Year 8 Biology Knowledge Organiser Topic 1: Health And .

Year 8 Biology Knowledge OrganiserTopic 1: Health and LifestyleKPI 1: Describe the requirements for a healthy human diet.There are 7 major food groups, a balanced diet will contain the correctamounts of all of these for the person’s needs, e.g. someone who does alot of exercise will need a lot more carbohydrate than someone who doesnot. The seven food groups are summarised below:Food GroupExampleFunctionProteinFish, meat,dairyFor growth and repair.FatButter, oils,nutsTo provide energy. Fat provides a long termstore of energy. It also provides insulation forthe body.CarbohydrateBread, pasta,sugarTo provide energy.FibreVegetables,BranTo help food move through the gut.MineralsDairy(calcium)Required in small amounts to remainhealthy, for example calcium is crucial forhealthy teeth and bones.VitaminsOranges(vitamin C),Carrots(vitamin A)Required in small amounts to remainhealthy, for example vitamin D is needed tokeep teeth and bones healthy.WaterWater, fruitjuice, milkNeeded to form the cytoplasm of the cellsand other fluids.Deficiency DiseasesDeficiency diseases are when the body does not get enough of a certainnutrient. For example a lack of vitamin C can lead to scurvy which affectsthe gums. A lack of vitamin D can lead to rickets which affects the bones.Key TermsDefinitionsKilojoules (kJ)A unit used to measure energy in foodsDeficiencyDiseaseA disease caused by the lack of a nutrientEnergy in FoodThe energy in food is often measured in kJ,the amount of energy you need dependson your lifestyle. If there is an imbalanceyou will put on or loose weight.Food TestsThere are some simple chemical tests that can be carriedout, to see what food groups are present. If iodine is addedto starch it will turn blue/black. If Benedict's solution isadded to a sugar it will go orange. To test for fat, mix thesubstance with a small amount of ethanol and distilledwater, if a milky white emulsion appears, then fat ispresent.Measuring Energy in FoodThe energy in different foods can be measured using asimple experiment. If the food is set on fire, it can be usedto heat up water and by measuring the temperature change,you should be able to see which foods cause the greatestrise in temperature and have given out the most energy.

Year 8 Biology Knowledge OrganiserTopic 1: Health and LifestyleKey TermsDefinitionsEnzymesProtein molecules that speed up chemicalreactionsKPI 2: Describe digestion at the molecular level.DigestiveSystemThe organ system that breaks down food intosmall moleculesMechanicalDigestionWhen large pieces of food are broken downinto smaller ones (e.g. by chewing)ChemicalDigestionWhen food is broken down into small solublechemicals, enzymes help with thisFood is digested in the digestive system, this is an organ system. Youshould be able to name all parts of diagram below: The mouth has teeth that mechanicallydigest the food, it also has a salivary glandthat releases enzymes to break the fooddown. The oesophagus is a muscular tube thatpushes the food into the stomach The stomach churns the food up, whilealso adding acid and enzymes to break thefood down. In the small intestine, food is broken downfurther and is absorbed thorough the walls ofthe intestine into the blood stream. The large intestine absorbs any remaining water Finally the food passes through the anus as faecesEnzymesEnzymes help to break down larger food molecules intosmaller ones, so that they can be absorbed through the wallsof our small intestines, into our blood stream.Proteins, carbohydrates and fats each have their own enzymethat breaks them down.KPI 3: Realise the possible ill-effects of recreational drugsDrugs can be divided up into two types, medicinal which are prescribed to treat an illness and recreational, which are taken for pleasure.Some recreational drugs are legal and others are illegal.Type of drugEffect on the bodyExampleStimulantSpeeds up reactionsCaffeine (legal) Cocaine (illegal)DepressantSlows down reactionsAlcohol (legal) Cannabis (illegal)PainkillerStops the feeling of painMorphine (legal) Heroin (illegal)

Year 8 Physics Knowledge OrganiserTopic 2: Electricity and MagnetismKey TermsDefinitionsPotentialDifferenceThe difference in energy between two points in an electriccircuitKPI 1: Compare current and static electricity and explain currentelectricity in terms of current, voltage and resistance.CurrentThe number of electrons flowing past a point in 1 secondResistanceSomething that resists the flow of an electric chargeSome particles are electrically charged e.g. electrons, these cantherefore carry an electric charge. There are two types ofelectricity1. Static Electricity2. Current ElectricityIn static electricity, when two insulators are rubbed together,electrons are transferred, causing an electric charge to build up.ElectronA charged particle which flows in an electric circuitConductorA material which allows the flow of electric chargeInsulatorA material that slows the flow of electric chargeWhen this happens one object has a positive charge and one willhave a negative charge, like charges repel and opposite chargesattract.Current ElectricityCurrent electricity occurs in conductors, for example metals, wherethe electrons can flow. Electric current is how many electrons areflowing in one second measured in Amps (A). For electric current toflow, we require a complete circuit.The potential difference in an electric circuit is the difference inenergy between two different parts of the circuit. This is measured involts (V). Sometimes people call potential difference voltage and it isstill measured in volts.Resistance in an electric circuit is anything which slows the flow ofelectric charge, resistance is measure in Ohms ( ).Circuit SymbolsWhen drawing an electric circuit, we use different symbols to represent different components, the symbols you need to memorise are:

Year 8 Physics Knowledge OrganiserTopic 2: Electricity and MagnetismKey TermsDefinitionsSeries CircuitA circuit where all the components are in thesame loop.KPI 2: Compare current and voltage in series and parallel circuits.ParallelCircuitA circuit where the components are indifferent loops in the circuit.Circuits can be connected in two ways:1. Series Circuits2. Parallel CircuitsIn a series circuit all of the components are in the same loop, below is anexample of two lamps in a series circuit. If either of the lamps were tobreak the circuit would not be complete and the light bulb would go out.AmmeterAn electrical component that measures thesize of electric current, it is connected inseries in a circuit.VoltmeterAn electrical component that measures thesize of the potential difference, it isconnected in parallel.The current is the same at any point in a series circuit as current is alwaysconserved in a circuit.Parallel CircuitsIn a parallel circuit components are in more than one loop.Lights in a house are connected in parallel, when one lightbulb breaks the whole circuit is not broken so the other lightbulb will stay alight.Measuring Current and VoltageIn a parallel circuit the current splits atjunctions, see the example. The currenton the different branches of the circuitmust add up to the total current.

Year 8 Physics Knowledge OrganiserTopic 2: Electricity and MagnetismOhm’s LawCurrent, voltage and resistance are all linked by Ohm’s Law, it states that:Resistance Voltage Current or R V IKPI 3: Explain the difference between bar magnets and electromagnets.Bar MagnetsBar magnets have two poles, a North pole (N) and a South pole (S),opposite poles attract and like poles repel.Magnets create magnetic fields. These cannot be seen. They fill the spacearound a magnet where the magnetic forces work, where they can attractor repel magnetic materials.Although we cannot see magnetic fields, we can detect them using ironfilings. The tiny pieces of iron line up in a magnetic field. We can drawsimple magnetic field line diagrams to represent this. In the diagram, notethat: field lines have arrows on them field lines come out of N and go into S field lines are more concentrated at the poles.The magnetic field is strongest at the poles, where the field lines aremost concentrated.The Earth has a magnetic field because thecore rotates, it acts like a giant bar magnet.Key TermsDefinitionsOhm’s LawA mathematical law that links current,voltage and resistanceElectromagnetA magnet created by the flow of electricityin a wireMagnetic FieldThe area around a magnet, where themagnetic field actsElectromagnetsWhen an electric current flows through a wire, it creates amagnetic field, this can be used to make an electromagnet,by making the wire into a coil.You can increase the strength of an electromagnet by doingthree things:1. Increase the number of coils2. Increase the current3. Add a soft iron coreThe motor effect: A simple electric motor can be built usinga coil of wire that is free to rotate between two oppositemagnetic poles. When an electric current flows through thecoil, the coil experiences a force and moves. This is called themotor effect.

Year 8 Chemistry Knowledge OrganiserTopic 3: Periodic TableKey TermsDefinitionsAtomContains protons neutrons and electrons, andmakes up all elementsKPI 1: Describe the arrangement of elements in the periodic table.ProtonA sub atomic particle with a positive chargeElectronA sub atomic particle with a negative chargeNeutronA sub atomic particle with a neutral chargeAtomic numberThe number of protons in an atomAll the different elements are arranged on the periodic table. Theelements are arranged in order of increasing atomic number.On the periodic table, we can see the metal elements and non metalelements.The section in the middle of the periodic table is known as thetransition metals.Structure of the Atom An atom is made up of three subatomic particles: protons,electrons and neutrons. Protons and neutrons are found in the nucleus of the atom (in thecentre). Electrons are found orbiting the nucleus in shells (also known asenergy levels). Protons have a positive charge. Electrons have a negative charge. Neutrons have a no charge.Mendeleev Throughout history scientists have tried to classify substancesand many scientists attempted to construct a periodic table. Before the knowledge of the atom, scientists arranged theperiodic table by atomic weight and this meant the groupswere not always correct. In 1869 Dimitri Mendeleev a Russian scientist, published hisperiodic table, it was slightly different to those that had beenbefore. He still arranged elements by atomic weight but healso left gaps for where he predicted elements would be. He very accurately predicted the properties of elements thatwere not discovered until many years later e.g. Gallium.Atomic Number and Mass NumberThis is the total of protons neutronsThis is the number of protonsTherefore sodium has 11 protons, 11 electrons and 23-11 12 neutrons.The Modern Periodic TableThe modern periodic table arranges the atoms by increasingatomic number. There are currently 118 elements with somebeing discovered as recently as 2016!