumetric flask

 Apparatus and Instruments for Measuring weight.
 Weight is the pull of gravity on a mass of a body.
 The pull of gravity is the force that pulls objects towards the centre of the earth.
 The SI unit of weight is Newton (N)
 A spring balance is commonly used to measure weights of objects in the laboratory.
Spring balance
 Apparatus and Instruments for Measuring time.

 In the laboratory, a clock, wristwatches and stopwatches are commonly used to measure
time.
 The SI units for measuring time is seconds (s).
 Time can also be measures using other dimensions such as minutes and hours.
Clock Wristwatch Stop watch

 Apparatus and Instruments for Magnification.
 Hand lens.
 It is a lens of specified magnification fixed on a frame.
 When a hand lens is moved up (far) and down (close) over a specimen, it enlarges up to
the sharpest image where you can clearly view the specimen and the viewer can observe
particular details.
 Hand lens have a limited magnification of between X5 and X10.
 Microscope.
 A microscope is an instrument used to magnify (enlarge) small objects for clear visibility.
 Plant and animal cells are too small to be viewed with naked eyes, therefore a microscope
is used to view the cells.
Parts of the Microscope.

Functions of different parts of the Microscope.
PART USE/FUNCTION
1 Eyepiece lens  Used to observe specimen under the microscope.
2 Body tube  It holds the eyepiece lens and the objective lens in position
allowing light from the specimen to pass to the observer.
3 Stage  It is where the specimen is placed during examination or
viewing.
4 Arm  It supports the body tube and the lenses.
 It is also used to carry the microscope when moving it from
one place to another.
5 Fine adjustment  Moves the body tube hence bringing the object (specimen)
knob into focus.
6 Coarse  Brings the object further through a long distance.
adjustment
7 Objective lens  It magnifies the object or specimen after the eyepiece lens.
8 Revolving nose  It holds objective lenses in position.
piece
9 Diaphragm  It regulates (controls) the amount of light entering the stage.
10 Condenser  It concentrates light onto the stage from a source.
11 Base  Supports the entire microscope firmly.
12 Stage clips  It holds the specimen on the slide in position during
observation.
Handling of common laboratory apparatus and instruments.

 Handle all glass material carefully. Breakages are dangerous and may result in losing
important materials.
 Place flasks and beakers on a gauze mat or wire gauze when heating over a Bunsen
burner flame.
 When diluting concentrated acids, use thin-walled glassware since the heat evolved by
the procedure often cracks thick glassware.
 Number containers and their corresponding ground glass stoppers to ensure direct
matching when you replace the stopper.
 All chemicals should be well labelled and stored in the right place using proper
containers.

Handling of the Bunsen Burner.
 Always turn off the Bunsen burner after use.
 Always make sure that flammable liquids and combustible materials are not near the
Bunsen burner to avoid the risk of unwanted fires and explosions.
 When lighting the gas, have your strikers ready to avoid excess gas leakage that might
lead to an explosion.
 Once you are done with the Bunsen burner, it is critical to turn off the main gas valve to
avoid leakages.
 The burner should cool completely after use before any further handling.
Handling a light microscope.

 Always use both hands when carrying a light microscope.
 Do not place a light microscope on the edge of a bench or table as it may fall.
 Do not place specimens directly on the stage of a light microscope. Always place them on
a microscope slide and cover them with a cover slip.
 Always use a lens tissue to cleans the lenses. Hard materials are likely to scratch the
lenses.
 Ensure that the low power lens is in position before storing the microscope.
 Always dust the microscope using a soft cloth, for example linen.

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2 MIXTURES, ELEMENTS AND THEIR
ENVIRONMENT
 A mixture is a combination of two or more substances put together resulting to a mass.
 Mixtures are commonly used in daily life such as soil, coffee and air.
 Soil is a mixture of sand, stone, clay, salts and living organisms.
 Air is a mixture of different gases such as oxygen, nitrogen, carbon dioxide, water vapour
and other gases.
 The substances that are combined to form a mixture are called components.
Types of Mixture.
 Homogeneous mixture.
 It appears uniform to the eyes.
 Homogenous mixtures form a uniform composition.
 Example, cement is a homogenous mixture of different solids such as limestone, shells
and chalk among others.
 Other homogeneous mixtures are steel (iron and carbon) and bronze (copper and tin).
 Heterogeneous mixture.
 Heterogeneous mixture is a mixture made up of a non-uniform composition.
 If you take two samples from different parts of the mixture they will not be identical.
 For example, you can differentiate rice (solid) from salt(solid) in the mixture.
 Other heterogeneous mixtures include salt and sand, sand -sugar, salt -gravel mixtures.
In some cases, two or more substances are mixed together to form a special kind of
mixture.
 For example, when you mix salt (solid) and water (liquid), the solid seems to disappear in
the water. This process is called dissolving and it forms a solution.
 When a solid dissolve in a liquid, the liquid is called a solvent and the solid that dissolves
is called a solute.
 A solution is a special type of mixture that is homogenous and so you cannot tell the
difference between the components of a solution.
 Water and sand forms a heterogeneous mixture. One can easily separate the sand from
water.
 Milk (liquid) mixes with water (liquid) completely to form a uniform mixture. Therefore,
this mixture is homogeneous.
 Oil (liquid) mixes with water (liquid) to form a new substance that is not uniform. Both
substances of the mixture can be seen. Therefore, this mixture is heterogeneous.
 A gas-gas mixture is comprised of various gases, for example, the air we breathe is a
combination of oxygen, nitrogen, carbon dioxide, water vapour and other gases.
 The air we breathe is therefore a homogeneous mixture.
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Pure and Impure substances.
 When two pure substances are mixed together they form a mixture.
 A mixture is an impure substance. Therefore, a pure substance is any material that is not a
mixture at all.
 The melting and boiling points of pure and impure substances can be determined.
Melting point of pure substances (Ice).

 It is the temperature at which a solid change into liquid state.
 The melting point of ice is the temperature at which ice is converted from its solid state to
its liquid state.
 Heat from a heat source is used to melt the ice.
 The thermometer helps to note the temperature at which the ice melts.
 After the initial and final readings are taken, it will be observed that once the ice attained
its melting temperature (0oC), the temperature remains the same until all the ice is
converted into liquid state.
 Pure solids have specific melting points. Therefore, it means that ice is a pure substance.
Melting point of Impure substances (Candle wax).

 The melting point of candle wax is the temperature at which the solid materials turns into
liquid (by heating it).
 The melting point of candle wax ranges between 46oC to 68 oC. Therefore, it means that
candle wax is an impure substance.
 Impure substances do not have specific melting points. The presence of impurities affects
the melting point of the substances.
Determining Boiling points of Pure and Impure substances.
Requirements for the

experiment
1. Boiling tube.
2. Thermometer.
3. Heating apparatus.
4. Distilled water.
5. A spatula.
6. Salt and water.

Procedure for the experiment above.
 Put about 10cm3 of distilled water on a boiling tube.
 Close the tube with a stopper that has two holes.
 Pass a thermometer through one hole. Immerse the thermometer bulb into the water.
 Push and ‘L’ shaped tube through the other hole as shown above.
 Heat the apparatus using a small flame.
 Observe the changes in temperature and record your observations.
 Cool the apparatus and remove the stopper.
 Add a spoonful of salt to some water/ stir to dissolve all the salt to form a salty water
solution.
 Repeat the above experiment using a salty water solution in place of pure distilled water.
 Observe changes in temperature, record your observation. What conclusion have you
made.
 At what temperature does water (pure water) boil?
 At what temperature does water with dissolved salt (impure water) boil/
 Compare your observations.
Observations and conclusion & Explanation.

 When distilled water is heated, the temperature of the water rises to about 100oC.
 After this, the temperature remains constant (not changing) for some time. The heat
absorbed changes liquid water into water vapour or steam.
 Pure water has a definite or specific boiling point.
 Salty (impure) water has a range of boiling temperatures above 100oC.
 Impurities cause a rise in temperatures of the boiling point of liquids.
 The greater the impurities in the given solution, the higher the boiling point. Therefore,
we can use the boiling point to determine the purity of a liquid.

Separating Mixtures using different methods.
 Different methods can be used to separate various mixtures.
 Each method is suitable for separating a particular mixture.
a.) Separating mixtures through distillation.
 Requirements.
 A spatula.
 Water.
 A measuring jar.
 A thermometer.
 Common salt.
 Distillation flask
 Condenser.
 Procedure.
 Add about 25cm3 of water to common salt in a distillation flask.
 Shake the mixture carefully to dissolve the salt.
 Set up the apparatus as shown above.
 Heat the mixture until only a little solution remains in the distillation flask.
Questions from the experiment.
1. Through which process does the steam change to liquid in the collecting jar?
2. What is the term used to refer to the water that is collected in the receiving flask?
3. Why is cold water used in the condenser?
4. What is the substance that is left in the boiling tube after the water has evaporated?
 Observation and explanation.

 Simple distillation is successful when the substances in the mixture have different boiling
points such as water and salt.
 The process of distillation is used to get salt and water from the salt-water mixture.
 It involves heating a liquid to form vapour which is then cooled back to the liquid.
 The liquid is obtained by condensing the vapour.

b.) Separating mixtures through filtration.
 Requirements.
 A filter funnel.
 Conical flask.
 Filter paper.
 Water.
 Fine sand particles.
 Procedure.
 Get a filter paper and fold it into a cone.
 Clamp the filter funnel.
 Add sand into a conical flask that contains warm water and stir. Pour the mixture into the
filter funnel and observe. Record your observations.
 Question from the experiment.
1. What observation did you make?
2. What made it possible for the mixture to separate?
3. What is the purpose of the filter paper?
4. What is the name of the liquid that passes through the filter paper?
5. Give the name of the solid particles trapped by the filter paper.
 Observations and explanation
 Filter paper is made up of porous materials that allow liquids to pass through but traps
solid particles during filtration.
 The liquid obtained through the filter paper is called filtrate.
 In the experiment water is the filtrate.
 The filter paper traps solid particles.
 The solid particles trapped is called residue.
 In the experiment sand particles form the residue.
 Sand is insoluble in water and therefore it does not dissolve in water.
c.) Separating mixtures through decantation.

 Requirements.
 Sand particles.
 Water.
 Two beakers.
 Procedure.
 Mix sand and water in a beaker.
 Stir the mixture.
 Leave the mixture to stand for some time until the sand settles at the bottom of the
beaker.
 Carefully, pour the water (liquid) into the other beaker.
 Pour the water in such a manner that the insoluble material (sand) remains in the fisrt
beaker.
 Discuss and record your observations.

 Decantation is the process of separating insoluble solid particles from a liquid, for
example, sand from water.
 After leaving the mixture to stand for some time, the heavy particles of sand settle at the
bottom of the beaker, however the water collected is not clear as it contains some solids
and dirt.
 Decantation can also separate two insoluble liquids such as paraffin and water. The liquid
at the top is poured off in a different container.

d.) Separating mixtures using a magnet.
 Requirements.
 Iron fillings.
 Sand.
 A magnet.
 A bowl.
 Procedure.
 Put the iron fillings in a bowl.
 Add some sand into the bowl.
 Mix the two substances. Describe the mixture.
 Pick the magnet and hold it slightly above the mixture.
 Observe what happens. Record your observations.
1. What do you notice on the surface of the magnet?
2. Why did the magnet pick the iron filings and not the sand?
3. What kind of mixture is a magnet used to separate?
 Observation and Explanation.

 A magnet is used to separate materials attracted to it from those not attracted to it.
 Materials that are attracted to a magnet are called magnetic materials.
 In the experiment above, a magnet attracts iron filings because iron filings are magnetic.
 A magnet does not attract sand as it is nonmagnetic.
 Therefore, the magnet will attract iron filings and separate them from the sand.

e.) Separating mixture using sublimation.
 Requirements.
 Sodium chloride.
 Ammonium chloride.
 Bunsen burner.
 Wire gauze.
 Watch glass.
 Beaker.
 Cold water in a round bottomed flask.
 Procedure.
 Mix sodium chloride (common salt) and ammonium chloride in a glass beaker.
 Cover the beaker with a round-bottomed flask containing cold water.
 Heat the mixture gently and observe what happens. Record your observation.

1. What happens to the mixture when heated?
2. What happens to the surface of the round-bottomed flask?
3. Describe the work of the cold water in the round-bottomed flask.

 Ammonium chloride form white fumes which condense into a white solid on the cooler
surface of the round-bottomed flask and the beaker.
 Sodium chloride (salt) remains in the beaker.
 Sublimation is the direct change of a solid into gas after heating and vapour into solid on
cooling without passing through the liquid state.
 A sublimate is the solid formed when a vapour cools.

f.) Separating mixture through paper Chromatography.
 Requirements.
 Chromatography paper.
 Ink.
 Dyes.
 Colouring agents.
 Water and small plate or bowl with a flat bottom.
 Procedure.
 Draw a line with a pencil on the chromatography paper and place spots of ink or dye on
the pencil line.
 Place the paper uprightly in water (solvent) in the small plate or bowl with flat bottom.
 As the paper is lowered into the solvent, some dye spread on the paper. As the solvent
soaks up the paper, it carries the mixture with it. Different components of the mixture
will move at different rates. This separates the mixture.
 The paper continues to absorb the solvent and the dye spreads further up the paper.
 Compare your observations with those of others, make your conclusion.

 Paper chromatography is a method used to separate Coloured mixtures into their
different parts.
 Paper chromatography is commonly used to separate pigments, dyes and ink.
 Paper chromatography works because ink contains different colours.

g.) Separating mixture through solvent extraction.
 Requirements.
 Piece of plain paper.
 Evaporating dish.
 Mortar and pestle.
 Nuts.
 Procedure.
 Remove outside covering of the grounds.
 Put the nuts in a mortar and grind them using pestle.
 Add propanone and continue grinding for a while.
 Leave the mixture to settle, and then decant the resulting solution into an evaporating
dish.
 Leave the solution in the sun for some time.
 Smear a drop of the remaining solution on a piece of paper.
 Hold the paper towards light and try to look through it.
Discus and record your observation.
1. Explain why the solvent is used in the extraction of oil from nuts.
2. Name other seeds that can be used in place of nuts.

 Solvent extraction is the use of a solvent to dissolve a substance from a mixture to
separate the components of the mixture.
 A solvent can selectively dissolve one or more of the components of a mixture.
 Propanone is a solvent for oil and therefore dissolves oil from the nuts.
 When you put propanone solution in the sun, it quickly evaporates, leaving oil behind.
 Oil seed like corn, sunflower, castor oil and cotton seed can be used in place of nuts.

h.) Separating mixtures through crystallization.
 Requirements.
 Water in a beaker.
 Some salt.
 A heat source.
 Filter paper.
 Glass bowl.
 Procedure.
 Place 50ml water in a
beaker.
 Add salt to it and stir.
 Heat the solution.
 Continue adding salt to
the solution.
 After some time, there will be a point at which no more salt can dissolve in water. This
stage is called saturation point and the solution in known as a saturated solution.
 Therefore, a saturated solution is a solution that can no longer dissolve any more
solute.
 Filter the salt with the help of a filter paper.
 Collect the filtrate in a glass bowl and cool it.
 Record your observation.

 In the experiment, some fine crystals are formed in the bowl.
 Crystallization is a separation method used to separate a solid that has dissolved in a
liquid.
 A solid, for example salt(solute), is dissolved in a liquid, for example water, (solvent)
making a solution.
 The solute is added to the solvent until no more of it dissolved. This makes the solution
saturated.
 As the solvent evaporates from the saturated solution, the solid will come out of the
solution and crystals will start to form.
 Collect the crystals and allow them to dry.

Applications of Separating Mixtures in day to day life.
 We filter dirty water through a piece of cotton cloth to obtain clean water at home.
However, we should always boil such water to kill germs before drinking it.
 We filter tea leaves from the tea before taking the tea.
 Decantation separates the cream from milk. Cream rises to the top of the liquid and is
easily skimmed off.
 Fractional distillation is used in some industries to separate components of mixtures that
have different boiling points. Example is crude oil refining. Crude oil consists of products
with different boiling points. The components of crude oil include:
 Petrol- a fuel for petrol engines.
 Kerosene-used in cooking stoves and lamps.
 Gas oil, lubricating oil, paraffin wax and bitumen or tar used for
tarmacking roads.
 Fractional distillation is used to separate liquid air into its major components of nitrogen
and oxygen.
 Chromatography can be used to find out which flavouring has been added to food.
 Extraction of oil from nuts uses the solvent extraction method.
ACIDS, BASES AND INDICATORS.

 Substances such as lemon, oranges juice and vinegar tastes sour. These is because they
substances contains acids. The chemical nature of these substances is acidic. The acids in
them are natural.
 Some substances taste bitter with their solutions filling soapy when rubbed between the
fingers when touching. These are bases. Their chemical nature is basic.
Plant extracts as acid-base indicators.

 To determine if a substance is acidic or basic we use indicators.
 Indicators change colour when added to a solution contain either a n acidic or basic
substance.
 Turmeric, litmus among others are some of the naturally occurring indicators.
Cautions:
 Do not taste anything unless the teacher asks you to do so.
 So not touch anything unless the teacher asks you to do so.

 Preparing and using Plant Extract indicators.
Requirements.
 Red cabbage.
 A mixer or blender.
 Water.
 Filter paper.
 Common solutions such as lemon, milk, vinegar and bleach.
Procedure.
 Cop some red cabbage and put it in a mixer or blender.
 Add water to it.
 Mix until juice is formed.
 Strain(filter) this mixture in to a beaker. This is the natural indicator.
 Use the prepared red cabbage indicator to test whether the household solutions are acidic
or basic.
 What observations did you make?
 What can you conclude from your observations?
Observation and explanation.
 Acidic substances change colour of the solution from purple to red or pink.
 Neutral substances turn the purple solution to blue.
 Basic substances change the colour of the purple solution to green or yellow.
 Therefore, red cabbage is a natural indicator.
Categories of different household solutions.

 Indicator are substances that change colour when added to acidic or basic solutions.
 Common indicators used in the laboratory are:
 Litmus paper.
 Phenolphthalein.
 Methyl orange.
 Litmus indicator solution turns red in acidic solutions, blue in basic solution and purple in
neutral solutions.
 Colour changes of litmus paper indicators in different solutions.
Red litmus paper Blue litmus paper.
Acidic solution Stays red Turns red
Neutral solution Stays red Stays blue
Basic solution Turns blue Stays blue

 The table below shows colour of Methyl Orange and Phenolphthalein in acidic,
neutral and basic solutions.
Indicator Acidic solution Neutral solution Basic solution
Methyl Orange Red Yellow Yellow
Phenolphthalein Colourless. Colourless Pink
Strength of Acids and Bases.

 pH scale and pH chart.
 pH stands for potential of Hydrogen.
 It is used to find the numeric value of the level of acidity or basicity of a substance.
 It is the most common and trusted way to measure how acidic or basic a substance is.
 The chemical properties of many solution enables them to be divided into three
categories-acidic, basic or neutral solutions.
 The pH scale is used to measure acidity and basicity (alkalinity).
 Solutions with a pH less than 7 are acidic.
 Solutions with a pH of 7 are neutral.
 Solutions with a pH more than 7 are basic (alkaline).
 The pH scale reads from value 0-14.

 Solutions with pH less than 3 are strong acids.
 Solutions with pH values of 3-6 are weak acids.
 Solutions with a pH value of 7 are neutral.
 Solutions with a pH value of more 8-11are weak bases.
 Solutions with a pH value of 11-14 are strong bases.
Hydrochloric lemon vinegar Apple banana milk Water Soap ammonia Drain Alkali/base
acid tomato blood Baking cleaner
soda
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Universal Indicator
 A universal indicator is a mixture of a variety of other indicators.
 A universal indicator can measure the approximate pH of a solution.
 if a universal indicator is added to a solution, it changes to a colour showing the pH of the
solution.

 Acids, Bases and Indicators in Real life.
 Acids and bases are widely used in our daily life such as in agriculture, food preparation
and medicine.
 Uses of acids.
 Vinegar has various household uses such as preservation.
 Citric acid is important part of lemon juice and orange juice; it can also be used in food
preservation.
 Sulphuric acid is widely used in batteries that are used to start the engines of automobiles.
 Industrial production of dyes, paints and fertilizers involve the use of Sulphuric acids and
nitric acid.
 Phosphoric acid is a key ingredient in many soft drinks.
 Uses of bases.
 Manufacturing of soaps and paper involves the use of sodium hydroxide.
 Calcium hydroxide is used to manufacture bleaching powder.
 Magnesium hydroxide is commonly used as a laxative. It also reduces excess acidity in
the human stomach and is therefore, used as an antacid.
 Slaked lime can neutralize any excess acidity in soils.

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3 LIVING THINGS & THEIR ENVIRONMENT
Reproduction in Human beings.
 Menstrual cycle.
 Menstrual cycle consists of natural changes that occur to the body of a female human
being every month in preparation to pregnancy.
 A menstrual cycle lasts between 28-35 days. However, this can vary between female and
from one cycle to the next. The cycle depends on hormones.
 Hormones are chemical messengers in the body.
 They direct the body on what to do and when to do it.
 The menstrual cycle is a process controlled by hormones in the female body.
 These hormones include:
 Oestrogen.
 Progesterone.
 Luteinizing hormone.
 Follicle stimulating hormone.
 The menstrual cycle is divided in to the following phases:
Approximate Event(s)
day(s)
1-5 day  Bleeding from the vagina begins. This is caused by the
loss of the lining of the uterus.
 This is called menstruation or monthly periods
6-14 days  Blood loss stops.
 The lining of the uterus begins to regrow and an ovum
starts to mature in one of the ovaries.
14-25 days  Ovulation occurs.
 The ovum travels through the oviduct towards the uterus.
25-28 days  If the egg becomes fertilized by a sperm and attaches itself
to the uterus wall, the woman becomes pregnant.
 If pregnancy does not occur, the uterus lining begins to
break down again, repeating the cycle.
Challenges related to the Human menstrual cycle.

 Irregular periods.
 This can be determined by finding out how long your menstrual cycles are.
 You can determine your personal menstrual length by counting from day 1 of your period
to day 1 of your next period.
 Day 1 means the first day of the actual flow.
 It is normal to have menstrual cycles that are between 21 and 35 says.
 Your periods are irregular if it tends to come more frequently than every 21 days oe less
often than 35 days.
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 If the circle length falls in the normal range but varies by 7 to 9 days from the cycle to
cycle, that is a sign of an irregular period too.
 For example, if one is 25 days and the next is 33 days, your cycles would be considered
irregular.
 Absent periods.
 In some cases, some females may fail to get periods.
 Others might not get their first period by the age of 16 years.
 Other cases when some females stop getting their regular periods for 6 months or more.
 Irregular bleeding.
 Bleeding very little or no bleeding at all with each menstrual cycle is another challenge
related to the menstrual cycle.
 Light or lack of bleeding can result from being extremely underweight or overweight.
 If you are overweight, losing weight might help to make your periods regular.
 If you are underweight, slow and steady weight gain may help to regulate your menstrual
circle.
 Excessive bleeding is another challenge related to the menstrual cycle.
 Bleeding is considered heavy if it interferes with normal activities.
 However, though common, you should see a doctor.
 Heavy periods can be a sign of a health problem.
 Painful periods.
 Most women experience menstrual cramps before or during their period at some point in
their lives.
 For some of them it is part of the regular monthly routine.
 However, if the cramps are painful and persistent, you should see a doctor.
Management of Menstrual challenges.

 A doctor can prescribe hormonal medication that can help control heavy bleeding.
 If one experiences heavy bleeding, an iron supplement might help to prevent anaemia.
 Mild to moderate pain or cramps can be lessened (reduced) by taking an appropriate pain
reliever.
 Taking a warm bath might also help to relieve cramps.
 Surgery can also be performed.
 If symptoms persist, always visit a doctor.
Fertilization and Implantation.
 Fertilization is the fusion of a sperm with an ovum in the oviduct (also called the
fallopian tube.)
 During sexual intercourse, thousands of sperms are released into the vagina by the penis.
 Sperms swim through the cervix into the uterus up to the oviduct.

Sperm
Ovum
 Few sperms that reach the ovum try to penetrate it.

 Only one sperm penetrates the ovum.
 When the sperm penetrates the ovum, the surface of the sperm fuses with the nucleus of
the ovum to form a zygote.
 The zygote moves from the oviduct and enters the uterus, attaching itself to the uterus
walls.
 This process is called implantation.
 Once implantation has taken place, the zygote is now referred to as an embryo.
Sex related challenges.
 People born with reproductive or sexual structure that does not fit the category of male or
female are termed as intersex.
 An intersex can be identified at birth, during puberty or in adulthood.
 Intersex is a sex related challenge.
Intersex challenges may be managed through the following ways.

 Educating and advocating against stigmatization of intersex people.
 Eliminating practices like medical operations that can cause harm to intersex people.
 Creating programmes that take care of the needs of intersex people.
 Offering guidance and counselling to intersex people to improve their self-esteem.
 Allowing people with sex challenges to make their own choices and express themselves.
Allowing freedom of choice and expression on sex issues.
Human excretory System-Skin and Urinary system.

 Excretion is the process by which living organisms remove waste products from their
bodies.
 The excretory system removes waste from the body in human beings.
 Examples of waste in the human body include:
 Urine.
 Salt.
 Excess water.
 Carbon dioxide.
Importance of excretion.
 Excretion helps to remove harmful waste products from the body. This prevents them
from accumulating to toxic levels which can cause sickness or death.
The Skin.
External parts of the Skin.
 The skin is the largest body organ.
 The parts of the skin are:
 Hair.
 Sweat glands.
 Epidermis.
Functions of the Human skin.

The human skin has the following functions.
 It covers the whole body protecting against heat, light, injury and infection.
 It helps to make vitamin D when exposed to the sun. vitamin D is important in the body.
 The skin helps to regulate the body temperature. It also helps to prevent dehydration and
protect one from the harmful effects of too much heat or cold.
 The skin is a sensory organ. It allows the body to feel warm, cold, pressure, itchy and
pain.
 New skin cells form at the base of the epidermis. The epidermis also gives the skin its
colour.
 The skin has hair which covers the body providing warmth and protecting the skin. The
hair such as eyebrows and eyelashes protects the eyes and contributes to a persons’
appearance.
 The sweat pores allow sweat to get out of the body.
Waste products excreted through the Skin.

 Epidermis of the skin contains tiny pores through which sweat leaves the body.
 Sweat consists of mainly water and salts.
 Sweating eliminates excess water and some salts from the body.
Body Cosmetics.
 Body cosmetics are substances used to care for the skin to improve its appearance or
smell.
 Usually, they are a mixture of chemical compounds derived from either natural sources or
manufactured ones. The following are expels of cosmetics:
 Lightening creams, powders and colours for the skin, eyes and lips.
 Lotions, shampoos, oils, bleaches, dyes removers for the hair.
 Nail polishes and colours for the nails and lipsticks.
 Hair removers.
 Shower gels, soaps and face wash soaps.
 Skin bleaching and skin tanning preparations.
 Antiperspirants, deodorants and other personal hygiene products.
 Perfumes.
Health effects of cosmetics.
 Most cosmetic products have chemicals that are harmful to the body when used
excessively or over a long period of time.
 Prolonged use of hair products may lead to hair loss, itching, dandruff and thinning of
hair.
 Heavy eye makeup may lead to eye infections.
 Extensive application of nail polish makes nails fragile, thin and they lose their natural
colour.
 Some cosmetics can cause cracks and wrinkles on the skin, which cause infections.
 Lipstick dries the moisture out of the lips. Some lipsticks contain oils and chemicals that
can damage the lips.
 Cosmetics such as deodorants and antiperspirants can cause redness, irritation and
itching.
 Prolonged use of make ups may lead to dizziness, fatigue and contribute to ageing of the
skin. These substances dry out natural oils, vitamins and minerals in the human skin
causing the skin to lose its moisture and texture. Skin develops wrinkles and dry patches.
Effects of Skin lightening creams.

 Skin lightening creams are beauty products used to reduce a pigment called melanin from
the skin.
 Melanin is a skin pigment that makes it black in colour.
 Skin lightening creams are also called skin whitening creams or skin bleaching creams.
 Some people used the skin lightening creams to make their skin tone or complexions
lighter.
The following are some of the effects of skin lightening creams.
 These creams contain chemical substances that may be harmful to the skin. They can
cause skin to have redness, irritation and swelling.
 They cause itchy and flaky skin.
 They cause a burning or stinging sensation. They also make the skin to have uneven skin
tone, thus appearing to have spots.
 They cause kidney, liver and nerve damage.
 They cause the skin to weaken and become vulnerable to injuries and infections.
 They cause scaring.
Uneven skin tone Irritation of the skin Scar on the legs
Healthy lifestyle that promote skin health.
The health of the skin can be improved by doing the following.
1. Drinking plenty of water-this helps to keep the skin stay hydrated.
2. Protect it from the sun-exposing the skin to the sun can cause wrinkles, age spots and
other skin problems increasing the risk of skin cancer. Avoid direct sunlight when the sun
rays are strong.
3. Avoid smoking. Smoking makes the skin look older and contributes to wrinkles.
4. Keep the skin gentle by doing the following.
 Avoid strong soaps and detergents that remove oil from the skin, instead use
mild cleansers.
 Shave carefully to protect your skin. Apply shaving cream, lotion or gel before
shaving.
 After washing or bathing, gently pat your skin dry with a towel so that some
moisture remains on your skin.
5. Eat a healthy diet-eat plenty of fruits, vegetables and whole grains.
6. Manage tress- Stress can make one’s skin more sensitive. This can trigger acne breakouts
and other skin problems.
7. Exercise regularly- exercising increase blood flow and nourishes skin cells.
Parts of the Urinary system.
Ureter
 The Urinary system consists of:

 Kidneys.
 Vessels serving the kidney.
 Ureters.
 Urinary bladder.
 Urethra.
Part Function
Vessels serving  Carry urea in the blood stream to the kidney, where it is removed
the kidney along with water and other wastes in the form of urine.
Kidneys  They are a pair of reddish-brown organs that are bean shaped.
 They are the organs that filter the blood, remove the wastes and
excrete the waste in the urine.
Urinary  It is a hollow organ located in the lower abdomen that is triangular
bladder in shape.
 The urinary bladder is a temporary storage place for urine.
Ureters  These are narrow tubes that carry urine from the kidney to the
urinary bladder.
 Humans have two ureters, one attached to each kidney.
Urethra  This tube allow urine to pass outside the body from the urinary
bladder.
Functions of the Urinary system.

 Kidneys filter urea, salts and excess water from the blood.
 After the waste materials are filtered by the kidneys, they combine to form urine.
 Urine flows out of the kidney through the ureters into the urinary bladder.
 The bladder acts as a temporary store of urine. When it gets full, one feels the urge to
pass out urine through a process called urination.
 Urine flows from the bladder into the urethra and out of the kidney.
Cause and prevention of kidney disorder.

 A kidney disorder is a term used to include any kidney abnormality.
 Kidney disorders can affect the ability of the body to clean blood, filter out extra water
from the blood and control pressure.
 The disorder can also affect the production of red blood cells.
 Examples of kidney disorders are:
 Kidney stones.
 Nephritis.
 Kidney failure.
 Chronic kidney diseases.
Causes of Kidney Disorders.

 Diseases of the immune system, for example diabetes.
 Long-lasting illness such as HIV and AIDS and hepatitis B.
 Some infections that affect kidney may come from other parts of the urinary tract, such as
the bladder, ureter or urethra.
 Defects prefect at birth may block the urinary tract or affect the kidneys.
The following are ways of preventing Kidney disorders.
1. Drinking enough water-dehydration reduces blood flow to your kidneys which can
damage them.
2. Eating a healthy diet-a healthy diet id goo for your kidneys.
3. Controlling blood pressure- high blood pressure can damage the kidney and increase the
chances of getting kidney diseases.
4. Managing blood sugar- high blood sugar levels can cause blood vessels inside the kidney
to become narrow and clogged. This can cause damage to the blood vessels and harm the
kidneys.
5. Exercising- exercise can help one to maintain a healthy weight, control blood pressure,
build strength and endurance and lower the chances of getting diabetes and kidney
diseases.
6. Avoid smoking- smoking may cause certain diseases in the kidneys.
7. Using medicines when necessary- using too much medication may cause kidney diseases.
8. Reducing salt intake- too much salt is associated with high blood pressure.
9. Managing stress- managing stress and anxiety can lower your blood pressure which is
good for your kidneys.
10.Managing regular health check-ups -to detect any kidney problems early.
Healthy lifestyles that promote kidney health.

 Maintaining kidney healthy is very important for overall health and general well-being.
 The following are some of the ways that help to keep the kidney healthy.
 Exercising.
 Controlling blood sugar.
 Monitoring blood pressure.
 Monitoring weight and eating a healthy diet.
 Drinking plenty of fluids.
 Avoid smoking.
 Having regular medical checkups.
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4 FORCE AND ENERGY
 Static Electricity.
 Static electricity is a buildup of electric charges on objects.
 Static electric charge is experienced in the following observations.
 A cracking sound is produced when taking off woolen clothes.
 When you take of your sweater, the hair on your head and arms stand
up erect.
 You hear a cracking sound when you comb dry hair using a plastic comb.
 These observations are due to static electricity which builds up when objects rub
against each other.
Explain what happens when you rub a pen or ruler against your hair then place it
over pieces of paper?
 When you rub a pen on your hair and then place it over pieces of paper, the
pieces of paper move towards the pen.
 When you rub a ruler on your cloth and then pass it over pieces of paper, it
attracts the pieces of paper.
 this shows that hair and cloth have charges that transfer to the pen and ruler
making them attract the pieces of papers.
 These charges are known as static charges.
 The charges are referred to as static because they remain in one area for a while
rather than moving or flowing as current to another area.
Types of Charges.
 There are two types of static electric charges:
a.) Positive charges.
b.) Negative charges.
 If the same amount of negative and positive charges are present on an object,
there is no charges on the object. The object is said to be neutral or electrically
neutral.
Charging Objects-By Rubbing.

 When you bring an inflated balloon close to pieces of paper without actually
touching the papers, the inflated balloon fails to attract the pieces of papers.
 However, when you rub a woolen fabric against the inflated balloon and bring
the balloon close to the pieces of paper the papers are attracted and move
towards the balloon surface.
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Explanation.
 Rubbing the inflated balloon or comb against a woolen fabric or against your hair
transfers a negative charge to both objects. This creates static electricity.
 However, when you bring a dry plastic comb or inflated balloon close to the
materials without rubbing, none of the materials is attracted to it.
 When you rub the inflated balloon or comb against your hair or the woollen
fabric, they become negatively charged.
 If there is enough charge, the balloon or comb will stick to surfaces of neutral
objects such as pieces of paper or pieces of tissue.
 The negatively charged inflated balloon or comb attracts the pieces of paper or
tissue by attracting the positive charges in these materials.
 It left for some time, the attracted items will eventually fall off the comb or the
balloon. This is because the static charges scatter and slowly vanish over time.
(they become weak).
 Finally, the balloon or comb loses its negative charges and the materials get
unstuck.
 Therefore, you can charge an object by rubbing.
Charging Objects-By Induction

 Charging by Induction occurs when a charged object is placed near an object that
is neutral (conductor) without getting in contact with it.
 When an object is charged by induction, it gains charges opposite to the inducing
charges.
Effects of force between charged objects.

 When you inflate two balloons and rub them against hair or wool, they become
electrically charged. They gain the same charges.
 Like charges repel each other and therefore when the balloons are hanged and
moved close to each other, they move apart. This is called repulsion.
 After a while, the charged particles vanish gradually. The balloons are no longer
charged and they move closer.
Demonstrating Repulsion between charged objects.

 To demonstrate repulsion between charged objects, Styrofoam plates are rubbed
at the base with piece of cloth.
 The plates are placed on a flat surface and their bases moved closer to each other.
 The Styrofoam plate gains negative charges from the cloth and becomes
negatively charged. The Styrofoam plates move apart. They repel each other. This
is called repulsion.

Demonstrating attraction between charged objects.
 Using an empty soda aluminum can that is placed on a flat surface, rub an inflated
balloon against your hair or against woolen cloth.
 Hold the inflated balloon close to the soda can (without touching the can) and
observe the interaction between the inflated balloon and the can.
Observation and explanation.

 Rubbing the balloon against hair or wool causes negative charges to move from
the hair or wool to the inflated balloon.
 The balloon, therefore, becomes negatively charged.
 The negative charges on the inflated balloon attracts the positive charges on a can
(Aluminium can)
 Therefore, the can rolls towards the inflated balloon.
 As you pull the balloon away from the can, the can continue to roll towards the
balloon. This is called attraction.
 It one object has negative charge and the other has a positive charge, the two
objects attract each other. Therefore, a positive charge and a negative charge
attract each other.
Use of Static charges in daily life.

Static electricity has several uses or applications in real world life.
 In Printers and photocopiers, static electric charges are used to attract ink or toner
to the papers.
 Static electric charges are also applied in paint sprayers, air filters and dust removal
Photocopy machine Air filter machine Paint sprayer
Safety measures when dealing with Static charges.

 Rain clouds move through the air in the sky building up positive and negative
electric charges.
 When enough charges build up, they jump between the cloud and the ground
causing a spark called lightning.
 The easiest route for lightning to the ground is usually the tallest point from the
ground surface.
 This makes buildings to be the quickest route for lightning spark to the ground.
 This is why many buildings have lightning arresters.
 A lightning arrester is a device used to protect buildings from the effect of lighting.
 A metallic rod, taller than the building is installed in the walls of the building
during its construction.
 One end of the rod is kept out in the air and the other one is buried deep in the
ground.
 The rod provides an easy route for the transfer of electric charge to the ground.
The following should be done to reduce risk caused by static electricity.

1. Avoid wearing rubber-soled footwear, install grounding systems in home
appliances, ground yourself, keep the indoor air humid and keep your skin
moisturized.
2. When there is a thunderstorm find a safe enclosed shelter nearby such as homes
and offices.
3. If you are caught outside during a storm without safe shelter nearby the following
should be done:
 Immediately get off elevated areas such as hills, mountain ridges or
peaks.
 Never lie flat on the ground, crouch down in a ball-like position with
your head tucked and hands over your ears so that you have minimal
contact with the ground.
 Never shelter under an isolated tree.
 Never use a cliff or overhang as a shelter.
 Immediately get out of and away from water bodies, for example
ponds and lakes.
 Stay away from objects that conduct electricity such as barbed wire
fences and power lines.
4. Stay away from concrete floors or walls. Lightning can travel through any metal
wires or bars in concrete walls or flooring.
5. Avoid contact with water during a thunderstorm. Lightning can travel through
plumbing.
6. Avoid using electronic equipment of all types during a thunderstorm. Lightning
can travel through electrical systems.

Electrical Energy.
Sources of Electrical electricity
 Electricity is one of the basic forms of energy.
 Electricity in motion is called electric current.
 Electricity can be obtained from various sources which includes the following:
 Hydroelectric power
 This is production of electricity using the force of moving water.
 Water is held behind a dam and released through a turbine.
 The turbine spins or rotates a generator that produces electricity.
 An example of a hydroelectric power plant in Kenya is the Masinga
Hydroelectric Dam.
Hydroelectric dam
 Geothermal power.
 This is the production of electricity using steam.
 This comes steam from the reservoirs of hot water below the earth’s surface.
 The steam spins a turbine which drive an electrical generator that produces
electricity.
 An example of a geothermal power plant in Kenya is the Olkaria
Geothermal Power Plant.

 Solar power.
 This is energy we get from the sun.
 A solar panel is used to trap this form of energy.
 Solar energy is then used for lighting up homes and to heat water.
 An example of a solar power plant in Kenya is the Garissa Solar Plant.
 Wind power.
 This is the production of electricity from wind.
 When the wind blows, it spins blades on a wind turbine or windmill.
 This generates electricity.
 An example of a wind power project in kenya is the Lake Turkana Wind
Project.

Simple Electrical Circuits.
 An electric circuit is a complete path in which electric current flows from one
terminal to another.
 An electric circuit has a source of energy such as dry cells, current conductors or
wires, a bulb and a switch.
Dry cells
Current conductor or wire
Bulbs with bulb holder
Switch

Ammeter
Voltmeter
 We make electricity by creating an electric circuit.

 For example, when you flip the switch on in the house, you are completing the
electrical circuit. This causes electricity to flow and turn on the light bulb.
 When devices are connected in a circuit one after the other, the circuit is called a
series circuit.
 A series circuit has only one path which the charges flow.
 A parallel circuit had more than one path through which charges can flow.
 The instrument which measures voltage is known as a voltmeter. Voltage refers to
electrical force that would drive electric current between two points.
 A voltmeter is connected in parallel at two pints where the potential difference is
measured.
 When cells are connected in parallel, the current flowing through the circuit is the
same. Therefore, the brightness of the bulbs remains the same regardless of the
number of dry cells.
 When you increase the number of bulbs in a series circuit, the brightness of
the bulbs decreases.
 Bulbs arranged in parallel are brighter than bulbs arranged in series.
 The instrument that measures the electric current flowing in a circuit is an
ammeter.
 An ammeter is connected in series with a circuit so that the current being
measured flows through the ammeter.
 A bulb connected to two cells in series is brighter than a bulb connected to
two cells in parallel.
Conductors and Non-conductors of Electricity.

Classifying materials as Conductors and Non-conductors of electricity.
 The ability to conduct electricity is called conductivity.
 Some materials allow electricity to flow easily through them. These materials are
called conductors of electricity.
 Examples of conductors of electricity are:
 Copper wire.
 Aluminium foil.
 Iron
 Carbon
 Other materials do not allow electricity to flow through them. These materials are
called non-conductors of electricity.
 They are also known as insulators.
 Examples of insulators include:
 Plastics.
 glass.
 Cloth.
 Threads.
 Rubber.
 Paper.
 Stone.
 Dry wood.
 Mattress.
 Sisal.
 Dry sponge

Electrical Appliances in our Locality.
Identifying Electrical appliances in our Locality.
 Electrical appliances are devices that use electricity to work.
 They are found in various places in our locality such as at homes, offices, hospitals
and schools among other places.
 They include the following appliances:
 Electric cooker.  Laptop.
 Iron box.  Desktop computer.
 Fan.  Refrigerator.
 Television.  Phone.
 Printer.  Radio.
 Electric kettle.  Heater.
Uses of Electricity in the Environment.

 Electricity has many uses in different environments.
 Some uses include:
 Running machines.
 Cooking.
 Heating.
 Lighting.
 Refrigerators
 Entertainment.
Safety measures when handling electrical appliances.

 Safety measures are put in place when handling electrical appliances to prevent
any dangers brought about by electricity.
Possible danger of electricity. Safety measure to apply
Overloading a single socket Do not overload a single socket
Inserting metallic objects or fingers into Do not insert objects or fingers into
the sockets. sockets
In case of a power outage or leakage. Switch of the main switch.
Naked exposed electric copper wires Insulate or mask the naked wires or
cables.
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Wet hands Dry your hands.
Illegal connection. Do not connect electricity illegally.
Using spoiled, broken or defective Repair broken appliances, devices and

appliances. sockets.
Splash water near sockets Do not splash water near sockets.
Safety measures to observe when using electrical appliances.

 We should switch off the main switch when not using any electrical appliance.
 We should repair broken appliances, devices and sockets.
 We should not touch naked wires with bare hands.
 We should not handle electrical appliances or switches with wet hands.
 We should not over load a sing socket.
 We should not insert objects or fingers into sockets.
 We should not splash water near sockets and switches.
 We should not attempt to connect electricity illegally.
Magnetism.
 A magnet pulls objects towards it or pushes objects away from it.
 When a magnet pulls something, it attracts it.
 When a magnet pushes something away from it, it repels it.
 Magnets can move, pull or push magnetic objects without touching them. This
invisible force is called magnetism.
Identify Poles of a Magnetic.

 When you place iron fillings on a sheet of paper and place a magnet bar on the
sheet of paper, you will observe that the iron fillings are attracted more towards
the region close to the two ends of the magnet bars.
 Poles of a magnet are said to be near the end of the magnet bars.
 All magnets have two ends that are called magnetic poles.
 These are North pole and South pole.
 Most magnets are labelled N and S where N stands for North pole while S stands
for south pole.
 The magnetic force of a magnet is strongest at the poles. This means that the poles
attract and repel more than the other parts of the magnet.
Magnetic and Non-magnetic materials.

 A magnet attracts some materials.
 Materials attracted by a magnet are called magnetic materials.
 Magnetic materials include objects such as iron, steel, nickel and cobalt.
 Some materials are not attracted by a magnet. These materials are called non-
magnetic materials. They include objects such as plastic, wood, copper and
Aluminium.
The force between like and unlike poles.

 When you move closer two magnet bars suspended using a thread you will
observe that some sides repel and other attract each other.
 You notice that the North pole of one magnet and the south pole of the other
magnet pull each other and stick together. This is called attraction. This shows
that the unlike poles of magnet attract.
Unlike poles attract
Like poles attract
 The north pole of one magnet pushes a way the north pole of another magnet.
this is called repulsion. this shows like poles of magnet repel.
 Similarly, the south pole of one magnet pushes a way the South pole of another
magnet.
 This also shows that like poles of a magnet repel.
 This experiment shows the law of attraction and repulsion.
Finding the Direction of A freely suspended Magnet.
 When you suspend a bar magnet freely in the middle using a string it will turn
until it stops.
 The magnet aligns itself to the Earth’s North pole and South poles when it stops.
 The magnetic pole pointing towards the Earth’s North magnetic pole is the
magnet’s North pole.
 The magnetic pole pointing towards the Earth’s South magnetic pole is the
magnet’s South pole.
Uses of Magnets in day to day life.

 Magnetic recording media-computers have hard disks that record data on a thin
magnetic coating.
 Credit, debit and ATM cards-all of these cards have a magnetic strip on one side.
 Common televisions and computer monitors-some televisions and computer
screens contain a device that has an electromagnet.
 Electric guitars-they use magnetic devices to convert the vibration of guitar strings
into electric currents that they amplify.
 Speakers -most speakers use magnets to generate sounds.
 Medicine-Hospitals use magnetic devices (magnetic resonance imaging) to spot
problems in a patient’s organ.
 Toys- magnets are often used in children’s’ toys.
 Picking up magnetic items-iron nails, staples, tacks and paper clips that are either
too small, too hard to reach or too small for fingers to hold can be picked using
magnets. Some screw drivers are magnetized for this purpose.
Topical questions.
1. Explain how material get charged?

2. Which two ways can you use to give objects charges?
3. What are the dangers of static charges?
4. How can we keep safe from the dangers of lightning?
5. How can you create awareness to prevent damages caused by lightning?
6. What are the sources of electricity?
7. What are the differences between conductors and non-conductors of electricity?
8. Identify electrical appliances used in your area.
9. Describe safety measures you would observe when using electrical appliances.
10.What are sone of the uses of electricity in your environment?
11. Name 4 magnetic and 4 non-magnetic material in your locality.
12.How do you identify magnetic materials in your environment?
13.What will happen when the North pole and south pole of different magnets are
brought together?
14.How are magnets used in day to day life?
15.Iron fillings and pins accidentally fell into maize flour. Explain how you would
separate the two materials to obtain pure maize floor.
16.Ruth tried to pick a sweet using a magnet. Explain what happened and why it
happened.
17.Rotich took a soda from a refrigerator in town. He noticed that the door quickly
locked and sealed itself. Give the reason for this.
Self-Assessment report.
Tick in the box that describes your performance of the competencies outlined.
Competency Yes I need help
Demonstrate the existence of static charges in objects
Charge objects using different methods.
Demonstrate the effect of force between charged objects.

Appreciate the use of static charge in daily life.
Identify various sources of electricity in their
environment.
Set up simple electrical circuits in series and parallel
using dry cells, bulbs, ammeter and voltmeter.
Classify materials as conductors and non-conductors of
electricity.
Identify electrical appliances in their locality.
Identify safety measures when handling electrical
appliances.
Appreciate the use of electricity in their daily life.
Classify materials in the environment as magnetic and
non-magnetic.
Investigate the force between like and unlike poles of
magnets.
Identify the uses of magnets in day to day life.
Appreciate the applications of magnets in day to day life
Additional comments
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Knowledge and Skills gained from Integrated Science.

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Oxidizer  The substance can

Caution! Avoid exposure to

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Caution! Keep away from

Toxic  The substance is

Common Accidents in the Laboratory and Related First Aid measures.

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Ingestion of Harmful substances If the victim is unconscious:

Safety measures and regulations in the laboratory.

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Basic Science Skills.

c.) Classification skills.

d.) Measuring skills.

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f.) Predicting skills.

g.) Conclusion skills.

What is the importance of reading Packaging labels?

What are Basic quantities?

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 Volume =length x width x height (m x m x m) or m3 (cubic metres).

 Area (square or rectangle) = Length x width (m x m) or m2 (square metres)

Applying the International System of Units (SI)

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Area =1/2 x base x perpendicular

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 Area of irregular shapes.

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Observing A Bunsen burner.

Functions of the parts of a Bunsen burner.

 Apparatus and Instruments for Temperature.

 Apparatus and Instruments for Measuring Length.

Part of metre rule.

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Burette Graduated cylinder Pipette

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 Apparatus and Instruments for Measuring time.

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Handling of common laboratory apparatus and instruments.

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Handling a light microscope.

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Make order of Quality Notes, Exams, Schemes of

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Melting point of pure substances (Ice).

Melting point of Impure substances (Candle wax).

Determining Boiling points of Pure and Impure substances.

Requirements for the

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Observations and conclusion & Explanation.

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 Observation and explanation.

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 Observation and explanation.

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 Observation and Explanation.

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Questions from the experiment.

 Observation and explanation.

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 Observation and explanation.

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 Observation and explanation.

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 Observation and explanation.

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ACIDS, BASES AND INDICATORS.