OCR Level 1/2 GCSE (9–1) in Physics A (Gateway Science) (J249) Foundation Tier Paper 1/Higher Tier Paper 3 and OCR Level 1/2 GCSE (9–1) in Combined Science A (Gateway Science) (J250) FT Paper 5/HT Paper 11 Physics Syllabus-specification CONTENT INDEX (NEW for Y10 starting September 2016, first exams from 2018 onwards) 'Old' OCR Gateway GCSE sciences for Y11 finishing Y11 2016-2017 Everything below is based on the NEW 2016 official syllabus-specifications for Y10 2016 onwards Syllabus-specification CONTENT INDEX for OCR GCSE Gateway Science A (HT only) means higher tier only (NOT FT), (GCSE physics only) means NOT for GCSE Combined Science physics Revision summaries for OCR GCSE Physics A FT Paper 1 and HT Paper 3 AND GCSE Combined Science FT Paper 5/HT Paper 11 (this page) Revision SUMMARY for Topic P1 Matter
Revision SUMMARY for Topic P2: Forces
Revision SUMMARY for Topic P3 Electricity (GCSE Physics only)
Revision SUMMARY for Topic P4: Magnetism and magnetic fields (GCSE Physics only)
Revision SUMMARY for Topic 3 Electricity and Magnetism (GCSE Combined Science only) This Combined Science Topic combines parts of Topic 3 and Topic 4 in the separate science GCSE Physics course.
Revision summaries for OCR GCSE Physics A FT Paper 2 and HT Paper 4 AND GCSE Combined Science FT Paper 6/HT Paper 12 (separate page) Revision SUMMARY for Topic P4 Waves and Radioactivity (GCSE Combined Science only) This Combined Science topic includes sections from Topic P5 and Topic P6 from the GCSE Physics course.
Revision SUMMARY for Topic P5: Waves in matter: (GCSE Physics only)
Revision SUMMARY for Topic P6: Radioactive decay – waves and particles: (GCSE Physics only)
Revision SUMMARY for Topic P7: Energy (GCSE Physics) & Topic 5 Energy (GCSE Combined Science)
Revision SUMMARY for Topic P8: Global challenges (GCSE Physics) & Topic 6 (GCSE Combined Science)
Revision summaries for OCR GCSE Physics A FT Paper 1and HT Paper 3 AND Combined Science FT Paper 5/HT Paper 11 Topic P1: Matter P1.1 The particle model Appreciate that knowledge and understanding of the particle nature of matter is fundamental to Physics and an appreciation of matter in its different forms. You must also be aware of the subatomic particles, their relative charges, masses and positions inside the atom. The structure and nature of atoms is essential to the further understanding of physics and is needed to explain many phenomena, for example those involving charge and transfer of charges, as well as radioactivity. You should be aware of a simple atomic model, and that atoms are examples of particles and know the difference between atoms, molecules and compounds. You should understand how density can be affected by the state materials are in. Beware of confusing the different types of particles (subatomic particles, atoms and molecules) and making errors when converting between different units. Be able to used in the measurement of volume. Know and be able to apply the equation: density (kg/m^{3}) = mass (kg)/volume (m^{3}) P1.1a Be able to describe how and why the atomic model has changed over time including the Thomson, Rutherford (alongside Geiger and Marsden) and Bohr models. Check out the timeline showing the development of atomic theory and discussion of the different roles played in developing the atomic model and how different scientists worked together. P1.1b Be able to describe the atom as a positively charged nucleus surrounded by negatively charged electrons, with the nuclear radius much smaller than that of the atom and with almost all of the mass in the nucleus. P1.1c Know the typical size (order of magnitude) of atoms and small molecules typically 1x10^{-10}m P1.1d Be able to define density. From measurements of length, volume and mass be able to calculate density. See also the investigation of Archimedes’ Principal using eureka cans. P1.1e Be able to explain the differences in density between the different states of matter in terms of the arrangements of the atoms and molecules. P1.1f Be able to apply the relationship between density, mass and volume to changes where mass is conserved. P1.2 Changes of state A clear understanding of the foundations of the physical world forms a solid basis for further study of Physics. Understanding of the relationship between the states of matter helps to explain different types of everyday physical changes that we see around us. You should be familiar with the structure of matter and the similarities and differences between solids, liquids and gases. You should have a simple idea of the particle model and be able to use it to model changes in particle behaviour during changes of state. You should be aware of the effect of temperature in the motion and spacing of particles and an understanding that energy can be stored internally by materials. Common misconceptions - assuming atoms are always synonymous with particles, there is actually nothing between the particles, so its wrong to ‘fill’ the gaps with ‘air’ or ‘vapour’. Its not always easy to visualise the 3 dimensional arrangement of particles in all states of matter. You can find it challenging to understand how kinetic theory applies to heating materials and how to use the term temperature correctly, regularly confusing the terms temperature and heat. Be able to apply the following equations with the correct units:
P1.2a Be able to describe how mass is conserved when substances melt, freeze, evaporate, condense or sublimate. Use of a data logger to record change in state and mass at different temperatures. Demonstration of the distillation to show that mass is conserved during evaporation and condensation. P1.2b Be able to describe that these physical changes differ from chemical changes because the material recovers its original properties if the change is reversed. P1.2c Be able to describe how heating a system will change the energy stored within the system and raise its temperature or produce changes of state. Observation of the crystallisation of salol in water under a microscope. Use of thermometer with a range of -10 110°C, to record the temperature changes of ice as it is heated. P1.2d Be able to define the term specific heat capacity and distinguish between it and the term specific latent heat. Investigation of the specific heat capacity of different metals or water using electrical heaters and a joulemeter. P1.2e Be able to apply the relationship between change in internal energy of a material and its mass, specific heat capacity and temperature change to calculate the energy change involved. P1.2f Be able to apply the relationship between specific latent heat and mass to calculate the energy change involved in a change of state. Measurement of the specific latent heat of vaporisation of water. Measurement of the specific latent heat of stearic acid. P1.2g (Combined Science only here, dealt with in Topic 1.3 for GCSE Physics) Be able to explain how the motion of the molecules in a gas is related both to its temperature and its pressure - application to closed systems only. Demonstration of the difference in pressure in an inflated balloon that has been heated and frozen. Building manometers and using them to show pressure changes in heated/cooled volumes of gas. P1.2h (Combined Science only here, dealt with in Topic 1.3 for GCSE Physics) Be able to explain the relationship between the temperature of a gas and its pressure at constant volume (qualitative only). Demonstration of the exploding can experiment. Building of Alka-Seltzer rockets with film canisters. P1.3 Pressure This section develops the understanding of pressure in gases and liquids. Pressure in gases builds on the particle model, and in liquids the increase in pressure with depth is explained as the weight of a column of liquid acting on a unit area. You should be aware of the change in pressure in the atmosphere and in liquids with height (qualitative relationship only). You should have an understanding of floating and sinking and the effect of upthrust. You should know that pressure is measured by a ratio of force over area which is acting at a normal to the surface. Common misconceptions - floating and sinking, based on the premise that light or small objects float and heavy or large objects sink. You may misunderstand the role of pressure difference and suction e.g. the collapsing can and the forcing of air into the lungs during inhalation. Be able to apply: for gases:
P1.3a Be able to explain how the motion of the molecules in a gas is related both to its temperature and its pressure - application to closed systems only. Demonstration of the difference in pressure in an inflated balloon that has been heated and frozen. Building manometers and using them to show pressure changes in heated/cooled volumes of gas. P1.3b Be able to explain the relationship between the temperature of a gas and its pressure at constant volume (qualitative only). Demonstration of the exploding can experiment. Building of Alka-Seltzer rockets with film canisters. P1.3c Know that gases can be compressed or expanded by pressure changes and that the pressure produces a net force at right angles to any surface. Compressing syringes containing sand, water and air. Demonstration of the collapsing can experiment. Demonstration of the Cartesian diver experiment. P1.3d Be able to explain how increasing the volume in which a gas is contained, at constant temperature can lead to a decrease in pressure behaviour - with reference to particle velocity and collisions. Demonstration of the behaviour of marshmallows in a vacuum. P1.3e (HT only) Be able to explain how doing work on a gas can increase its temperature eg action of a bicycle pump. Demonstration of heat production in a bicycle inner tube as it is pumped up. P1.3f Be able to describe a simple model of the Earth’s atmosphere and of atmospheric pressure - an assumption of uniform density. Knowledge of layers is not expected. P1.3g Be able to explain why atmospheric pressure varies with height above the surface of the planet. P1.3h (HT only) Be able to describe the factors which influence floating and sinking P1.3i (HT only) Be able to explain why pressure in a liquid varies with depth and density and how this leads to an upwards force on a partially submerged object. Discussion of buoyancy of a ping pong ball in water. P1.3j (HT only) Be able to calculate the differences in pressure at different depths in a liquid including knowledge that g is the strength of the gravitational field and has a value of 10N/kg near the Earth’s surface Demonstration of differences in water pressure using a pressure can with holes. Topic P2: Forces P2.1 Motion Having looked at the nature of matter which makes up objects, we move on to consider the effects of forces. The interaction between objects leads to actions which can be seen by the observer, these actions are caused by forces between the objects in question. Some of the interactions involve contact between the objects, others involve no contact. You need to consider the importance of the direction in which forces act to allow understanding of the importance of vector quantities when trying to predict the action. You should have a basic knowledge of the mathematical relationship between speed, distance and time. You should also be able to represent this information in a distance-time graph and have an understanding of relative motion of objects. Common misconceptions - you may find the concept of action at a distance challenging, there is a tendency to believe that a velocity must have a positive value and have difficulty in associating a reverse in direction with a change in sign. It is therefore important to make sure you are knowledgeable about the vector / scalar distinction. You need to be able to differentiate between scalar and vector quantities and the idea of objects with a changing direction not having a constant vector value. For example, objects moving in a circle. This issue also arises when trying to handle momentum and changes in momentum of objects colliding. Know and be able to apply the following formulae:
Be able to apply:
P2.1a Be able to describe how to measure distance and time in a range of scenarios P2.1b Be able to describe how to measure distance and time and be able to use these to calculate speed Calculations of the speeds of walkers and run a measured distance. Investigation of trolleys on ramps at an angle and whether this affects speed. P2.1c Be able to make calculations using ratios and proportional reasoning to convert units and to compute rates including conversion from non-SI to SI units P2.1d Be able to explain the vector- scalar distinction as it applies to displacement and distance, velocity and speed P2.1e Be able to relate changes and differences in motion to appropriate distance-time, and velocity-time graphs, and interpret lines, slopes. P2.1f (HT only) Be able to interpret enclosed area in velocity-time graphs and enclosed areas in such graphs P2.1g Be able to calculate average speed for non-uniform motion. P2.1h Be able to apply formulae relating distance, time and speed, for uniform motion, and for motion with uniform acceleration. Practical - investigation of acceleration P2.2 Newton’s Laws Newton’s laws of motion essentially define the means by which motion changes and the relationship between these changes in motion with force and mass. You should have an understanding of contact and non-contact forces influencing the motion of an object. You should be aware of Newtons and that this is the measure of force. The new work here involves studying Newton's three laws of motion (his contribution to physics is recognised by have the unit of force named after him!). You are expected to be able to use force arrows and have an understanding of balanced and unbalanced forces. Common misconceptions - objects needing a net force for them to continue to move steadily and to understand that stationary objects also have forces acting on them. Be able to differentiate between scalar and vector quantities and the idea of objects with a changing direction not having a constant vector value, for example, objects moving in a circle. This issue also arises with the concept of momentum and changes in momentum of colliding objects. Know and be able to apply the following equations:
P2.2a Know examples of ways in which objects interact electrostatics, gravity, magnetism and by contact (including normal contact force and friction) P2.2b Be able to describe how such examples involve interactions between pairs of objects which produce a force on each object P2.2c Be able to represent such forces as vectors including drawing free body force diagrams to demonstrate understanding of forces acting as vectors Measurement of the velocity of ball bearings in glycerol at different temperatures or with ball bearings of differing sizes. P2.2d Be able to apply Newton’s First Law to explain the motion of an object moving with uniform velocity and also an object where the speed and/or direction change including looking at forces on one body and resultant forces and their effects (qualitative only). Demonstration of the behaviour of colliding gliders on a linear air track. Use of balloon gliders to consider the effect of a force on a body. P2.2e (HT only) Be able to use vector diagrams to illustrate resolution of forces, a net force (resultant force), and equilibrium situations - scale drawings. P2.2f (HT only) Be able to describe examples of the forces acting on an isolated solid object or system - examples of objects that reach terminal velocity for example skydivers and applying similar ideas to vehicles. Practical to design and build a parachute for a mass, and measure its terminal velocity as it is dropped. P2.2g (HT only) Be able to describe, using free body diagrams, examples where two or more forces lead to a resultant force on an object. P2.2h (HT only) Be able to describe, using free body diagrams, examples of the special case where forces balance to produce a resultant force of zero (qualitative only). P2.2i Be able to apply Newton's Second Law in calculations relating forces, masses and accelerations. Practicals - use of light gates, weights and trolleys to investigate the link between force and acceleration. P2.2j (HT only) Be able to explain that inertia is a measure of how difficult it is to change the velocity of an object and that the mass is defined as the ratio of force over acceleration. Practical using light gates, weights and trolleys to investigate the link between force and acceleration. P2.2k (HT only) Be able to define momentum and be able to describe examples of momentum in collisions - an idea of the conservation of momentum in elastic collisions. Practicals - use of light gates, weights and trolleys to measure momentum of colliding trollies. Use of a water rocket to demonstrate that the explosion propels the water down with the same momentum as the rocket shoots up. P2.2l (GCSE Physics only) Be able to apply formulae relating force, mass, velocity and acceleration to explain how the changes involved are inter-related P2.2m/l Be able to use the relationship between work done, force, and distance moved along the line of action of the force and be able to describe the energy transfer involved. Practical - measurement of work done by learners lifting weights or walking up stairs. P2.2n/m Be able to calculate relevant values of stored energy and energy transfers; convert between newton-metres and joules P2.2o/n Be able to explain, with reference to examples, the definition of power as the rate at which energy is transferred. P2.2p/o Know and Be able to apply Newton’s Third Law - application to situations of equilibrium and non equilibrium P2.2q/p (HT only) Be able to explain why an object moving in a circle with a constant speed has a changing velocity (qualitative only). Practical demonstration of spinning a rubber bung on a string. P2.3 Forces in action Know that forces acting on an object can result in a change of shape or motion. Having looked at the nature of matter, we can now introduce the idea of fields and forces causing changes. This develops the idea that force interactions between objects can take place even if they are not in contact. They can also still result in an object changing shape or motion. You should be familiar with forces associated with deforming objects, with stretching and compressing (springs). You should have an understanding of forces acting to deform objects and to restrict motion. You should already be familiar with Hooke’s Law and the idea that when work is done by a force; this results in an energy transfer and leads to energy being stored by an object. You are expected to know that there is a force due to gravity and that gravitational field strength differs on other planets and stars. You should be aware of moments acting as a turning force. Common misconceptions - students commonly have difficulty understanding that the weight of an object is not the same as its mass from the use of the term ‘weighing’. The concept of force multipliers can also be challenging even though the basic concepts are ones covered at KS3. Know and be able to apply:
Be able to apply: energy transferred in stretching (J)= 0.5 x spring constant (N/m) x (extension (m))^{2} (GCSE Physics only) P2.3a Be able to explain that to stretch, bend or compress an object, more than one force has to be applied - apply to real life situations Use of a liquorice bungee or spring to explore extension and stretching. P2.3b Be able to describe the difference between elastic and plastic deformation (distortions) caused by stretching forces. Practical - comparisons of behaviour of springs and elastic bands when loading and unloading with weights. P2.3c Be able to describe the relationship between force and extension for a spring and other simple systems - graphical representation of the extension of a spring. Investigation of forces on springs – Hooke’s law P2.3d Be able to describe the difference between linear and non-linear relationships between force and extension. Investigation of the elastic limit of springs and other materials. P2.3e Be able to calculate a spring constant in linear cases P2.3f Be able to calculate the work done in stretching Use of data from stretching an elastic band with weights to plot a graph to calculate the work done. P2.3g Be able to describe that all matter has a gravitational field that causes attraction, and the field strength is much greater for massive objects P2.3h Be able to define weight and describe how it is measured and describe the relationship between the weight of an object and the gravitational field strength (g). Know that the gravitational field strength is known as g and has a value of 10N/kg. Know that weight (N) = mass (kg) x g (N/kg). Be able to calculate weight on different planets. P2.3i Know the acceleration in free fall P2.3j-o are NOT required for the GCSE Combined Science P2.3j (GCSE Physics only) Be able to apply formulae relating force, mass and relevant physical constants, including gravitational field strength (g), to explore how changes in these are inter-related P2.3k (GCSE Physics only) Be able to describe examples in which forces cause rotation- location of pivot points and whether a resultant turning force will be in a clockwise or anticlockwise direction. P2.3l (GCSE Physics only) Be able to define and calculate the moment of the force in such examples. Application of the principle of moments which are balanced. Investigation of moments using a meter ruler, pivot and balancing masses. P2.3m (GCSE Physics only) Be able to explain how levers and gears transmit the rotational effects of forces - an understanding of ratios and how this enables gears and levers to work as force multipliers P2.3n (GCSE Physics only) Know that the pressure in fluids (gases and liquids) causes a net force at right angles to any surface. Demonstration of balloons being pushed onto a single drawing pin versus many drawing pins. P2.3o (GCSE Physics only) Be able to use the relationship between the force, the pressure and the area in contact - an understanding of how simple hydraulic systems work Topic P3: Electricity (GCSE Physics only, parts of it are covered in a separate Topic 3 for Combined Science further down) P3.1 Static and charge This topic considers the interactions between matter and electrostatic fields. These interactions are derived from the structure of matter which was considered in the previous section. The generation of charge is considered. Charge is a fundamental property of matter. There are two types of charge which are given the names 'positive' and 'negative'. The effects of these charges are not normally seen as objects often contain equal amounts of positive and negative charge so their effects cancel each other out. You should be aware of electron transfer leading to objects becoming statically charged and the forces between them and also be aware of the existence of an electric field. Common misconceptions - classifying which materials act as insulators or act as conductors - the role of insulators should not be neglected. Also, remember that positive charge does not move to make a material positive, rather it is the movement of negative electrons.
P3.1a Be able to describe that charge is a property of all matter and that there are positive and negative charges. The effects of the charges are not normally seen on bodies containing equal amounts of positive and negative charge, as their effects cancel each other out. Practicals: Use of charged rods to repel or attract one another. Use of a charged rod to deflect water or pick up paper. Discussion of why charged balloons are attracted to walls. P3.1b Be able to describe the production of static electricity, and sparking, by rubbing surfaces, and evidence that charged objects exert forces of attraction or repulsion on one another when not in contact. Know and understand that static charge only builds up on insulators. Demonstration of, and uses of a Van de Graaff generator. P3.1c Be able to explain how transfer of electrons between objects can explain the phenomena of static electricity. Use of the gold leaf electroscope and a charged rod to observe and discuss behaviour. P3.1d Be able to explain the concept of an electric field and how it helps to explain the phenomena of static electricity how electric fields relate to the forces of attraction and repulsion. Demonstration of semolina on castor oil to show electric fields. P3.1e Know that current is a rate of flow of charge (electrons) and the conditions needed for charge to flow conditions for charge to flow including the source of potential difference and a closed circuit. P3.1f Know that current has the same value at any point in a single closed loop P3.1g Know and be able to use the relationship between quantity of charge, current and time P3.2 Simple circuits Know that electrical currents depend on the movement of charge and the interaction of electrostatic fields. The electrical current, potential difference and resistance are all covered in this topic. The relationship between them is considered and you will represent this, using circuits. You should have been introduced to the measurement of conventional current and potential difference in circuits. You will have an understanding of how to assemble series and parallel circuits and a basic understanding of how they differ with respect to conventional current and potential difference. You are expected to have an awareness of the relationship between potential difference, current and resistance and the units in which they are measured. Common misconceptions - the concept of potential difference may be very difficult to grasp. You may find it difficult to understand the behaviour of charge in circuits and through components and how this relates to energy or work done within a circuit Know and be able to apply the following equations:
P3.2a Be able to describe the differences between series and parallel circuits - position of measuring instruments in circuits and descriptions of the behaviour of energy, current and potential difference Practical - building of circuits to measure potential difference and current in both series and parallel circuits. P3.2b Be able to represent d.c. circuits with the conventions of positive and negative terminals, and the symbols that represent common circuit elements - diodes, LDRs and thermistors, filament lamps, ammeter, voltmeter, resistors Practical building circuits from diagrams. P3.2c Know that current (I) depends on both resistance (R) and potential difference (V) and the units in which these are measured including the definition of potential difference Practical - recording of p. d. across and current through different components and calculate resistances. P3.2d Know and be able to apply the relationship between I, R and V, and that for some resistors the value of R remains constant but that in others it can change as the current changes. Investigation of resistance in a wire. Investigation of the effect of length on resistance in a wire. P3.2e Be able to explain that for some resistors the value of R remains constant but that in others it can change as the current changes P3.2f Be able to explain the design and use of circuits to explore such effects including components such as wire of varying resistance, filament lamps, diodes, thermistors and LDRs P3.2g Be able to use graphs to explore whether circuit elements are linear or non-linear. Investigation of I-V characteristics of circuit elements. P3.2h Be able to use graphs and relate the curves produced to the function and properties of circuit elements including components such as wire of varying resistance, filament lamps, diodes, thermistors and LDRs Use of wires, filament lamps, diodes, in simple circuits. Alter p.d. and keep current same using variable resistor. Record and plot results. P3.2i Be able to explain why, if two resistors are in series the net resistance is increased, whereas with two in parallel the net resistance is decreased (qualitative explanation only). Investigation of the brightness of bulbs in series and parallel. P3.2j Be able to calculate the currents, potential differences and resistances in d.c. series and parallel circuits including components such as wire of varying resistance, filament lamps, diodes, thermistors and LDRs. Investigation of resistance of a thermistor in a beaker of water being heated. Investigation of resistance of an LDR with exposure to different light intensities. Investigation of how the power of a photocell depends on its surface area and its distance from the light source. P3.2k Be able to explain the design and use of such circuits for measurement and testing purposes P3.2l Be able to explain how the power transfer in any circuit device is related to the potential difference across it and the current, and to the energy changes over a given time. P3.2m Be able to apply the equations relating potential difference, current, quantity of charge, resistance, power, energy, and time, and solve problems for circuits which include resistors in series, using the concept of equivalent resistance. Topic P4: Magnetism and magnetic fields P4.1 Magnets and magnetic fields Having an understanding of how charge can be generated and its effects, we can now consider the effects of movement of charge in magnetism. You will look at magnets and magnetic fields around magnets and current-carrying wires. You should have been introduced to magnets and the idea of attractive and repulsive forces and have an idea of the shape of the fields around bar magnets. You are expected to have an awareness of the magnetic effect of a current and electromagnets. Common misconceptions - larger magnets will always be stronger magnets. You may have difficulty understanding the concept of field line density being an indicator of field strength. You should know that the geographic and magnetic poles are not located in the same place. P4.1a Be able to describe the attraction and repulsion between unlike and like poles for permanent magnets including diagrams of magnetic field patterns around bar magnets to show attraction and repulsion. Use of suspended magnets to show attraction and repulsion. P4.1b Be able to describe the difference between permanent and induced magnets. P4.1c Be able to describe the characteristics of the magnetic field of a magnet, showing how strength and direction change from one point to another including diagrams of magnetic field patterns around bar magnets to show attraction and repulsion and also depict how the strength of the field varies around them. Practical - plotting of magnetic fields around different shaped magnets. P4.1d Be able to explain how the behaviour of a magnetic (dipping) compass is related to evidence that the core of the Earth must be magnetic. P4.1e Be able to describe how to show that a current can create a magnetic effect and describe the directions of the magnetic field around a conducting wire. Investigation of the magnetic field around a current-carrying wire using plotting compasses. P4.1f Know that the strength of the field depends on the current and the distance from the conductor. P4.1g Be able to explain how solenoid arrangements can enhance the magnetic effect. Investigation of the magnetic field around a current-carrying solenoid using plotting compasses. Investigation of the factors that can affect the magnetic effect e.g. number of turns, current, length and cross sectional area. P4.2 Uses of magnetism (GCSE Physics HT only, parts covered in Combined Science Topic 3 near the end of the page) Know that forces show the existence of fields and how they interact with one another but here the force itself is discussed in more depth and then quantified. These forces also lead to the use of magnetic fields to induce electrical currents and the applications of this electromagnetic induction in motors, dynamos and transformers. You will study the manner in which electric and magnetic fields interact to produce a force challenging. You may have difficulty with the right angles and three-dimensional requirements of Fleming’s left-hand rule - your ability to visualise this will impact how you deal with this concept. You may find the action of a commutator difficult to apply in the D.C. motor. The application of changing direction of field in the transformer is found challenging by many learners and hence often leads to a superficial grasp of the working of the transformer. Be able to apply the following equations: (HT only)
P4.2a (HT only) Be able to describe how a magnet and a current-carrying conductor exert a force on one another. Demonstration of the jumping wire experiment. P4.2b (HT only) Be able to show that Fleming’s left-hand rule represents the relative orientations of the force, the conductor and the magnetic field P4.2c (HT only) Be able to apply the equation that links the force on a conductor to the magnetic flux density, the current and the length of conductor to calculate the forces involved P4.2d (HT only) Be able to explain how the force exerted from a magnet and a current-carrying conductor is used to cause rotation in electric motors including an understanding of how electric motors work but knowledge of the structure of a motor is not expected. Practical - construction of simple motors. P4.2e (HT only) Know that a change in the magnetic field around a conductor can give rise to an induced potential difference across its ends, which could drive a current, generating a magnetic field that would oppose the original change. Examination of wind up radios or torches to investigate how dynamos work. Demonstration of induction using a strong magnet and a wire using a zero point galvanometer. P4.2f (HT only) Be able to explain how this effect is used in an alternator to generate a.c., and in a dynamo to generate d.c. Research the structure of dynamos and compare with DC motors. P4.2g (HT only) Be able to explain how the effect of an alternating current in one circuit, in inducing a current in transformers. P4.2h (HT only) Be able to explain how the ratio of the potential differences across the two depends on the ratio of the numbers of turns in each. Practical - building of a step-up and step-down transformer to investigate their effects. P4.2i (HT only) Be able to apply the equations linking the potential differences and numbers of turns in the two coils of a transformer. P4.2j (HT only) Be able to explain the action of the microphone in converting the pressure variations in sound waves into variations in current in electrical circuits, and the reverse effect as used in loudspeakers and headphones including an understanding of how dynamic microphones work using electromagnetic induction Examination of the construction of a loudspeaker. Building of a loud speaker. Topic 3 Electricity and Magnetism (GCSE Combined Science only) This Combined Science Topic combines parts of Topic 3 and Topic 4 in the separate science GCSE Physics course. This topic considers the interactions between matter and electrostatic fields. These interactions are derived from the structure of matter which was considered in the previous section. The generation of charge is considered. Charge is a fundamental property of matter. There are two types of charge which are given the names 'positive' and 'negative'. The effects of these charges are not normally seen as objects often contain equal amounts of positive and negative charge so their effects cancel each other out. P3.1 Static and charge P3.1a Be able to describe that charge is a property of all matter and that there are positive and negative charges. The effects of the charges are not normally seen on bodies containing equal amounts of positive and negative charge, as their effects cancel each other out. Practicals: Use of charged rods to repel or attract one another. Use of a charged rod to deflect water or pick up paper. Discussion of why charged balloons are attracted to walls. P3.1b Be able to describe the production of static electricity, and sparking, by rubbing surfaces, and evidence that charged objects exert forces of attraction or repulsion on one another when not in contact. Know and understand that static charge only builds up on insulators. Demonstration of, and uses of a Van de Graaff generator. P3.1c Be able to explain how transfer of electrons between objects can explain the phenomena of static electricity. Use of the gold leaf electroscope and a charged rod to observe and discuss behaviour. P3.1d Know that current is a rate of flow of charge (electrons) and the conditions needed for charge to flow conditions for charge to flow including the source of potential difference and a closed circuit. P3.1e Know that current has the same value at any point in a single closed loop P3.1f Know and be able to use the relationship between quantity of charge, current and time
P3.2 Simple circuits Know and be able to apply the following equations:
P3.2a Be able to describe the differences between series and parallel circuits - position of measuring instruments in circuits and descriptions of the behaviour of energy, current and potential difference Practical - building of circuits to measure potential difference and current in both series and parallel circuits. P3.2b Be able to represent d.c. circuits with the conventions of positive and negative terminals, and the symbols that represent common circuit elements - diodes, LDRs and thermistors, filament lamps, ammeter, voltmeter, resistors Practical building circuits from diagrams. P3.2c Know that current (I) depends on both resistance (R) and potential difference (V) and the units in which these are measured including the definition of potential difference Practical - recording of p. d. across and current through different components and calculate resistances. P3.2d Know and be able to apply the relationship between I, R and V, and that for some resistors the value of R remains constant but that in others it can change as the current changes. Investigation of resistance in a wire. Investigation of the effect of length on resistance in a wire. P3.2e Be able to explain that for some resistors the value of R remains constant but that in others it can change as the current changes P3.2f Be able to explain the design and use of circuits to explore such effects including components such as wire of varying resistance, filament lamps, diodes, thermistors and LDRs P3.2g Be able to use graphs to explore whether circuit elements are linear or non-linear. Investigation of I-V characteristics of circuit elements. P3.2h Be able to use graphs and relate the curves produced to the function and properties of circuit elements including components such as wire of varying resistance, filament lamps, diodes, thermistors and LDRs Use of wires, filament lamps, diodes, in simple circuits. Alter p.d. and keep current same using variable resistor. Record and plot results. P3.2i Be able to explain why, if two resistors are in series the net resistance is increased, whereas with two in parallel the net resistance is decreased (qualitative explanation only). Investigation of the brightness of bulbs in series and parallel. P3.2j Be able to calculate the currents, potential differences and resistances in d.c. series and parallel circuits including components such as wire of varying resistance, filament lamps, diodes, thermistors and LDRs. Investigation of resistance of a thermistor in a beaker of water being heated. Investigation of resistance of an LDR with exposure to different light intensities. Investigation of how the power of a photocell depends on its surface area and its distance from the light source. P3.2k Be able to explain the design and use of such circuits for measurement and testing purposes P3.2l Be able to explain how the power transfer in any circuit device is related to the potential difference across it and the current, and to the energy changes over a given time. P3.2m Be able to apply the equations relating potential difference, current, quantity of charge, resistance, power, energy, and time, and solve problems for circuits which include resistors in series, using the concept of equivalent resistance. P3.3 Magnets and magnetic fields Having an understanding of the flow of charge and its effects, we can now consider the links between movement of charge and magnetism. You will investigate magnets and magnetic fields around magnets and current-carrying wires. You should have been introduced to magnets and the idea of attractive and repulsive forces. You should have an idea of the shape of the fields around bar magnets. You are expected to have an awareness of the magnetic effect of a current and electromagnets. Common misconceptions - larger magnets will always be stronger magnets. You may have difficulty understanding the concept of field line density being an indicator of field strength. You should know that the geographic and magnetic poles are not located in the same place. Be able to apply the following equations: (HT only)
P3.3a Be able to describe the attraction and repulsion between unlike and like poles for permanent magnets including diagrams of magnetic field patterns around bar magnets to show attraction and repulsion. Use of suspended magnets to show attraction and repulsion. P3.3b Be able to describe the difference between permanent and induced magnets. P3.3c Be able to describe the characteristics of the magnetic field of a magnet, showing how strength and direction change from one point to another including diagrams of magnetic field patterns around bar magnets to show attraction and repulsion and also depict how the strength of the field varies around them. Practical - plotting of magnetic fields around different shaped magnets. P3.3d Be able to explain how the behaviour of a magnetic (dipping) compass is related to evidence that the core of the Earth must be magnetic. P3.3e Be able to describe how to show that a current can create a magnetic effect and describe the directions of the magnetic field around a conducting wire. Investigation of the magnetic field around a current-carrying wire using plotting compasses. P3.3f Know that the strength of the field depends on the current and the distance from the conductor. P3.3g Be able to explain how solenoid arrangements can enhance the magnetic effect. Investigation of the magnetic field around a current-carrying solenoid using plotting compasses. Investigation of the factors that can affect the magnetic effect e.g. number of turns, current, length and cross sectional area. P3.3h (HT only) Be able to describe how a magnet and a current-carrying conductor exert a force on one another. Demonstration of the jumping wire experiment. P3.3b (HT only) Be able to show that Fleming’s left-hand rule represents the relative orientations of the force, the conductor and the magnetic field P3.3c (HT only) Be able to apply the equation that links the force on a conductor to the magnetic flux density, the current and the length of conductor to calculate the forces involved P3.3k (HT only) Be able to explain how the force exerted from a magnet and a current-carrying conductor is used to cause rotation in electric motors including an understanding of how electric motors work but knowledge of the structure of a motor is not expected. Practical - construction of simple motors. Doc Brown's Science Website PLEASE NOTE (temporarily) old GCSE courses (finishing 2017): OCR GCSE 21st Century SCIENCES A * OCR GCSE Gateway SCIENCES B For latest developments visit https://twitter.com/docbrownchem |