Grades 8 & 9 Integrated Science Notes (Zambia) PDF

By Mwanza Matthews GRADES 8 AND 9 INTEGRATED SCIENCE HUMAN BODY 1. (1) Identify organs of the human reproductive system.  Male: testes, sperm duct, scrotum, urethra and penis. Front view Side view...

By Mwanza Matthews GRADES 8 AND 9 INTEGRATED SCIENCE HUMAN BODY 1. (1) Identify organs of the human reproductive system.  Male: testes, sperm duct, scrotum, urethra and penis. Front view Side view  Female: ovaries, oviduct, uterus, cervix, virginal. Front view Side view Mwanza Matthews Page 1 of 53  (2) Explain the functions of the parts of the reproductive system. Males  Penis - depositing sperms into the vagina  Testes - producing the sperm cells and the male sex hormone, Testosterone.  Scrotum - skin sac that holds the testes outside the body to Keep them cooler than the body temperature.  Epididymis - Long, coiled tube that stores sperm cells.  Sperm duct - tube that transports sperm cells from the testes to The urethra  Urethra - tube that transports the semen through the penis and Urine from the bladder to the outside of the body. Females:  Ovary - producing the ovules (eggs)  Cervix - lower narrow end of the uterus where it joins the Vagina.  Oviduct - where fertilization occurs  Vagina - it accepts the penis during copulation and is the Birth canal for the feotus during normal child birth.  Uterus - where the embryo develops during pregnancy. (3) Identify changes associated with puberty for both male and female. Males:  pubic hair grows at the base of the penis  the penis enlarges  the testicles grow  wet dreams  chest enlarges Mwanza Matthews Page 2 of 53  Females:  The breasts grow  Pubic hair appears on the vulva  Hair grows in the arm pit  The body grows in height  The hips become wider.  The first menstruation occurs (4)Explain the importance of observing personal hygiene of the reproductive organs.  Avoids inflections  Avoids diseases (5)Describe the process of fertilization in human beings.  Fertilization is the fusion of the sperm and an egg (ovum) in the oviduct to form a zygote. Contact between sperm and ovum makes the sperm to release enzymes which break through the wall of the ovum. A small path is created that allows the head of the sperm to enter the ovum. The nucleus of the sperm and the nucleus of the ovum then fuse (i.e. fertilization).  Once fertilization has occurred, the wall of the ovum becomes thickened to prevent further entry of another sperm. The zygote formed during this process contains information from both the mother and the father. (6)Explain the functions of the parts important for development of the embryo. PLACENTA  Allows the nutrients to pass from the maternal blood into the foetal blood  Allows the waste products to pass from foetal blood to the maternal blood  Allows carbon dioxide to pass from foetal blood to the maternal blood  Allows oxygen to pass from the maternal blood to the foetal blood AMNION  This membrane ensures that the liquid that surrounds the developing embryo/ foetus does not drain away. UMBILICAL CORD  This cord transports blood from the embryo /foetus to and from the placenta. Mwanza Matthews Page 3 of 53  AMMINIOTIC FLUID  This fluid allows the foetus to move freely inside the uterus while it is still developing  It ensures that the development of the foetus will be normal and that the foetus will have symmetrical growth  protects the foetus from mechanical shocks (being bumped)  Protects the foetus from dehydration. (7) Describe Gestation period and Birth. Gestation period  Gestation period is the period of foetal development in the uterus until birth. In humans the average length of the gestation period is 266 – 270 days (38 – 38.5 weeks) or 9 – 9.5 months.  Stages of embryo development, that is, zygote – embryo - foetus and baby. Birth  Birth happens at the end of a pregnancy when one or more newborn infants are pushed out from a human’s uterus.  The stages of birth are: - The dilation and shortening of the cervix. - The descent and birth of the infant. - The expulsion of the placenta. HEALTH – NUTRITION 1. Describe the different types of food nutrients.  Carbohydrates: a food type that can be broken down to release energy; also known as starch.  Protein:a food type that contains nitrogen; they make up the structural parts of body cells and tissues.  Lipids: a food type that includes fats and oils.  Minerals salts: inorganic substances which are essential in small amounts in a person’s diet for good health.  Vitamins: an organic substance that is essential in small amounts in a person’s diet for normal growth and good health. Mwanza Matthews Page 4 of 53  2. Describe the dietary needs for different persons  Baby - more proteins and mineral salts  Pregnant Mother - more proteins, calcium, lron and vitamins D. 3. Identify common nutritional deficiency diseases of symptoms and their diseases Kwashiorkor Symptoms  Hair Loss  Swollen stomach  Swollen ankles, feet and hands  An enlarged fatty liver  Diarrhea  Anemia  Loss of teeth  Loss of skin colour  Loss of appetite Marasmas Symptoms  Swollen stomach  Dry skin  Loose skin folds  Extreme hunger  General tissue and muscle wasting Rickets Symptoms  Aching bones  Dental problems  Muscle weakness Scurvy Symptoms  Tiredness  Spongy gums  Bleeding from the mucus membrane  Pale skin Mwanza Matthews Page 5 of 53   Depression Anaemia Symptoms  Pale yellow skin  Weakness  Hair loss  Fainting  Missed menstrual cycle  Depression  Mouth ulcers 4. Describe the importance of children’s clinics.  For nutrition, growth and monitoring.  Providing immunization  Providing nutritional advice ENVIRONMENT WATER, AIR AND LAND POLLUTION 1. Explain what pollution is.  Pollution is addition of harmful substances to the environment. 2. Identify different types of pollution to the environment.  Water pollution  Air pollution  Land pollution 3. Identify causes of pollution to the environment Water pollution- Causes  Untreated sewage  Washing clothes in rivers and streams,  chemicals from factories and farm land Air pollution Causes  Smoke, dust, fumes  Mwanza Matthews Page 6 of 53 Land pollution Causes  Garbage, effluents from factories 4. Describe the effects of pollution in the environment Water pollution  Outbreak of diseases  Poisonous  Effects aquatic life Air pollution  Breathing difficulties  Global warming  Acidic rain Land pollution  Outbreak of disease  Unpleasant smile  Unproductive land 5. Describe ways of preventing pollution of the environment.  Conservation of resources’ -3Rs reduce, Re- use and Recycle of pollutants. PLANTS AND ANIMALS (PLANTS CELLS) (1) Identify the main parts of the microscope.  Mirror  Stem  Lens  Stage  Eye piece  Adjustment knob Mwanza Matthews Page 7 of 53  (2) Examine the plant cell structure using a microscope.  Cell wall  Cell membrane  Cytoplasm  Nucleus  Chloroplast  Vacuole PLANT GROWTH AND NUTRIENTS 1. Identify regions of growth of a plant  Shoot  Roots  Stem 2. Demonstrate responses to stimuli in shoots and roots Roots and shoots of plants determine the growth rate of a plant. These are dependent on the response of the root or shoot to external stimuli. Shoots respond to light. The response of shoots to light is called phototropism. The figure below illustrates the response of shoots to light. Mwanza Matthews Page 8 of 53  Note:The response of the root to light is negative and this is called negative phototropism Roots however, respond positively to gravity, hence they are positively geotropic. We call this response as positive geotropism. The response of roots to gravity is beneficial in that the plant is able to get fixated in the soil; it is able to absorb water and mineral salts. Plant roots also respond to water the same way they respond to gravity. The response of plants to water is hydrotropism. Experiment;To find out about geotropism in roots and stems using a newly germinated bean. Materials: germinating bean seeds, beaker or glass jar, cotton wool. Method- soak the cotton wool in water - Place the cotton wool into the beaker. - Place the germinating bean seeds between the walls of the beaker and soaked cotton wool so that they can be seen through the glass wall of the beaker. - when positioning the seeds, arrange at a 45⁰ angle so that their radicals (roots) point upwards and their plumules (shoots) point downwards - Place in a warm, sunny place. - Allow standing for three to five days. Ensure that the cotton wool is kept moist at all times - draw your seed in the correct biological way - Explain your results and observations Observations/results  The roots of the germinating seeds curve away from the top of the beaker and grow downwards.  The shoots of the germinating seeds curve away from the bottom of the beaker and grow downwards. The figure below illustrates predicted results for the experiment described above. Mwanza Matthews Page 9 of 53  Conclusion This shows that:  The stems are negatively geotropic as the shoots are growing upwards (away from the earth)  The roots are positively geotropic as they are growing downwards (towards the earth). 3. Describe nutrients important to plant growth - Three major elements are:  Potassium  Nitrogen  Phosphorous These elements are present in the form of salts such as potassium nitrate, potassium phosphate and calcium nitrate. Other nutrients required by plants are;  Calcium  Magnesium  Sodium  Iron  Sulphur. The following table describes the function and effects of deficiency of these nutrients in plants. Nutrient Function Effects of deficiency Nitrogen Constituents of -Chlorosis (yellowing) in older amino acids and leaves. proteins, co- -poor growth of all plant organs enzymes and chlorophyll phosphorous Useful in the Stunted growth and leaf fall formation of ATP and regulation of several enzyme systems Potassium Very important in Reduced plant growth the formation of -reduced root, fruit and seed cell membrane development -chlorosis ((yellowing) of leaves. -brown scorching of leaves -curling of leaf tips Mwanza Matthews Page 10 of 53  Calcium Useful in the -poor growth of plant formation of the middle lamella Magnesium Is a component of General yellowing of leaves. chlorophyll -drying back of the meristem of molecule roots and shoots Sulphur Formation of plant General yellowing of leaves proteins Sodium Reduced plant growth Iron Chlorosis of leaf veins inhibition of photosynthesis and cellular respiration 4. Investigate how plants obtain dissolved mineral salts from the soil Plants absorb all mineral salts that they need through their roots in the form of mineral salts. Roots have tiny hair like structures, called root hairs, near their tips. These root hairs allow water and dissolved mineral salts (ions) from the soil to enter them. Water moves into the root hairs by a process known as osmosis. The process by which the mineral salts move into the root hairs is known as diffusion. The water with the dissolved mineral salts is carried from the roots up through the stem into the branches, leaves and flowers of the plant. This upward movement of water in the plant is due to a number of factors. The most important factor is the suction force that is created by a process known as transpiration. Transpiration is the loss of water vapour from the parts of the plant that occur above the ground, mainly the leaves. Experiment:-To show how plants absorb water and dissolved mineral salts Materials; two beakers, red/blue ink (to represent dissolved minerals), coloured chalk dust (to represent insoluble particles, scarpel/razor, two young plants such as black jack ( Bidenspilosa). Method: -Pour an equal amount of water into both beakers. -To one beaker, add an equal volume of red/blue ink where as to the other beaker add chalk dust. - Carefully remove two young plants from the soil and place one plant into each beaker. - Place the beakers on the window sill in the classroom or in a sheltered well-lit position. Mwanza Matthews Page 11 of 53  -Allow them to stand for one hour and observe the colour of the stems of both plants -Remove the plants from the beakers -Use the blade to cut the cross section through the stem and main (tap)root. -Carefully observe each cross section and record your observations in a table like the one below. -If possible, observe the cross sections using a magnifying glass or microscope water and chalk dust suspension observation plant water and ink solution water and chalk dust part suspension Root Stem The cross section of the root and stem from the plant that was placed into the ink solution shows the colour of the ink in the areas of the root and stem that correspond to the position of the vascular bundles (i.e. xylem cells). This shows that the ink together with the water has been absorbed by the roots and past into Mwanza Matthews Page 12 of 53  the vascular bundles (xylem cells for transport up the plant to the leaves. This means that minerals dissolved in water will be transported within plants The cross section of the root and stem from the plant that was placed in the chalk suspension does not show the colour of the chalk anywhere. This shows that unless a substance, such as a mineral, is dissolved in the water, a plant will not absorb that substance. 5)Identify sources of plant nutrients Sources of plant nutrients are: (i) Organic fertilizers ( manure, compost),- these are dead, decaying substances such as leaves, cow dung, poultry manure and stalks of cereals, for example, maize, sun flowers and bean stems. (ii) Inorganic (artificial) fertilizers- these are made in factories by industrial companies such as nitrogen chemicals. Examples of these fertilizers include; urea, D compound and ammonium nitrate. 6). Explain the advantages and disadvantages of inorganic and organic fertilizers. Advantages of using organic fertilizers Organic fertilizers make the soil rich. Adding humus for example, -Improves soil texture by creating air spaces in between the soil particles. -Improves water retention (ability to hold water) in the soil). -Makes the soil soft for cultivation -enables bacterial action in soil Disadvantages of using organic fertilizers -May not be easily available to farmers -They take a long time to decompose and so the nutrients take a long time to be available to plants. -They may promote the growth of weeds in the field. -They may encourage worms, termites and ants which feed on crops, causing them harm. Advantages of using inorganic fertilizers - Inorganic fertilizers are easy to use on large areas of land - They are easy to transport over long distances - They are quick acting - They are effective if correctly bused and greatly increase crop yield. Disadvantages of using of using chemical fertilizers Mwanza Matthews Page 13 of 53  - They are costly because farmers must buy them - Chemical fertilizers change the amount of acidic substances in the soils, for example, soils may become acidic. 7). Explain the effects of excessive use of inorganic fertilizer to the soil; - The soils become too acidic, which causes the plants to stop growing properly or to die - Excessive use inorganic fertilizers promote overgrowing of plants. PLANTS AND ANIMALS 1. Describe the basic structure of an animal cell It is made up of the following parts:  Cell membrane  Cytoplasm  Nucleus 2. Describe the functions of the parts of the cell  Cell membrane - selectively permeable to materials.  Nucleus - controls all the activities of the cell.  Cytoplasm - jelly - like material that fills a cell and contains organelles which perform functions that is vital for the survival. 3. Identify different features in the basic structure of an animal cell and a plant cell. Plant cells Animal cells They have a definite shape They have an irregular shape. They have cell walls. They have no cell walls. Some have chloroplasts. None of them have chloroplasts. They usually have a large cell vacuole; if They usually have no vacuoles; if present, they there is more than one vacuole, they are are small and numerous. usually all big. Mwanza Matthews Page 14 of 53  MATERIALS AND ENERGY Composition of matter 1. Describe the composition of matter. All matter is made up of particles called atoms (basic building block of matter). Most atoms can combine with other atoms to form molecules. An element is a form of matter made up of only one kind of atom. 2. Describe the basic structure of atoms.  Nucleus (centre) surrounded by electrons in shells 3. Identify common atoms using symbols  Carbon (C)  Oxygen (O)  Copper (Cu)  Aluminum (Al)  Hydrogen (H)  Nitrogen (N)  Iron (Fe) 4. Demonstrate the formation of simple molecules using models of atoms: Molecules  Oxygen (O2)  Hydrogen (H2)  Water (H2O)  Carbon dioxide (CO2) A:Anoxygen molecule represented by two identical spheres joined together. B: An oxygen molecule represented by the nucleus and energy level with electrons for both atoms. The four blue balls at (a) represent the four shared electrons that join the two oxygen atoms. A B Mwanza Matthews Page 15 of 53  C: A hydrogen molecule represented by two identical spheres joined together. D:A hydrogen molecule represented by the nucleus and energy level with electrons for both atoms. The two blue balls at (a) represent the two shared electrons that join the two hydrogen atoms. D C E: A nitrogen molecule represented by two identical spheres joined together. F:A nitrogen molecule represented by the nucleus and energy level with electrons for both atoms. The six blue balls at (a) represent the six shared electrons that join the two nitrogen atoms. E F G: A carbon dioxide molecule represented by two identical red spheres representing oxygen atoms that are joined by a black sphere representing a Mwanza Matthews Page 16 of 53  carbon atom. H:Acarbon dioxide molecule represented by the nucleus and energy level with electrons for both atoms. The four blue balls at (a ) and (b) represent the two groups of four shared electrons that join the two oxygen atoms to the carbon atom. G H I: A water molecule represented by two identical white spheres representing hydrogen that are joined by a red sphere representing oxygen. J:Awater molecule represented by the nucleus and energy level with electrons for both atoms. The blue ball at (a) and (b) represent the two shared electrons that join the two hydrogen atoms to the oxygen atom. PHYSICAL CHANGE OF STATE 1. State what physical change is?  It is change from one state to the another Mwanza Matthews Page 17 of 53 2. Describe the arrangement of atoms in the three states of matter.  Solids - Atoms very close together  Liquids - Close together  Gas - Spread far apart 3. Identify the temperature at which water changes state. - Melting point is the temperature at which a solid changes into a liquid. The melting point of ice is 0℃. - When a liquid is heated it changes into a gas. This process is called evaporation. Once the liquid reaches a certain temperature it starts - to boil. The temperature at which this happens is called boiling point. The boiling point of water under normal conditions at sea level is100℃. - Interpreting the graph. A. The temperature of ice rises steadily as heat is observed by ice. B. Ice is been converted to water at the melting point. Although heat is absorbed, the temperature remains constant through the change. C. Added heat now increases the temperature of the liquid until the boiling point is reached. Mwanza Matthews Page 18 of 53  D. At the boiling point, the vapour pressure of the water equals the external atmospheric pressure. Added heat is used to overcome the intermolecular forces. The temperature remains constant until the liquid has completely vapourised. E. The temperature of the steam increases steadily as the heat increases. MIXTURES 1. Explain what a mixture is.  Substance made up of two or more substances that are not chemically combined. 2. Identify different types of mixtures: (a) Homogeneous mixture, examples:  sugar water (sugar solution)  Sea water  Air  Blood (b) Heterogeneous mixture, examples  Soil  Salt  Fruit salad  sand in water  Marbles  Corks  Oil and water  Soups and stews 3. Identify methods of separating mixtures  Filtration  Simple distillation  Fractional distillation  Evaporation  Magnetization  Crystallization 4. Explain some of the industrial applications of separation techniques:  Making sugar  Formation of salt from sea water  Separation of scrap metals. Mwanza Matthews Page 19 of 53  MASS AND WEIGHT 1. State what mass is? - Mass is the amount of matter in a substance. 2. How can you measure the mass of different objects? - Mass is usually measured in kilograms (kg) and grams (g). - We can measure mass using a beam balance. A simple beam balance employs already known masses to determine the unknown masses. Other balances used to measure the mass of different objects are the triple beam balance and the digital or electronic balance. Example: measure the mass of salt. Place an empty beaker on the triple beam balance and record its mass as M1. Pour the salt in the beaker and record the new mass as M2 (mass of beaker and salt). Calculate the difference between M1 and M2. This gives the mass of the salt. Repeat the experiment using other substances such as flour or rice. 3. State what weight is? - Weight is the pull of gravity on the mass of an object. Weight = mass × acceleration due to gravity Note: Acceleration due to gravity is 10N/kg on earth 4. How can we measure the weight of a given object? We measure weight with a spring balance and its unit is Newton (N). When measuring weight, hold a spring balance or attach it to a fixed surface by its ring at the top. Attach the object you want to weigh to the hook at the bottom of the balance. This causes the spring in the balance to stretch. Measure the weight of the object then. The marker on the outside of the spring balance moves down the scale of the spring balance. Mwanza Matthews Page 20 of 53  a spring balance 5. Calculate the weight of a substance with a given mass. Example: (i) Calculate the weight of a 20kg stone on earth (acceleration due to gravity is 10m/s2) Solutions Weight = mass × acceleration due to gravity. Weight = 20kg × 10m/s2 Weight = 200N Note:When an object is taken to another planet, the weight differs from the weight on earth, while the mass remains unchanged. 6. Distinguish between mass and weight. - Mass is the quantity of matter in a body while weight is the pull of gravity on a body. - Mass is measured with a beam balance while weight is measured with a spring balance. - Mass is measured in grams (g) or kilograms (kg) while weight is measured in Newton (N). - Mass is constant while weight varies from place to place DENSITY 1. Explain the meaning of density Density is mass per unit volume of a substance. 𝑚𝑎𝑠𝑠 Density = 𝑣𝑜𝑙𝑢𝑚𝑒 Mwanza Matthews Page 21 of 53  - The unit for density is grams per cubic centimeter (g/cm3) 2. Demonstrate how to determine the densities of different substances (i) Determining the density of a stone. - Weigh the stone by placing it on a beam balance. Read and record its mass (m) - Pour water into a measuring cylinder and record its volume as V1. - Tie a thin string to the stone and gently lower it into the water until it is fully submerged (under water). - Record the total volume of the water and the stone as V2. - Now calculate the density of the stone as follows: Density =m v2 – v1 The figure below illustrates how the density of a stone can be determined. (ii) To determine the density of a block of wood. Draw a table for the results like the one shown below. Mass Length (L) Width (W) Height (H) Volume (g) (cm) (cm) (cm) L × W × H (cm3) Mwanza Matthews Page 22 of 53  -Using a beam balance, measure the mass of the block of wood and record your results in the table above. - Measure and record the length, width and height of the block of wood. - Calculate the volume of the block of wood using the formula, V=L×W×H or V=l×b×h - Calculate the density of the wooden block using the formula 𝑚𝑎𝑠𝑠 Density = 𝑣𝑜𝑙𝑢𝑚𝑒 (iii) To determine the density of a liquid e.g. water. - Draw a table for your results like the one shown below Liquid (A) Mass of (B) Mass of (C) Mass of water (D) volume of cylinder (g) cylinder + C=B–A water water (g) (g) (cm3) Water - Carefully determine the mass of the empty measuring cylinder using the beam balance. - Record this in column A in the table above. - Pour water into the measuring cylinder and record the volume of this water in column D. - Now place the measuring cylinder with the water on the beam balance. Record the mass in column B. - Calculate the mass of water in column C. - Use the data recorded in your table to calculate the density of the water. 3. Demonstrate that an object will sink or float on a liquid. - Denser objects sink and less dense objects float in relation to the density of a liquid. Mwanza Matthews Page 23 of 53  Oil Wood WaterWater Stone 4. Describe how vessels float: - Vessels float because they have a larger volume and are less dense.Their average density is less than that of water. 5. Explain the effects of overloading vessels. - It causes sinking of vessels - It causes accidents HEAT TRANSFER 1. Demonstrate the types of heat transfer. The types of heat transfer are conduction, convection and radiation. - Conduction is the transfer of heat through solids. In conduction, heat is transferred from the hot region to the cold region by vibration of particles. - Conduction can be demonstrated using the following experiment: In this experiment, the pins fall off one by one starting with pin A. This is because particles at the end of the wire in the flame become hot and start to vibrate more strongly. As these particles vibrate, they hit other particles next to them and make them vibrate as well. In this way the hot particles transfer some of their heat to the Mwanza Matthews Page 24 of 53  cooler particles next to them. This continues until heat reaches the other end of the wire. In this way we say heat has been conducted along the wire. Convection is the transfer of heat through liquids and gases. In convection, heat is carried by the particles from the hot region to the cold region. Convection can be demonstrated as illustrated in the experiment below: In this experiment, used tea leaves are sprinkled into the water and the water is heated gently. Observation When the water is heated in the experiment above, the hot particles of the water at the bottom rises to the top. At the same time, the cold particles of water at the top moves down to the bottom and also become heated. This process of the hot articles rising and cold particles moving downwards results in convection currents which are shown by the movement of tea leaves. Radiation is the method of heat transfer from the source without requiring particles of a solid, liquid or gas. The heat reaching your hands when you hold them near a fire reaches them by radiation. Heat from the sun reaches us also by radiation. 2. Investigate the movement of heat in matter. - The following experiments can be performed to investigate the movement of heat in matter. (a) In solids Mwanza Matthews Page 25 of 53  - Place the concave end of a spoon over or in the source of heat for some time. - If you keep your hand on the handle of a spoon, you would soon feel warm. This is because heat has been conducted from the source to the end of a spoon and finally to your hand. (b) In liquids As in an experiment described in question (1) above under convection in liquids. This experiment can also be performed using a few crystals of potassium permanganate dropped into the bottom of the beaker through a straw. The result is the same. (c) In air Fix a box with two chimneys with a candle at the bottom of one of them as shown in figure below. Light the candle and observe through the transparent plastic wrap. Put a smoldering paper near the top of the cold chimney and make observations. Observation The smoke is carried down the cold chimney and up the hot chimney by convection currents in the air. Conclusion Heat travels through the air by convection currents. 3. Describe how a vacuum flask works. A vacuum flask is a device that keeps liquids hot or cold by preventing heat transfer. Main parts of a vacuum flask Mwanza Matthews Page 26 of 53  The main insulator in the vacuum flask is the inner glass container which has double silvered walls, namely, inner wall and outer wall. These silvered walls reduce heat loss by radiation. This is done by the inner wall reflecting heat back into the liquid. In this way a hot liquid put into the flask remains hot for a long time. Heat gain is reduced by the outer wall reflecting heat towards the outer housing (outer casing). In this way a cold liquid put into the flask remains cold for a long time. Between the inner wall and the outer wall is a vacuum to reduce heat loss or gain by convection or conduction. A cork or plastic stopper in the mouth of the flask reduces heat loss or gain by convection and conduction. The outer housing protects the glass vessel from damage. The sealed tip on the inner glass container is where the air was sucked out from between the walls. HEAT AND EXPANSION OF SUBSTANCES 1. Demonstrate expansion of substances. - Expansion is the increase in amount of space used by another due to heating. Expansion of solids - Different solids have different expansion rates from fastest to slowest; the rates of expansion for some solids are aluminum, copper, brass and steel. For example, aluminum expands more than copper does when they are heated to the same temperature. - This difference in expansion can be shown by heating a bimetallic strip. - A bimetallic is a strip of two different metals joined together. When heated or cooled, one metal expands or contracts faster than the other, causing the strip to bend as shown below. Mwanza Matthews Page 27 of 53  Expansion of liquids Liquids are kept in containers because they have no fixed shape. To see the increase in volume of a liquid due to heating, we also heat the container in which the liquid is.The container will also expand Note: if the liquid level in the container rises as it is being heated, then the liquid has expanded more than the container. The experiment below illustrates that liquids expand when heated. In this experiment, the water level falls at first, and then rises steadily. The initial drop in the water level occurs because the flask expands first, before the heat reaches the water. The next rise in the water level is due to the volume of the water increasing as it is heated. We can therefore conclude that liquids expand when heated. Expansion of gases The expansion of gases is so large that we can ignore the expansion of the containers they are stored in. To show that gases expand when heated, the experiment is set as shown below. Mwanza Matthews Page 28 of 53  In this experiment, bubbles start coming out of the submerged delivery tube in the beaker due to the expansion of the air inside the flask caused by the heating. 2. Describe the use of the expansion of different substances in everyday life. - In thermometers. In most thermometers the liquid used is mercury because it expands quickly when heated. Other thermometers use alcohol. - In thermostats: thermostats are devices used to maintain temperature between certain limits in electrical appliances and indoor areas. These devices use bimetallic strips as switches. - In internal combustion engines:Internal combustion engine, the mixture of fuel and air is drawn into the cylinder where it is ignited by a spark from a spark plug. This hot air now expands rapidly and pushes on a piston, pushing it down. When the piston moves, it pushes a crankshaft that turns the wheels. Most internal combustion engines operate using four strokes, which repeat themselves over and over. 3 Explain the effect of expansion and contraction of substances. - Fracture of bridges. - Breakage of glass e.g. window pane. - Buckling of rail tracks. REFLECTION AND REFRACTION OF LIGHT 1. Describe what reflection is. - Reflection is the bouncing of light off a surface. - Light that bounces off a smooth surface such as a mirror is reflected in a regular way while light bouncing off a rough surface is reflected in an irregular way. The figures below illustrate regular (smooth) reflection and irregular (diffused) reflection. Mwanza Matthews Page 29 of 53  2. Investigate the characteristics of reflection of light in a mirror. This can be done by carrying out an experiment as follows: - Place the plain paper on the cardboard and fix it at the edges using paper clips. - Draw a horizontal line on a sheet of plain paper and then draw a perpendicular line to the horizontal line. This is the normal. - Measure a 300 angle to the perpendicular line and draw the line AB. - Place a plain mirror upright on the horizontal line with the reflecting surface facing the normal. - Fix three drawing pins P.Q and R on the line AB representing the incident ray. Look into the mirror and find the images P, Q and R. - Fix pins S, T and U to the paper in line with the image P, Q and R, as shown in figure below. - Measure the angles formed that represent the angle of incidence and the - angle of reflection. - Repeat the experiment using different angles. Observation The angle of incidence and the angle of reflection are always equal, no matter what the size of the angle of incidence is. Conclusion When light is reflected, the angle of incidence is always equal to the angle of reflection. 3. Describe what refraction is Mwanza Matthews Page 30 of 53  - Refraction is the bending or changing of direction of light rays when they pass from one material into another. Refraction takes place at the boundary of the two media (singular – medium). - When light passes from a less dense medium to a denser medium, it is refracted towards the normal. - Light travelling from a denser medium to a less dense medium is refracted away from the normal. - However, whether light is from a less dense medium to a denser medium, or vice versa, refraction will not occur if it strikes the surface at right angles as shown in figure (c) below. 4. Identify the real and apparent depths of an object under water. Note: light from point D is refracted away from the normal at the water surface. Light reaching the observer appears to come from point B, which is directly above point D. the object D appears to be in position B. thus RB is its apparent depth. The true or real depth is RD since the coin has not been raised. The apparent depths are always less than the real depths of the object. 5.Explain the application of reflection and refraction. - Reflection is applied in: (i) Searchlights Mwanza Matthews Page 31 of 53  (ii) Headlamps (iii) Magnifying mirrors Refraction is applied in lenses of instruments such as camera, binoculars, telescope, spectacles and microscope. COMPOSITION OF AIR 1. Identify the components of air. The components of air are: nitrogen, carbon dioxide, oxygen and water vapour. 2. Investigate the proportion of each substance in air. - This can be done by first investigating the proportion of oxygen in air as explained below: - Fix the candle firmly to the bottom of a dry trough and place enough water in the trough to cover the lower half of the candle. Light the candle and while the candle is burning, cover it with a dry gas jar. The experiment is set as shown in (a) below. It is observed that as the candle burns, the level of the water in the gas cylinder rises until the candle goes out. The water rises to replace the air that has been used during burning (combustion). The water rises to a level of about one fifth (21%) of the height of the gas cylinder. This shows that oxygen is the gas that supports combustion and that it makes about 21% of the air in the atmosphere. In the experiment, the water did not fill the whole jar as seen in (b) because some air was not used in burning. We call this the (inactive) part of the air which is a mixture of several gases, the main one being nitrogen occupying approximately four fifth 78% of the volume of air around us. Air also contains carbon dioxide and water vapour which occur in very small amounts (1%) 3. Describe the nature of each substance in air (i) Nature of Nitrogen - It is colorless - It is odourless (has no smell) Mwanza Matthews Page 32 of 53  - It is slightly soluble in water - It has almost the same density as that of air (ii) Nature of Oxygen - It is colorless - It is odourless - It is slightly soluble in water (100cm3 of water contains about 4cm3 of oxygen - Its density is approximately the same as that of air (iii) Nature of carbon dioxide - It is colorless - It is soluble in water - It is denser than air - It is odourless (iv) Nature of hydrogen Hydrogen is the lightest, simplest and most abundant element in the universe, which does not normally exist as a free gas but present in compounds, such as water, ammonia and ammonium compounds, for example, in artificial fertilizers. Hydrogen however has the following properties: - It is colorless - It is odourless - It is less dense than air 4. Describe the uses of each substance in air (a) Uses of Nitrogen - It provides a non-reactive (inert) environment, for example,  Inside an incandescent (ordinary) light bulb to prevent the filament from reacting with oxygen in air.  To protect historical documents by preventing paper and ink from reacting with oxygen in air. This stops the document decomposing (rotting).  It is used to freeze materials and keep things cold during transportation.  It is used in the preparation of ammonia when it is made to react with hydrogen  It is an important element that is found in fertilizers such as ammonium nitrate. Mwanza Matthews Page 33 of 53   Plants with nodules containing bacteria such as legumes can convert nitrogen into nitrates thereby enriching the soil for good plant growth. (b) Uses of Oxygen. The uses of oxygen will be classified into medical industrial and others. (i) Medical uses of oxygen  It is used in incubators for premature babies  It is used in ventilators for patients on life support system  Oxygen therapy is used to treat some infections, diseases and disorders  Oxygen supplementation increases the oxygen levels in patient’s blood (ii) Industrial Uses Of Oxygen  It is used in oxy-acetylene flames for welding and cutting of metals  It is used for manufacturing steel from iron by oxidizing impurities such as carbon, sculpture and phosphorous which are found in iron. The steel is then pure.  It is important in combustion process such as the motor car engine and rocket fuel in which it is mixed with the fuel  It is used in the purification of water  It is used in the chemical industry for the manufacturer of some chemical compounds. (iii) Other Uses Of Oxygen  It is used by both animals and plants to produce energy during aerobic respiration  It is used by deep sea divers and mountain climbers to assist them in breathing (c) Uses of Carbon dioxide  It is used in fire extinguishers, this is because it does not support combustion, and it is non- flammable and is denser than air.  It is used to make carbonated (fizzy) drinks.  It is used as a refrigerant because it can be made into a white solid (dry ice). Mwanza Matthews Page 34 of 53   It is used in bakeries where it is produced through fermentation thereby causing the dough to rise as the gas begins to escape.  It is used by green plants for the process of photosynthesis. (d) Uses of Hydrogen  It is used in the production of ammonia  It is used for removing impurities in refining petrol  It is used in extracting metals such as iron from oxide ores  It is used in the production of fertilizers such as ammonia compounds  It is used for hardening vegetable oils, changing them into solid saturated facts such as margarine. GRADE 9 THE HUMAN BODY SUB-TOPIC: CIRCULATORY SYSTEM 1. Describe the blood circulatory system? ANS The blood circulatory system involves the movement of blood in vessels around the body. It involves the heart, blood, blood vessels and lungs 2. Identify the components of blood and their functions? Mwanza Matthews Page 35 of 53  ANS - Red blood cells - White blood cells - Platelets - Blood plasma FUNCTIONS - Red blood cells: transport oxygen and carbon dioxide - White blood cells: fight diseases - Platelets: for blood clotting - Plasma: transports water, body wastes, food nutrients (glucose, amino acids, lipids) 3. Describe the internal structure of the heart. ANS to head and body to lungs pulmonary aorta artery from head and body semi-lunar valve pulmonary vein vena cava from lungs right left atrium atrium tricuspid valve bicuspid valve right left valve tendons ventricle ventricle muscle The heart consists of 4 chambers,the left Atrium and the right atrium(plural:atria) at the top and the left ventricle and the right ventricle below.Ventricles have thick muscular walls because they pump blood at high pressure. Left atrium-receives oxygenated blood from the lungs through the pulmonary vein. Right atrium-receives deoxygenated blood from the rest of the body through the vena cava. Left ventricle-Pumps blood to all parts of the body through the aorta. Right ventricle-Pumps blood to the lungs through the pulmonary artery. Mwanza Matthews Page 36 of 53 Bicuspid valve-prevents back flow of blood from the left atrium. Tricuspid valves-prevents back flow of blood to the right atrium. Semilunar valves-prevents the back flow of blood. 4. Illustrate the movement of blood in the double circulatory system. ANS A. Pulmonary circulation. The pulmonary circulation involves the pumping of blood from the heart to the lungs and back from the lungs to the heart. Heart—>Lungs—>Heart. B. Systemic circulation In this circulatory system, blood is pumped from the heart to the rest of the body and back to the heart. Body—>Heart—>Body. 5. Identify the role of the heart, lungs and blood vessel in blood circulation? ANS The heart pump blood to all parts of the body The valves prevent back flow of blood. The lungs add oxygen to the blood and remove carbon dioxide from the blood. (it is where gaseous exchange take place). Arteries carry blood from the heart to the body while veins take blood to the heart. All veins transport deoxygenated blood back to the heart except the pulmonary vein. Mwanza Matthews Page 37 of 53  All arteries transport oxygenated blood to all parts of the body except the pulmonary artery. RESPIRATORY SYSTEM 1. Identify organs of the respiratory system of a human being? nasal cavity tongue epiglottis trachea bronchus ribs ribs intercostal muscle bronchiole heart alvioli diaphragm Mouth,nose,trachea,bronchi,bronchiole,lungs (air sacs),ribs,diaphragm,inter-costal muscles. 2. Explain the functions of the organs of the respiratory system? ANS Mouth:it is used for breathing when the nose is blocked due to flu. Nose: has two nostrils through which the air from outside is allowed to pass into the lungs. The nostrils contain small hairs which help trap the dust particles from air before it enters the lungs. Trachea:it acts as a passage for air and has cilia and mucus that trap dust.It is a cylindrical tube lined with rings of cartilage to prevent collapsing. Bronchi:directs air to the lungs. Lungs: this is where gaseous exchange take place. Ribs: give physical protection of the lungs. Mwanza Matthews Page 38 of 53  Diaphragm: is a tough sheet of muscles that separates the chest cavity from the abdominal cavity. Air sacs: it is the site for gaseous exchange (make up the lungs). 3. Demonstrate the mechanism of ventilation in a human being? ANS Mechanism of ventilation (breathing) involves two processes. 1. Inhalation / inspiration - Diaphragm muscles contract and flattens - External intercostal muscles contract - Ribs move upwards and outwards - Volume of chest cavity increases. - Lungs inflate - air is drawn inside. 2. Exhalation / expiration - Diaphragm relax and moves upward (becomes dome shaped) - External inter-costal muscles relax - Ribs move downwards and inwards. - Volume of chest cavity decreases. - Lungs deflate - Air is drawn outside 4. Describe the exchange of oxygen and carbon dioxide in the lungs? ANS Oxygen diffuses into the blood stream and carbon dioxide into the lungs from the blood. Mwanza Matthews Page 39 of 53  air in bronchiole oxygenated blood deoxygenated bloo alvioli 5. Explain tissue respiration? ANS Tissue respiration or cellular respiration is a chemical process in cells by which energy is released from food (glucose).Glucose combines with oxygen to release carbon dioxide,water and energy. WORD EQUATION Glucose +oxygen ->Carbon dioxide +water+Energy 6. Explain the effect of cigarette smoking on the respiratory system? ANS Causes, - Lung cancer - Bronchitis - Stomach ulcers - Bladder cancer - Osteoporosis (brittleness of the bones) HEALTH SEXUALLY TRANSMITTED INFECTIONS Mwanza Matthews Page 40 of 53  1. Identify the common sexually transmitted infections? ANS HIV and AIDS, Syphilis, Gonorrhea,Genital Warts. 2. Explain transmission of Sexually Transmitted Infections. Sexually transmitted infections are transmitted through - Unprotected sex - Blood transfusion with contaminated blood - Having multiple sexual partners 3. Describe the prevention of STIs? - Correct and consistence of condom use - Stick to one faithful partner - Avoid casual sex - Abstinence from sex. - Avoid sharing sharp instruments, i.e. needles,razor blades. 4. Explain the impact of HIV and AIDS on the population? - Brings poverty - Increase of orphans - Pressure of health services Mwanza Matthews Page 41 of 53 THE ENVIRONMENT CYCLES IN THE BIOSPHERE 1. Describe what Oxygen and Carbon cycle are? - Oxygen cycle is the circulation of oxygen in the atmosphere - Carbon dioxide is the circulation of carbon dioxide in the atmosphere - Carbon dioxide and oxygen cycles are balanced by respiration and photosynthesis. - Carbon dioxide is removed in the atmosphere by photosynthesis and it is added by respiration - Oxygen is added to the atmosphere by photosynthesis and is removed from the atmosphere by respiration. 2. Identify factors affecting Oxygen and Carbon cycle? - Plants take in carbon dioxide during photosynthesis and give off oxygen. - Animals take in oxygen and give off carbon dioxide during respiration 3. Describe the nitrogen cycle? - Lightening converts nitrogen in the atmosphere to nitrates - Nitrogen fixing bacteria convert free nitrogen to nitrates in the soil. (fix nitrogen in the soil) - Legume plants e.g. beans increase the amount of nitrogen in the soil. - Nitrogen rich fertilizers increase the amount of nitrogen in the soil. 4. Explain the natural balance of gases in the atmosphere. - Oxygen 21% - Nitrogen 78% - Carbon dioxide 0.03% - Other inert gases 0.97% - WATER MANAGEMENT 1. Describe the importance of water management in our daily life. - Generating electricity - Irrigation - washing and cleaning - mixing chemicals - cooking food 2. Describe effective water management system. - Construction of dams - Water reservoirs - Purification of water, involves the following process - Screening - Sedimentation Mwanza Matthews Page 42 of 53  - Filtration - Disinfection(chlorination) PLANTS AND ANIMALS CONSERVATION OF ANIMALS AND PLANTS 1. Explain the importance of domesticating animals and plants. PLANTS - Are a source of food - Provide building materials like poles and timber - Some plants are medical hence used to cure certain diseases. - Provide beauty and shade at home - Control soil erosion by covering the ground - Provide manure and biogas - Some plants with nice flowers may provide income when flowers are sold. ANIMALS - Major source of protein (food) - Animal products such as hinds and skins are important in making leather products - Animals are kept as pets to beautify the homes - Some animals like dogs are kept for protection purposes - Some for recreation e.g. animals in national parks and zoos - Some animals used as dowry during marriage. - Some animals are used for transport and cultivation. 2. Explain ways of improving domestic breeds of animals and plants. - By crossing animals and plants that have desirable characteristics to produce off- springs with desirable characteristics - In plants by cross pollination(transfer of pollen grains from the anthers of one plant to the stigma of another plant) 3. Identify animals and plants threatened by extinction. ANIMALS Wild dogs, black rhino, antelopes, honey badger, elephants, crocodiles. PLANTS Mutondo, mukwa and mukula 4. Describe the importance of protecting endangered animals and plants. - Source of food, medicines and industrial raw material - For income Mwanza Matthews Page 43 of 53  - Foreign currency from tourists - Plants reduce soil erosion - For future generation - For aesthetic / beauty - Plants produce oxygen for photosynthesis. 5. Explain methods of protecting endangered animals and plants. - Use of appropriate farming practices such as crop rotation - Game cropping - Setting up of conservation education programmes in the curriculum - Controlling burning of charcoal - Creation of game management area, forest reserves and game parks PHOTOSYNTHESIS 1. Identify the conditions necessary for photosynthesis. -sunlight, carbon dioxide, water and chlorophyll 2. Identify the products of photosynthesis in a leaf. Glucose (sugar) and oxygen 3. Relate the process of photosynthesis to respiration -Photosynthesis occurs only in green plants while respiration occurs in both plants and animals. -Photosynthesis produces sugar by use of energy while respiration burns sugar to release energy. -photosynthesis stores energy while respiration releases energy. -photosynthesis uses water while respiration produces water. -photosynthesis uses carbondioxide from air which is released by animals and human beings during the process of respiration while respiration releases carbon dioxide which is used by plants to make food during the day. -photosynthesis produces oxygen which is used by animals and human beings for breathing in while respiration uses oxygen from air which is released by plants during the process of photosynthesis. -photosynthesis takes place during the day while respiration takes place both during the day and at night. TRANSPIRATION Mwanza Matthews Page 44 of 53  1. Describe the process of transpiration? Transpiration is the loss of water-vapour by plants through the leaves (stomata) 2. Investigate the factors that affect the rate of transpiration? - Deforestation completely removal of vegetation - Light intensity: light intensity influences stomata opening - Humidity: the amount of water-vapour in the atmosphere - Temperature: high temperature increases the rate of transpiration while low temperature reduces the rate of transpiration because water will take long to turn into vapour wind. Structural factors - Stomata - Cuticle - Leaf size and leaf shape upper epidermis chloroplasts palisade cells vacuole cytoplasm air spaces spongy leaf vein layer 3. Explain the importance of transpiration in plants? It helps in transportation of water and materials from roots to the upper part of the plant. MATERIALS AND ENERGY Mwanza Matthews Page 45 of 53 CHEMICAL REACTION 1. Describe what chemical reaction is? A chemical reaction is one where a new chemical substance is formed from the original substance. 2. Describe the nature of chemical reactions? - During exothermic reaction heat is evolved (given out) to the surroundings - During exothermic reaction heat is absorbed from the surroundings. 3. Classify different types of chemical reactions?Synthesis.Decomposition.Single replacement.Double replacement. 4. Describe the chemical reactions. - Synthesis: is the combination of two or more elements to form a compound. e.g. iron combines with sulphur to form iron sulphide iron + suphur iron (ll) sulphide - Decomposition: is the breaking down ofa single compound into two or more simpler substances e.g. heating copper (ll) carbonate beaks it to copper (ll) oxide and carbon dioxide. Copper (ll) carbonate copper (ll) oxide + carbon dioxide - Single replacement: is a type of a chemical reaction where an element reacts with a compound and takes the place of another element in that compound. e.g. AB +CA+BC. Chloride +Potassium iodidePotassium chloride +Iodine - Double replacement: during a double replacement reaction atoms or irons from two different compound replace each other e.g. AB + CD  AB +CB Barium nitrate + sodium sulphateBarium sulphate +Sodium nitrate. 4. Demonstrate the chemical reaction of water with electricity? The electrolysis of acidified water (dilute sulphuric acid) is an example of a decomposition reaction. When a direct current is passed through the acidified water (H2O), it decomposes into its components which are oxygen (O2 ) and hydrogen (H2) (twice as much hydrogen as oxygen) by means of an electric current. 5. Explain the law of conservation of matter? The total mass of substances before a chemical reaction is equal to the total mass of the substances that are produced. LIGHT AND ITS NATURE Mwanza Matthews Page 46 of 53  1. Describe the different types of lenses? - A Converging lens is also known as a convex lens. It is thicker in the middle and thinner at the edges. It makes parallel light rays passing through it to bend inwards and meet (converge) at a point. Converging lens Concave lens - A concave lens is also known as a diverging lens, is thicker at the edges and thinner in the middle. This lens makes a beam of parallel light rays passing through it to diverge (or bend as it spreads outwards) from a point. 2. Demonstrate the location of the focal point and focal length of a lens? - The distance between the focal point and the centre of the lens ( or focus of the lens ) is called the focal length. - The principal focus or focal point is the point at which rays parallel to the principal axis either converge or appear to be diverging after refraction or reflection through the lens. 3. Explain the mechanism of a converging lens to produce real and virtue images? 4. - A real image is the image formed where the light rays are focused. Real images occur when objects are placed outside the focal length of a converging lens or outside the focal length of a converging mirror. 5. - A virtual image is formed at a location from where light rays appear to have converged. Converging lenses form virtue images if the object distance is shorter than the focal length. 6. Explain the uses of converging and diverging lenses? -Converging and diverging lenses are used in a microscope, a magnifying glass, camera, film projector and spectacles. 7. Demonstrate the production of a spectrum from white light? - A spectrum (plural: spectra) is a complete range of colours as seen in a rainbow into which white light can be separated when it passes through a prism. 8. Demonstrate the combination of colours of the spectrum to produce white light? - A second triangular prism can used to combine the different colours of the spectrum to form white light again. The second prism, of the same size as the first one, is placed in an inverted or reversed order. Mwanza Matthews Page 47 of 53  9. Describe the production of a rainbow? - A rainbow is a group of almost circular arcs of colours, all having a common centre. Rainbows are formed from refraction of sunlight rays as they enter failing droplets of water suspended in the atmosphere and the refraction of light from the back of the droplet. 10. Explain why sunsets and sunrise appear red. - Sunsets and sunrise appear red because the red light which a longer wavelength and much stronger penetrating power, easily passes through this larger distance and dust particle, thus the sky appears red to our eyes at sunset and sunrise. COLOUR FILTERS 1. Explain that colours of an object depend on the colour of light it reflects? - The colour of an object depends on the source of the light and the light it reflects. 2. Describe the effects of colour filters on light rays. - A filter absorbs or reflects other colour light and only transmits the colour of the filter. ELECTRIC CURRENT AND VOLTAGE IN CIRCUIT 1. Explain the difference between electric current and voltage. ANS Electric current is the rate of electrical charged particles. While voltage is an electromotive force or potential difference expressed in volts / potential difference is work done in moving the electric charge from one point to another. 2. Demonstrate the use of an ammeter to measure electric currents in a circuit. ANS An ammeter is an instrument used to measure the electric current flowing in a circuit. The ammeter in a circuit in connected in series in order to measure the current flowing through a component in a circuit. 3. Demonstrate how to measure potential difference in a circuit. - Voltage is measured in volts using an instrument called voltmeter. The symbol for volts is. A voltmeter is connected in parallel across the components to measure in a circuit. The number of cells affects the voltage across them. The more the number of cells the higher the voltage. 4. Describe the relationship between potential difference and current. - The relationship is ohms law which states that the current (l) flowing through a metal wire is directly proportional to voltage (v) (provided the temperature remains constant). 5. Explain the use of electric current in the local environment. - Lighting in lamps - Heating in electric irons - Heating kettles Mwanza Matthews Page 48 of 53  - Cooking and electric cookers PRESSURE 1. State what pressure is? - Pressure is the amount of force acting per unit area of a surface. Pressure = force measured in N/M 2. Identify factors affecting pressure in gases? - Factors affecting pressure are temperature, amount of the gas and volume. ENERGY AND ITS CONSERVATION 1. Explain what energy is? - Energy is the ability to do work 2. Identify different forms of energy? - Potential energy - Kinetic energy - Chemical energy - Electric energy - Heat energy 3. Describe how different forms of energy can be changed? - Combustion of fuels in motor vehicles, with the help of electric energy from a battery, results in the conversions of chemical energy into kinetic, heat and light energy. In the electric storage battery, chemical energy is converted to electrical energy and later converted to light and sound energy. 4. Explain the law of energy conservation? - Energy is neither created nor destroyed, although it may be converted from one form to another. 5. Explain the effects of energy production on the environment? - Depletion of resources - Damage to natural geothermal features. - Global warming and climate change. - Water pollution. - Air pollution. - Land degradation. - Wildlife and habitats loss. 6. Explain ways of conserving energy? - Replacing light bulbs with fluorescent bulbs or LED bulbs. Mwanza Matthews Page 49 of 53  - Reducing the use of outdoor lights for security purposes. - Switching off all electrical appliances and lighting equipment - Using natural light from the sun to brighten homes. - Reducing excessive heating and cooling in summer and winter respectively in homes with summer cooling and winter heating systems. - Conserving fuels. - Higher use of renewable energy sources. - Practice the 3Rs (reduce, reuse and recycle) - Working in with others. COMMUNICATION 1. Identify ways of sending and receiving information over long distances. - Communication can be sent or received by the use of telephones, radios, television and emails 2. Describe the advantages and disadvantages of the different ways of sending messages? Advantages TELEPHONE This is the most popular method of sending information that has been existing in different Forms for the past years in both homes and business contacts. However mobile phones Are now the preferred methods of communication. Mobile phones are also known as A cellular phone is a phone that can make and receive telephone calls while moving Around a wide geographical area. It is a hand held device and is a fast way of sending Regardless of where you are. Advantages - It provides for two-way communication and one on one communication. You get immediate feedback during the communication. - Telephones provide current and timely information. - The conversation is relatively private between the people communicating. Disadvantages - Telephones are expensive to buy and to install. - The person must be within the premises or available to pick up a telephone call. If they are not available, communication will not take place. - The use of telephones and mobile phones requires a certain amount of literacy. Mwanza Matthews Page 50 of 53 RADIO For a very long time, radio has been the fastest and most technologically advanced means of transmitting information. Radio communication involves the converting of sounds into electrical signals known as audio signal. Advantages - It is the cheapest form of media in terms of energy use, weight and cost. - People can listen to radio in the background while doing other work, for example, while driving to and from work. - It has the ability to reach specific audience through specialized programming. That way, it is possible to have radio stations using local languages so the listeners can easily understand the message. Disadvantages - Radio allows only one way communication. The sender can only send information but in most cases there is no feedback. - Radios can only send radio signals without visual signals. - Radio signals are susceptible to interference so it can sometimes be hard to receive a clear signal. TELEVISION Television is one of the popular ways of sending information around the world Nowadays. It is very effective because it combines both audio and video signals. Advantages - Television is able to combine both sound and pictures thus making the communication process more effective. - It has a wide geographical coverage and broad audience. - Television keeps the audience well informed of current affairs and breaking news around the world. Disadvantages - It is an expensive method of communication. Buying a television for example, can be very expensive. - The programmes are not aired at a convenient time for the viewer. - Unlike the radio, one cannot watch television while doing something else, such as driving since it requires the full attention of the viewer. EMAIL Mwanza Matthews Page 51 of 53  E mail stands for electronic mail. It enables a person to send well arranged text files and pictures to another person’s e- mail address. Advantages - Emails are fast. They are delivered at once around the world. No other form of written communication is as fast as the email. - Aside from the cost of internet connections, email is free. One can send as many messages, files, videos, documents and presentations as he or she wants without having to pay anything. - Thousands of email messages can be archived into folders on your computer or handheld communication device such as a cell phone to be retrieved when you need them. Disadvantages - Emails can carry viruses which can affect the computer systems. They can read your email address book and send themselves to a number of people around the world. - Many people send unwanted emails to others. It could take a lot of time to them out and sometimes important messages get lost in the many unsolicited emails. - Sending an email requires both the sender and the recipient to have email addresses and access to the internet or computer. 3. Describe the transmission of radio and television signals? - Radio and television signals broadcast is the primary means by which information and entertainment reach the public in virtually every country or nation around the world. 4. Explain the amplification of sound? - Amplify sound is to increase the strength of an electric signal by means of an amplifier. 5. Explain the difference between digital and analogue transmission information? - Analogue transmission conveys voice, data image, signal, or video information using an information signal that is continuously varying while digital transmission is the transmission of signals in a form of a stream of binary numbers (combinations of zeros and ones). A digital signal uses discrete (discontinuous) values. 6. Explain the use of satellite in long distance communication? - A communication satellite is an artificial body or spacecraft placed in geostationary or synchronous orbits around the earth or moon or another planet in order to collect and transmit information or for communication. It also sends signals from radio, television, telephone. In satellite Mwanza Matthews Page 52 of 53  communication, communications satellite receives signals from different stations on the ground called Earth Stations or Ground Stations. 7. Describe the transmission of a live broadcast of an event from Africa to Europe using raw block diagrams? ANSWER Live football match Sound and video actions Small transmitter on at heroes stadium in recorded by microphone and mobile television van Lusaka camera respectively (TV) Satellite above Earth station at Mwembeshi in Powerful transmitters at Indian ocean pick up Zambia picks up the signal and BBC main studio station the signals and transmit them picks up signals and sends transmits them them Earth station in Main transmitter in Paris picks Televisions transmitters at Paris, Europe picks up the signals and transmit them televisions stations in Paris up the signals and picks up signals and transmits them transmits them Transmitter in Repeater stations picks up the Main transmitter in Paris provincial signals and transmit them picks up signals and headquarters picks transmits them up signals and transmits them Television (TV) set Viewer watches a live match in a home picks up football match the signal Mwanza Matthews Page 53 of 53