Exploring Science Active Book 88L Sound and Hearinga. Animal sounds Uses Communicate Remind danger Find mate Hunt Stop intruderb. Sound device How sound travels Vibrating (moving back and fro) objects produce sounds How tuning fork produces sound Variation in air pressure Collision between air particles Complete to and fro movement sound wave move away from the fork Reminders: Cycle per second = number of waves generated per second Increase in cycles per second higher speed E.g. travelling in oil and in waterc. Music to your ears Ways to detect Microphone connected to an oscilloscope Sound intensity meter Terms used in sounds Frequency No. of complete waves passing a point per second Unit : Hertz (Hz) 20000 Hz20 HzAudible Range

Wavelength Distance between same point on two cycles

Wavelength is inversely proportional to frequency Amplitude = loudness Reminder : higher pitch louderd. Light and sound Similarity Wave Reflection Refraction -- focusing Transfer energy Difference Sound: requires a medium, travels slower (334 ms-1), faster in solid than gas or liquid because. Light : does not require a medium, travel faster, (3x108 ms-1), faster in air than solid or liquid Use for communication

e. How do we hear sound Sound approaches Eardrum (vibrate) Three tiny bones (vibrate) Cochlea (conversion) Auditory nerve (transmission) Brain (interpretation) Reminder: make a louder sound by using trumpet tube Ear damage Blocked by wax Cure by washing out the wax Damage to eardrum due to loud sound Repair itself Infection to middle ear Antibiotics Tiny bones fused due to aging less sensitive to vibration Nerve does not work well Permanent damage to cochlea due to persistent loud noise How dolphin talk Clicks from nasal sacs Echolocation Reflected waves (echo) being focused by the fats to the inner earf. Use of sounds Unwanted noise Need sound insulators dont pass the vibrations to other particles Sound intensity meter Threshold hearing to human

Uses of ultrasound Flaws check Ocean depth Communication Echolocation

Exploring Science Active Book 88K Lighta. What a picture! Cameras Bitumen Chemical cameras Digital cameras Communication Space explorations Travelling light Luminous: light creating Light spreads out and some of them goes into our eyes Non Luminous Seen because light bounces off them (is reflected) and enters our eyes Ray diagram Speed of light Fastest things in the universe Measurable Observing difference in time of successive moon eclipses Lanterns but failed Properties of light Travel in straight lines Shadows Because light cannot travel through or bend around opaque objects Scattering By comparatively large molecules

Reflection Refraction

b. Cameras and eyes Nature of objects Transparent Translucent a glow of lightShadows

Opaque light cannot pass through (absorbed) Light energy Heat energy Selection of materials for heat conduction Camera Verse EyesPinhole CameraEyes

Entry of light Brightness or protectionPinhole in the frontPupil

FocusingLens / NoneLens

Image formationScreenRetina Easily damaged by strong light

Image detectionChemicals or sensorsRods and cones and brain

Differences Energy change Retina converts light to electrical signals Existence of optical nerve Pass the impulses to the brain Brain allows you to see the image

c. Mirror image Reflection Regular reflection clear and sharp images Irregular reflection (Scattering) blurred images Reminder: this scattering is different from that mentioned in (a) Plane Mirror: glass coated with silver or aluminium on the back (Also mercury) Laws of reflection on a plane mirror Angle of incidence Angle of reflection Reflection occurs at the surface of the mirror Properties of the image formed Same size Laterally inverted Object and image are of same distance from the mirror Virtual

HSW: Periscope

d. Lens and Light Use of lens Refract the light (bending) to make the image sharp and clear Refraction When light travels from one transparent substance to another Take place at the interface If incidented at 90o no change in direction If one medium is optically denser Light travelling from the less dense one to it bends towards normal Light travels slower in dense materials

Image appears closer and bigger for above case Lens Converging lens Focus light to one point Fatter bend more closer focus HSW : Magnified or diminished images Microscope Diverging lens Diverge the light Focus located on the side of the object HSW : Diminished image

e. Making rainbows Dispersion of white light White light is composed of different colors Split up with a prism A band of colors spectrum Separation of colors dispersion E.g. Rainbow is formed by refraction of light rays by rain or mist Aberration () in lens but solved by a combination of lenses

Absorption and Transmission Coloured object because they do not reflect all the colours White Black 3 primary colours Red, Green, Blue Shining a coloured light colour subtraction

Exploring Science Active Book 88I Heat Transfersa. Hot stuff Heat and temperature Heat a form of energy (thermal energy) Unit: Joules (J) **Depends on: temperature, material, mass Flow from a hot object to a cool one until same temp. Greater temp. difference faster rate of heat transfer Temperature how or cold an object is Unit: Degree Celsius (oC) Difference Temp. can be measured but heat cannot.

b. Heating solids Conductors & Insulator Conductors Heat is quickly conducted away feel cold Insulators E.g. Carpets, jackets Air trapped (Insulator) keep warmth Model of conduction1. Particles at the hot end gains energy and vibrates more2. Collision between particles passes the energy on Conduction best in solid, then liquid, then gas Because the closer the particles, the easier is the collision

Effect of heating up Particles move faster The solid expands and the density decreases If cooled solid contracts and the density increases

c. Heating fluids Convection model1. When the air near the fire is heated, the particles spread further apart

2. The air becomes less dense and rises 3. It meets cooler air and passes the energy on. 4. It cools and becomes denser. The denser air sinks, setting up a cycle or convection current.

E.g. sea breeze, land breeze, shape of a fire

d. Changing state Temperature curve

Melting point, freezing point, boiling point, condensation point Change of states Temp. stays constant when the substance changes from one state to another Stepping up requires energy; stepping down releases energy

Evaporation Sweating for cooling Absorb heat from your body

Dogs dont sweat but pant to cool themselves Warmer air from the lungs evaporates the water on their tongue Breathable jackets They let the water vapour out that you will sweat less less heat is lost to the evaporation of sweat keep you warm and dry

e. Radiation Similarity with light Does not require a medium for travel E.g. all radiation from the sun travels through the empty space Can pass through transparent objects Can be focused using a magnifying glass

Heat transfer Emitted by hot things Easily absorbed by dark objects; but easily reflected by shiny materials

Use of IR Thermal imaging Measure IR and convert the data into maps of temps. Uses: Provide sight at night Weather forecasting

Exploring Science Active Book 88A Food, glorious food!a. On a diet (Keywords: Nutrients, Food labels, Food tests)i. Types of nutrients CarbohydratesEnergy

FatsGrowth & Repair

Proteins VitaminsKeep Body Healthy

MineralsAssist peristalsis

Fibre Water Carry dissolved chemicals around Maintain shape of the cells Maintain body temperature

ii. Main use of food Energy Growth and repair Health

iii. Food tests Iodine test Starch If present, Brown Blue Black Biuret test Protein If present, Blue Purple Transparent test Fat If present, a greasy mark Benedicts test Glucose If present, Green, Yellow and Red colours are seen Test for sucrose Hydrochloric acid + boiling cool down sodium hydrogen carbonate solution Benedicts test If present, Green, Yellow and Red colours are seen.

b. Balanced diet (Keywords: energy requirement, e Contain a wide variety of foods Food pyramid

NutrientsExamplesWhy its neededGood sources

CarbohydrateStarch, sugars1. Energy sourceN.B. If excess fatPasta, Cereal food, Fruits, Sweets

Fat1. Energy source2. Keep warmMeat, oil

Protein1. Growth & RepairMeat, beans

VitaminsVitamin C1. Help cells in tissues to stick together properlyVitamin C: fruit and vegetables

MineralsCalcium, Iron1. Calcium: health of bones2. Iron: make red blood cells1. Calcium: milk2. Iron: spinach

Fibre1. Keep intestine clean2. Prevent constipationVegetables, fruit, wholemeal bread

Water1. Solvent2. Maintain shape of the cells3. Maintain body temp.

Health Problems due to Diet Too much fats heart disease fat blocks the supply of blood to the heart muscles die and cause chest pain cancer obesity Too little proteins Kwashiorkor (big tummy) Too little food Weak and tired Kwashiorkor ()

Variety of Diet Different people require different calories per day Girl < Boy Factory worker < Office lady Woman < Pregnant woman

VS

VS

c. Youve got guts Process of digestionIngestionDigestive Juice:Saliva Produced by salivary glands Breaks down starch into sugar (by amylase) Makes food moist easy to swallowTeeth Grind the food into smaller pieceSwallowing: Muscles in gullet contracts to push the food downStomachDigestive Juice: Food is churned up with strong acid (pH 1-2) Pepsin (an enzyme)Break down proteins into amino acidsSmall intestineDigestive juice in small intestine: pH > 7 Pancreatic amylase starch sugar Lipase fat fatty acid Large food molecules small molecules wall of small intestine blood stream (absorption)

EgestionNo digestive juice in large intestine Fibre is not digested Some animals can use bacteria to digest fiberOnly water can be removed faeces stored in rectum anus

Appendix

Why digestion Large insoluble food molecules are broken by enzymes into smaller soluble molecules small enough that can pass through the wall

Enzyme: Break large molecules into smaller ones Do not get used up at the end of breaking Only works on one particular type of molecule E.g. amylase starch; proteases proteins; lipase fat Very sensitive to pH and temp. E.g. salivary amylase stop working after entering the stomach (acidic) Model: Visking tubing A tubing with very small holes on it Only small and soluble molecules can pass through

Water, glucose

After some time, the right side will be full of glucoseWater, starch, amylase

The insoluble large starch molecules are broken down by amylase into smaller glucose molecules so can pass through the wall of intestine and be absorbed The model only works best at body temperature because the enzyme (amylase) works best at 37oC. Similar applies to pHd. In the blood (absorption) Intestinal wall Villi Thin wallGreatly increases the surface area for absorption rate

Microvilli Blood capillaries Join up to a vein liver Liver: remove poison and store excess nutrients and then pump around the body by the heart The whole process is assisted by the blood circulating system

Tissues When the capillary reaches the tissue, food leaks out to form tissue fluid, carrying the dissolved food to cells Respiration Some of glucose in the tissue is used to release energy Glucose + Oxygen Carbon dioxide + Water + Energy Energy is used as: Heat Keep warm Muscular work Energy to form cells Growth and repair

Exploring Science Active Book 88B Going for Golda. Energy for life Respiration Require glucose Glucose is provided by the digestion of the carbohydrates E.g. athletes glucose supplement Boyles experiment Air is needed for our body Mayows experiment Certain part of the air is needed to keep a candle alight and a mouse alive Word equation glucose + oxygen carbon dioxide + water (+ Energy)ProductReactant

b. Round and round Digested carbohydrates (sugars) are absorbed by the small intestine; oxygen is absorbed by the lungs Cells need glucose and oxygen to release energy The reactants are brought to the cells through circulatory system Capillaries: tiny tube with very small holes in the walls Small molecules can get out easily as tissue fluid Arteries carry blood away from the heart Vein carry blood to the heart Circulating process1. When the heart muscles contract, the deoxygenated blood in the left chamber is pumped through the pulmonary artery to the lung while the oxygenated blood is pumped through the aorta and then the capillaries to the cells for release of energy. Plasma containing dissolved oxygen and glucose leaks out, forming the tissue fluid Red blood cell cannot leak out.2. Deoxygenated blood reaches lung and is oxygenated inside the alveoli.3. When the heart muscles relax, the oxygenated blood in the lung flows back through the pulmonary vein into the right chamber while the deoxygenated blood from the cells flow through into the left chamber through a vein.4. The contraction and relaxation process repeats again and again.

c. Into thin air Effect of aerobic exercise Heartbeat and breathing rate increases to get enough oxygen to your cells for respiration. If too little oxygen weak and tired Diseases related to respiration Emphysema Cannot take enough oxygen from the air Have shortness of breath even when resting Tiredness Frostbite Blood vessels narrow when it is cold If not enough oxygen is got, cells die because of lack of energy Heart attack Blood vessels supplying oxygen to the heart muscles are blocked by fat not enough oxygen for the muscle cells to be alive Treatment: beta blocker Slow the heart down less glucose and oxygen is needed for the heart muscles less likely to die Mountaineers should not take beta blocker blood vessel is narrowed due to coldness more blood flow to satisfy the oxygen requirement Chemicals affecting respiration Carbon dioxide Product of respiration Harmful if in large amounts So it is carried back to lungs and is excreted Carbon monoxide Stop the red blood cells from carrying oxygen Turn the muscles and red blood cells bright red Used in packaging meat Hydrogen cyanide Stop one of the reaction in aerobic respiration (by inhibiting the working of an enzyme) It can leak into the tissue fluid and kills cells quickly

d. Exchange rates Gaseous exchange in the lungs Respiratory system Breathing Muscles in the lungs change size Inhale lungs biggerVentilation

Exhale lungs smaller Air sacs (alveoli)Carbon dioxide and oxygen can diffuse easily and efficiently into and out of the blood

Large surface area for exchange of gases One cell thick Many surrounding blood capillaries (also thin) Deoxygenated blood (dark red) is oxygenated (bright red)

Cleanness of the respiratory tract Mucus traps dust, dirt and germs Ciliated epithelial cells (trachea and bronchi) sweeps mucus out of lungs and into the gullet swallowed

Effect of cigarette smoking Chemicals and heat Stop cilia working Mucus accumulates in the lungs reduces the surface area for gas exchange Irritate alveoli Break down of alveoli (Emphysema) Reduces surface area Similar effect in breathing in large amount of dust over a long period Remarks: chronic effect of air pollution Questions**

e. Respiration detection Composition of inhaled air and exhaled airInhaled airExhaled air

Nitrogen gas78%78%

Oxygen gas21%16%

Carbon dioxide gas0.03%4%

Water vapourVariable More

TemperatureVariableWarmer

Dirt particlesVariableCleaner

Respiration of aquatic lives From dissolved oxygen Water plants Dissolved oxygen diffuses into the cells

Aquatic animals Gills filter the water

Large surface area and good blood supply Speed up the diffusion Effect of power stations on aquatic lives Water is used for cooling the river water is warmed up But oxygen dissolves less in warmer water suffocation of fish Solution: careful monitoring of water temperature

Detection of carbon dioxide Hydrogencarbonate indicator Normal pink More carbon dioxide yellow Less carbon dioxide purple

Exploring Science Active Book 88D The way of dodoFossils reveal the history of the Eartha. Dead as a dodoi. Animals extinct due to various reasonsii. Organisms are adapted to their habitats. If environment (e.g. temperature) changes, the organisms may not be adapted to the new environment and then die.b. Death of the dinosaursi. Why did dinosaurs become extinct? Volcanoes Emissions like sulphur dioxide and carbon dioxide caused acid rain and global warming Evidence: rocks formed by these huge eruptions in India Meteorite Impact Giant meteorite rocks and dusts covered the Earth, blocking the sunlight coldness kills the dinosaurs. Evidence: Barringer Crater in the USA Evidence: Iridium layer found in liquid rocks and asteroids

Disease Doesnt explain all evidence E.g. why so many sea animals died at the same timeii. Animal kingdom Vertebrates (with backbone) and Invertebrates Dinosaurs with hip bones Saurischia Without hip bones Omithischia Scientists who study fossils: paleontologists

c. Prehistoric plants Evidence from plantsPlants in wet areasPlants in drier regions

Mosses do not have roots Their leaves are thin and lose water quickly Mosses live in wet places

Flowering plants have roots They have cuticle (waxy and waterproof) on their leaves Their stems have xylem vessels (tubes that carry water)

Plants extinction If atmosphere gets too hot lose too much water and die If atmosphere becomes very dark stop photosynthesis and cannot generate food and energyd. Detective work Community = living things in a habitat Population = no. of individuals of one species Method of sampling Take as many samples as possible Quadrat plants Tree beating animals in trees Sweepnet animals in tall grass Tullgren funnel animals in leaves Animals have a behavior that makes them move away from heat and light Those who fall into a beaker can be counted. Pond dipping water organisms Pitfall trap small land animals Working examples

e. Physical environment factors Factors TemperatureCauses changes in communities, populations and distributions

Acidity Water flow Wind speed Tools pH paper anemometer sensors connected to computers record data and send to lab e.g. corals Only live at certain temperature If gets too warm, they turn white and die

f. Focus on: Computer modeling Age of rocks from volcanoes no. of volcanoes on Earth at a particular time. estimate the amount of carbon dioxide added by volcanoes to the air. Air trapped in the polar ice composition of atmosphere Measure the changes in environmental factors make models that can explain changes in the past and predict changes in the future

g. Living factors Animals Mates Food Water Resources for the growth of population

Space Plants Water Light Space Mineral salts E.G. Migration of swallow For warmer area where there is more food Stimulus is the cold weather Living factors are organisms that affect other organisms around them Predator depend on them as food feeding relationships in food web If the prey disappears, the population of predator will decrease sharply If the competitor disappears, its opponents population will increase(Remarks: producers, herbivores, primary / secondary consumer, top predator (Omnivore/ carnivore))

Symbiosis Provide shelters or help to decompose animal waste

h. Pyramids and poisons Pyramids of numbers Energy losses reduce the amount of energy as food chain goes on. Energy losses at each stage population the pyramid can support depends on the energy stored in organisms

Poisons in the food webs Pesticides are used to kill organisms that eat or ruin their pests They may be passed and accumulated along the food chains if they are not destroyed fatal concentration E.g. DDT weakening of bird egg shell

Exploring Science Active Book 88F Materials and recyclingElements, compounds, mixtures recycling from mixtures back to elements to form new compounds

a. Sorted! We classify materials before recycling Classify substance codes Labels E.g. plastics recycling code

b. The material worldi. How were different elements discovered? Needs extraction The time of discovery is related to the easiness of extraction from ores Bronze Age Iron Age Remarks: Copper is extracted by heating certain rocks in charcoal Relationship between reactivity and easiness of extraction

NF: Method of extraction Direct Heating

Heating with carbon

Displacement

Electrolysis

c. Elementary Elements Cannot be split into simpler substances by mixing them or heating them E.g. Lime can be split by electrolysis into calcium and oxygen. Atoms The smallest particle of an element Atoms builds up elements Different atoms mixture instead of elements Diagram

How do we represent different elements

d. Compound interest Compound elements joined together by chemical reactions Molecule discrete form of non-metals in nature Chemical formula (empirical represent the simplest ratio of elements)Dish

E.g. CFC CF2Cl2 E.g. *PVC C2H5Cl E.g.* Polythene CH2 Chemical formula Showing the ratio of different elements Oxide name First word: metal name; Second word: represent the non-metal -ide compound contains two elements; ox- name of non-metal If there are two non-metals to one metal use di- before oxide E.g. carbon dioxide Chemical formula :

E.g. formation of rust iron + oxygen iron oxide HSW: how to speed up rusting

e. Mixtures A mixture is what you get when you put two substances in such a way that no chemical reaction occurs between the components and you can separate them again.

Examples: Eggs vs Doughf. Metal detecting Properties of metals Shiny Flexible Good heat conductors Solids at room temp. Good electrical conductors Some are magnetic e.g. iron

Properties of non-metals Usually gases or liquids at room temp. Melt easily Good heat and electrical insulators Usually brittle

Some examples of non-metals Sulphur Low melting point (m.p.) Brittle Yellow Chlorine Poisonous gas at room temperature Uses: Use with oxygen to bleach recycled paper Kill harmful bacteria in swimming pool Remarks: high concentration of chlorine is harmful

Iodine Poisonous Purple in colour Sublimes upon heating (i.e. changes directly from solid to gas)

g. Re-use, renew and recycle how can 3R be beneficial to both business and environment

Reuse Use the things again without melting them into the simplest formSustainable development because depletion of resources

Recycle Use the waste to make other substances Glass Reused by washing Recycled by crushing up and melting to make new bottles Recycled glass: Bottles Roads Paper Recycled paper envelopes, cardboard and toilet paper Plant trees after chopping them down

Metals Extraction of aluminum Bauxite containing aluminium oxide Electrolysis of aluminium oxide aluminium [at 1500oC] aluminium oxide aluminium + oxygen Aluminium has a lower melting point than aluminium oxide recycling is beneficial No need to extract and use so much bauxite Less waste in landfill Reduce energy cost less energy is used to extract and melt the raw materials Reduce carbon dioxide emissions Plastics Recycling is important to plastics Difficult to reuse plastic bottles they soften or melt at relatively low temp. the source of plastics oil is limited Recycled plastics Black sacks Traffic cones Crates

Fleeces

Exploring Science Active Book 8Particle diagram

Atoms, Elements, Compounds, Mixtures

8G All that glitters

Word equationChemical formulaChemical changePhysical change

a. Difference between elements and compounds Atoms The smallest particles that make up every substance Elements Only one type of atom Compounds Two or more elements Linked by chemical bonds (attraction) The elements cannot be separate easily Particle diagram

b. Some structures in compounds or elementsi. Molecules Natural existing forms of some elements and compounds E.g.SubstanceNumber of atoms joined in a molecule Chemical nameChemical formulaDiagram

Hydrogen 2 HHydrogen

Water2 H and 1 O

Natural gas1 C and 4 HCarbon hydride

Nitric acid1 H ,1 N, 3 OHydrogen nitrateHNO3

Sulphuric acid2 H, 1 S, 4 OHydrogen sulphateH2SO4

Hydrochloric acid1 H, 1 ClHydrogen chlorideHCl

Carbon dioxide

Carbon monoxide

ii. Large regular structures E.g. Iron sulphide

c. Chemical formula Unique to compounds Represent the ratio of atoms of each element that are bonded together If it changes different compound Changes in Chemical formula is represented by a word equation E.g. Iron + Sulphur Iron sulphide Sodium carbonate + Calcium chloride Sodium chloride + Calcium carbonate Reactants Products Can also be represented by particle diagram

d. Physical changes Vs Chemical changesPhysical changeChemical change

No new substances formedNew substances are formed

Easy to reverseCan be different to change

May require heatingMay require heating

Usu. No heat is givenHeat is usu. given out

e. Types of chemical changes Oxidation (1) Formation of oxide E.g. Iron sulphide + oxygen iron oxide + sulphur dioxide Brass yellow red Decomposition Involving one kind of reactant E.g. copper carbonate copper oxide + carbon dioxide green black Precipitation Formation of solids in a solution Usu. w/o heating E.g. sodium carbonate + copper sulphate copper carbonate (solid) + sodium sulphate

f. Mixtures Involves two or more types of pure substances A pure substance contains only one element or compound Components of mixtures can be in various ratios E.g. inhaled air vs exhaled air No chemical bonds formed in between Cannot be represented by a chemical formula Can be separated by physical methods while compounds can only be separated by chemical methods like electrolysis

g. Points of a substance

Definition Melting point From solid to liquid (melt) Freezing point From liquid to solid Boiling point From liquid to gas (evaporate) Pure substances have sharp points ; Mixtures melts or boils over a range of temperatures Impurities will lower ones melting point or boiling point Explained by particle diagramse.g. Solder

Application: spreading salts on the roads in winter water does not freeze easily Application: checking the purity (does not know the identity of the impurities)

f. Alloys Mixture of metals Pure metals may be too soft, too fragile, too easily being corroded Properties of alloys depend on the relative ratio of the metals being mixed E.g. Carat gold system Other examples of alloys: steel (Carbon, iron, and some other metals), solder( tin and lead), brass (copper and zinc).

9A Inheritance and Selection9A Inheritance and SelectionSpeciesHybridGenesCharacteristicsVariationsEnvironmentFertilizationBreedingCloningGenetic modificationGametes

a. Types of organisms Species Similar organisms that can reproduce Hybrid Mix of two different species that results in one which cannot reproduce

b. Characteristics e.g. eye colour, skin colour, hair colour, disease resistance that can describe one entity controlled by DNA which contain the inherited genetic information difference in characteristics among members of a species variation

c. Causes of variation Genetic factor Genes Half from mother; half from father Gender is determined by sex chromosomes

Gametes Sperm cell The tip of head Contains chemicals that dissolve the jelly coat of egg cell and help sperm cell to burrow in. Very little cytoplasm Thin streamlined shape to reduce resistance Tail Allows it to swim Egg cell Large cytoplasm Food reserve for the fertilized egg cell Jelly coat Ensure only one sperm cell can enter Both sperm cell and egg cell have nucleus containing half of the chromosomes Dominant vs Recessive character

Mutation Changes in genes Sources: X ray Gamma ray Allergen Usu. bad e.g. malignant tumor

Environment factor Can benefit and suffer from the change Occur very slowly Caused by damages Wearing Sunlight Heat resistance Diseases HSW: Life process Movement Reproduction Sensitivity Growth Respiration Excretion Nutrition Classify causes into environmental and genetic

d. Artificial modification on characteristics Breeding Selective breeding E.g. Dogs are mated according to speed and character Cross breeding Different breeds are mated E.g. good milk cow + good meat cow good meat and milk cow Problem: may result in defects

Cloning To create exact copies Can solve food supply problem but the species will be too vulnerable to environmental changes Process Nucleus from an adult sheep cell is placed inside an empty egg cell Egg cell grow into an embryo The embryo is placed in the uterus of a sheep Although have exact genes, but the growing environment may be different

Genetically modification A desired gene is put into the DNA of a desired animal E.g. Spidergoat -- spider silk gene is put into the DNA of a goat (cloned afterwards) to produce Biosteel E.g. Insulin bacteria the gene for the production of insulin in pigs are put into the DNA of a bacterium E.g. Genetically modified (GM) sweetcorn Potential danger GM may kill insects that normally eat it GM contains genes that they do not naturally contain Spread of diseases

e. Gardeners tricks Artificial breeding Transfer of pollen grains Stigma of flowers Pollen grains pass from pollen tube to ovary Nucleus of pollen grain finally reaches ovum Fertilized egg will grow into seeds Take-a-cutting Asexual reproduction does not require gametes Part of the parent plant can form a new plant Reason for decreasing the biodiversity little resistance to environmental changes

9B Fit and Healthya. Definition of fitness S-factors: Suppleness stretching Strength weight pulling Speed running Stamina (the time length of doing sth)

The coordination of different organ systems Digestive food glucose Breathing oxygen Circulatory carry oxygen and glucose to muscles Skeletal Bones and Muscles Muscles aerobic and anaerobic respiration energy for work

Ways to improve the performance of the factors Balanced diet (proteins, fat, carbohydrates, water, minerals and vitamins, fiber) Muscle training Better coordination of heart and lung Stronger heart muscles

Slower resting heartbeat rates and fast recovery after exercise Pattern of heartbeat rate an indicator for how fit you are

Notes: Length of exercise, slope of the curve, level of heart rate Plenty of sleep enough spirit Choice of sports Swimming, weight training, football, table tennis, hiking, cricket 9ba7

b. Breathing Terms Breathing Change in volume of your lung Ventilation Air flow during breathing Nose Trachea Bronchi Bronchiole Air sac Gas exchange The absorption of O2 and removal of CO2 at the air sac/ alveoli Respiration Glucose + O2 CO2 + H2O Occurs in the cells

Breathing action Inhalation1. Muscles between ribs (intercostal muscles) contract and pull the ribs up and out2. The diaphragm contracts and moves down. (flattened)3. The volume of the lung increases pressure decreases4. Air moves in. Exhalation1. Muscles between ribs relax and the ribs move back down2. The diaphragm relaxes and moves up. (dome-shaped)3. The volume of the lung decreases pressure increases4. Air moves out. Model Balloon lungs Rubber sheet diaphragm

c. Smoking Ciliated epithelial cells Ciliated epithelial cells along the respiratory tract produce mucus to trap dust and germs Cilia (hairs) on them sweep the mucus to mouth for coughing out or swallowing. If the tract is narrowed by the swollen blood vessels stuffy nose

Bad things about smoking Nicotine make arteries narrower, may stop blood flow If occurs in the heart and brain, stroke or heart attack may result easily CO stop red blood cells carrying oxygen Tar lung damage (ciliated epithelial cells, air sac, irritation) and lung cancer Non-smokers are also subjected to the damage Model demonstrating the effect smoking machine Cotton wool turns yellow (oily) Acidic Limewater turns white

d. Health problems regarding diet Two extremes (Anorexia vs Obesity)

NutrientRecommended daily amount for 14-year-olds*Deficiency diseaseProblems if too much eaten

ProteinMore in boysKwashiorkor swollen tummy, liver damage-

CalciumMore in boysRickets weak bones with odd shapesKidney damage

IronMore in girlsAnaemia tiredness and shortness of breathHeart damage Liver damage

Vitamin A-Liver damage and night-blindness inability to see in dim lightTissue damageLoss of coordination

Vitamin B1-Beriberi paralysis, swelling in the limbs-

Vitamin C-Scurvy bleeding gums-

Remarks: Test the presence of vitamin C by DCPIP

e. Addictive and Depressants Stimulant Increase the speed that neurons carry electrical signals (impulse) Can cause liver damage because of too much workload Depressant Slow the neurons down Too much intake can stop the heart and lung functioning cause brain damage liver damage

AddictiveStimulantDepressantHealth problems

Caffeine if overdosed, mental illness and withdrawal effects will result liver damage

Cannabis memory loss liver damage

Ecstasy mental illness kidney problems liver damage

Cocaine artery blockage liver damage

Heroin vein collapse vomiting severe headache liver damage

Nicotine artery narrowing increase blood pressure and heart rate (why?) liver damage

Alcohol Brain damage if heavy for a long time Deficiency disease of vitamins liver damage

f. Skeletal system

Exploring Science Year 99C Photosynthesisa. Comparison between photosynthesis and respirationPhotosynthesisRespiration

Equation Light energyCO2 + H2O ----------------------------> Chlorophyll Glucose + O2

Light energy to chemical energyGlucose + O2 --------> CO2 + H2O

Useful products Glucose and O2 Energy

Essential factor for the reactions

Light Chlorophyll (capture light) CO2 H2O Glucose O2

Reaction place Chloroplasts in cell Mitochondria in cell

Photosynthesis and respiration assist each other and maintaining a balanceQuestion: rate of photosynthesis and respiration in a day

The higher rate dominates

b. Limiting factor The factor that will affect the rate of photosynthesis Direct: Light Chlorophyll CO2 Indirect H2O Minerals like magnesium, nitrates *Experiments More of direct factors faster photosynthesis

c. Different parts of the plant Transport Xylem dead cells transport water and minerals from root to leaf Phloem transport glucose or converted sugars but not oxygen from leaf to different parts of the plant Case of flooding in roots Root Root hair cell Increase the surface area absorb water quickly Water is important because For photosynthesis For cooling of leaves under strong light For support by turgid pressure For chemical medium If too little water wilting Stomata (not a cell) With guard cells Similar to air sac place for gaseous exchange When too less water stomata will be closed by guard cell Palisade cell Densely closed packed near the leaf surface maximum light Lots of chloroplasts maximum absorption Able to shift in the cell maximum absorption minimum damage How to reduce water loss in plants?

d. Use of products from photosynthesis Biomass All materials in an organisms Use of glucose (6 C, 12 H, 6 O) Aerobic respiration energy + minerals (e.g. nitrates) amino acids proteins growth and repair Cellulose cell wall Starch energy store Fats cell membrane and energy storee. Farming methods increase crop yield for profits Use of machines Reduce processing time Use of toxic chemicals Pesticides kill pests Insecticides kill insects Fungicides kill fungi that stop plants from photosynthesizing Herbicides (selective) eliminate weeds that compete nutrients Ethylene speeds up ripening Genetic combination / selective breeding Increase crop yield and sustainability Fertilisers Supply sufficient minerals to the crops Minerals Potassium salts enzymes in respiration and photosynthesis Magnesium salts chlorophyll Phosphates cell membrane and healthy roots Nitrates proteins growth and chlorophyll Organic or inorganic Greenhouse Make sure the plants have the best conditions for growth Essential: Temperature Light Humidityf. Farming problems Water pollution Algae boom Death of water organisms Kill helpful insects But is biological feasible? Affect local food web Accumulation of toxic chemicals in the food web GM food may distort the food web and may be harmful to some pollinating insects Deforestation Carbon cycle

Oxygen produced by photosynthesis in plants and CO2 is absorbed CO2 is released by respiration and O2 is absorbed The further introduction of CO2 from the Combustion of coal and oil Combustion of fire wood increasing amount of atmospheric CO2 global warming

9L Pressure and MomentsDefinition of Pressure The amount of force acting on a certain area. The bigger the force, and the smaller the area bigger pressure Formula: !!!Beware of the units Suppose you are stepped by a woman who weighs 60 kg and is wearing high heels. If a typical high heels has an area of 0.0004 m2, how much pressure will the high heels act on your feet?

Fluid pressure Include gases / liquids The origin of pressure Random bumping of particles into each other and any surface The force of particles hitting surfaces creates pressure. The higher the frequency of collision per unit area the greater the pressure will be. The pressure of gas and liquid comes from all directions. E.g. car tyres Water pressure Increase with depthQuiz: Why dams are built with a thicker bottom?

Note that water is not compressible how to control the size of force? Hydraulic system Principle: Piston with different areas Assume the area of Y is 20cm2. What the force at Y?(Hint: the pressure within a fluid (gas/liquid) is the same through the fluid)

A smaller force generates a bigger force is conservation of energy being violated? No, energy depends on the force and the distance moved by the piston. Although the force at Y is bigger, the distance it moves is smaller conservation still retains

Atmospheric pressure Decrease with heightQuiz: Why decrease with height?

Living things and pressure?

What will happen if water pressure and atmospheric pressure are used together? Note that water is not compressible but gas is.

Lever system Effort, Pivot and Load Moment The turning effect of a force Unit: Newton metres

Formula: Moment (Nm) = Force(N) x Perpendicular distance of the force from the pivot(m) If moment creates a turning, what can stop the object from turning? Counter-moment IF Clockwise Moment = Anticlockwise Moment Balance / Equilibrium Quiz: If the distance of the left-hand load is now 20 m from the tower, what the maximum load the crane can lift? Quiz: If one of the moveable concrete blocks is removed, what will happen to the crane if the crane is still at the same position?

9K Speeding Up1. Speed Mean speed: Average of two speeds E.g. Tom rides a bicycle. For the first 30 mins, he rides at 5 m/s. Later, he rides at 10 m/s for 45 mins. Calculate the mean speed of Toms journey.Solution:Total distance = Total time = Mean speed = =

= Units: Speed: m/s or km/h Distance: m or km Time: s or h

2. Effect of Forces on Speed **Force exerted on the same body Balanced force = steady constant speed or remain at rest resultant force = 0e.g. ping pong ball, plane

Unbalanced force net resultant force Acceleration Increasing or Decreasing speeds

3. Acceleration Acceleration depends on: Size of the force Mass of the object Force = Mass x Acceleration Unit: Mass: kg Force = N Acceleration = m/s/se.g. A drag racer accelerates at 30 m/s/s. Its mass is 950 kg. What force does its engine produce?

4. Parachuting Demonstrate the effect of balance and unbalanced forcesTwo forces: weight VS Air resistance Learn how to read a distance-time graph

The steeper the slope, the greater the speed.5. Air resistance More streamlined less air resistance Greater weight less effect from air resistance move faster E.g. The case for a balloon and a cannon ball

9Ka6B5

Label the parts

What does the hair do?Name three component in the cigarette smoke is harmful to our health. Please describe the impact.Why smoking increases the heart disease? Why heart rate increases?

Label Coronary arteries function?Large blood vesselsAtriumVentricles

Which side has a thicker wall? Why?Difference between atrium and ventricle

Exploring Science Year 99C Photosynthesis

Process of photosynthesis and related experiments for the limiting factorAdaptation of plants for photosynthesis and respirationChemicals used for increasing crop yieldProblems with the boosting of crop yield