CIE 0625

Know that forces may produce changes in the size and shape of an object

Sketch, plot and interpret load–extension graphs for an elastic solid and describe the associated experimental procedures

Determine the resultant of two or more forces acting along the same straight line

Know that an object either remains at rest or continues in a straight line at constant speed unless acted on by a resultant force

State that a resultant force may change the velocity of an object by changing its direction of motion or its speed

Describe solid friction as the force between two surfaces that may impede motion and produce heating

Know that friction (drag) acts on an object moving through a liquid

Know that friction (drag) acts on an object moving through a gas (e.g. air resistance)

Define the spring constant as force per unit extension; recall and use the equation F k = x

Define and use the term ‘limit of proportionality’ for a load–extension graph and identify this point on the graph (an understanding of the elastic limit is not required)

Recall and use the equation F = ma and know that the force and the acceleration are in the same direction

Describe, qualitatively, motion in a circular path due to a force perpendicular to the motion as: (a) speed increases if force increases, with mass and radius constant (b) radius decreases if force increases, with mass and speed constant (c) an increased mass requires an increased force to keep speed and radius constant mv 2 (F = is not required) r

Describe the moment of a force as a measure of its turning effect and give everyday examples

Define the moment of a force as moment = force × perpendicular distance from the pivot; recall and use this equation

Apply the principle of moments to situations with one force each side of the pivot, including balancing of a beam

State that, when there is no resultant force and no resultant moment, an object is in equilibrium

Apply the principle of moments to other situations, including those with more than one force each side of the pivot

Describe an experiment to demonstrate that there is no resultant moment on an object in equilibrium

State what is meant by centre of gravity

Describe an experiment to determine the position of the centre of gravity of an irregularly shaped plane lamina

Describe, qualitatively, the effect of the position of the centre of gravity on the stability of simple objects

State that energy may be stored as kinetic, gravitational potential, chemical, elastic (strain), nuclear, electrostatic and internal (thermal)

Describe how energy is transferred between stores during events and processes, including examples of transfer by forces (mechanical work done), electrical currents (electrical work done), heating, and by electromagnetic, sound and other waves

Know the principle of the conservation of energy and apply this principle to simple examples including the interpretation of simple flow diagrams

Recall and use the equation for kinetic energy 1 2 Ek = mv 2

Recall and use the equation for the change in gravitational potential energy ∆Ep = mg∆h

Know the principle of the conservation of energy and apply this principle to complex examples involving multiple stages, including the interpretation of Sankey diagrams

Understand that mechanical or electrical work done is equal to the energy transferred

Recall and use the equation for mechanical working W = Fd = ∆E

Describe how useful energy may be obtained, or electrical power generated, from: (a) chemical energy stored in fossil fuels (b) chemical energy stored in biofuels (c) water, including the energy stored in waves, in tides and in water behind hydroelectric dams (d) geothermal resources (e) nuclear fuel (f) light from the Sun to generate electrical power (solar cells) (g) infrared and other electromagnetic waves from the Sun to heat water (solar panels) and be the source of wind energy including references to a boiler, turbine and generator where they are used

Describe advantages and disadvantages of each method in terms of renewability, availability, reliability, scale and environmental impact

Understand, qualitatively, the concept of efficiency of energy transfer

Know that radiation from the Sun is the main source of energy for all our energy resources except geothermal, nuclear and tidal

Know that energy is released by nuclear fusion in the Sun

Know that research is being carried out to investigate how energy released by nuclear fusion can be used to produce electrical energy on a large scale

Define efficiency as: (a) (useful energy output) (%) efficiency = (× 100%) (total energy input) (b) (useful power output) (%) efficiency = (× 100%) (total power input) recall and use these equations

Define power as work done per unit time and also as energy transferred per unit time; recall and use the equations W (a) P = t ∆E (b) P = t

Know the distinguishing properties of solids, liquids and gases

Know the terms for the changes in state between solids, liquids and gases (gas to solid and solid to gas transfers are not required)

Describe the particle structure of solids, liquids and gases in terms of the arrangement, separation and motion of the particles and represent these states using simple particle diagrams

Describe the relationship between the motion of particles and temperature, including the idea that there is a lowest possible temperature (−273 °C), known as absolute zero, where the particles have least kinetic energy

Describe the pressure and the changes in pressure of a gas in terms of the motion of its particles and their collisions with a surface

Know that the random motion of microscopic particles in a suspension is evidence for the kinetic particle model of matter

Describe and explain this motion (sometimes known as Brownian motion) in terms of random collisions between the microscopic particles in a suspension and the particles of the gas or liquid

Know that the forces and distances between particles (atoms, molecules, ions and electrons) and the motion of the particles affects the properties of solids, liquids and gases

Describe the pressure and the changes in pressure of a gas in terms of the forces exerted by particles colliding with surfaces, creating a force per unit area

Know that microscopic particles may be moved by collisions with light fast-moving molecules and correctly use the terms atoms or molecules as distinct from microscopic particles

Describe qualitatively, in terms of particles, the effect on the pressure of a fixed mass of gas of: (a) a change of temperature at constant volume (b) a change of volume at constant temperature

Convert temperatures between kelvin and degrees Celsius; recall and use the equation T (in K) = θ (in °C) + 273

Recall and use the equation pV = constant for a fixed mass of gas at constant temperature, including a graphical representation of this relationship

Describe, qualitatively, the thermal expansion of solids, liquids and gases at constant pressure

Describe some of the everyday applications and consequences of thermal expansion

Explain, in terms of the motion and arrangement of particles, the relative order of magnitudes of the expansion of solids, liquids and gases as their temperatures rise

Know that a rise in the temperature of an object increases its internal energy

Describe an increase in temperature of an object in terms of an increase in the average kinetic energies of all of the particles in the object

Define specific heat capacity as the energy required per unit mass per unit temperature increase; recall and use the equation ∆E c = m∆θ

Describe experiments to measure the specific heat capacity of a solid and a liquid

Describe melting and boiling in terms of energy input without a change in temperature

Know the melting and boiling temperatures for water at standard atmospheric pressure

Describe condensation and solidification in terms of particles

Describe evaporation in terms of the escape of more-energetic particles from the surface of a liquid

Know that evaporation causes cooling of a liquid

Describe the differences between boiling and evaporation

Describe how temperature, surface area and air movement over a surface affect evaporation

Explain the cooling of an object in contact with an evaporating liquid

Describe experiments to demonstrate the properties of good thermal conductors and bad thermal conductors (thermal insulators)

Describe thermal conduction in all solids in terms of atomic or molecular lattice vibrations and also in terms of the movement of free (delocalised) electrons in metallic conductors

Describe, in terms of particles, why thermal conduction is bad in gases and most liquids

Know that there are many solids that conduct thermal energy better than thermal insulators but do so less well than good thermal conductors

Know that convection is an important method of thermal energy transfer in liquids and gases

Explain convection in liquids and gases in terms of density changes and describe experiments to illustrate convection

Know that thermal radiation is infrared radiation and that all objects emit this radiation

Know that thermal energy transfer by thermal radiation does not require a medium

Describe the effect of surface colour (black or white) and texture (dull or shiny) on the emission, absorption and reflection of infrared radiation

Know that for an object to be at a constant temperature it needs to transfer energy away from the object at the same rate that it receives energy

Know what happens to an object if the rate at which it receives energy is less or more than the rate at which it transfers energy away from the object

Know how the temperature of the Earth is affected by factors controlling the balance between incoming radiation and radiation emitted from the Earth’s surface

Describe experiments to distinguish between good and bad emitters of infrared radiation

Describe experiments to distinguish between good and bad absorbers of infrared radiation

Describe how the rate of emission of radiation depends on the surface temperature and surface area of an object

Explain some of the basic everyday applications and consequences of conduction, convection and radiation, including: (a) heating objects such as kitchen pans (b) heating a room by convection

Explain some of the complex applications and consequences of conduction, convection and radiation where more than one type of thermal energy transfer is significant, including: (a) a fire burning wood or coal (b) a radiator in a car

Define and use the terms normal, angle of incidence and angle of reflection

Describe the formation of an optical image by a plane mirror and give its characteristics, i.e. same size, same distance from mirror, virtual

State that for reflection, the angle of incidence is equal to the angle of reflection; recall and use this relationship

Use simple constructions, measurements and calculations for reflection by plane mirrors

Define and use the terms normal, angle of incidence and angle of refraction

Describe an experiment to show refraction of light by transparent blocks of different shapes

Describe the passage of light through a transparent material (limited to the boundaries between two mediums only)

State the meaning of critical angle

Describe internal reflection and total internal reflection using both experimental and everyday examples

Define refractive index, n, as the ratio of the speeds of a wave in two different regions

Recall and use the equation sin i n = sin r

Recall and use the equation 1 n = sin c

Describe the use of optical fibres, particularly in telecommunications

Describe the action of thin converging and thin diverging lenses on a parallel beam of light

Define and use the terms focal length, principal axis and principal focus (focal point)

Draw and use ray diagrams for the formation of a real image by a converging lens

Describe the characteristics of an image using the terms enlarged/same size/diminished, upright/inverted and real/virtual

Know that a virtual image is formed when diverging rays are extrapolated backwards and does not form a visible projection on a screen

Draw and use ray diagrams for the formation of a virtual image by a converging lens

Describe the use of a single lens as a magnifying glass

Describe the use of converging and diverging lenses to correct long-sightedness and short- sightedness

Describe the dispersion of light as illustrated by the refraction of white light by a glass prism

Know the traditional seven colours of the visible spectrum in order of frequency and in order of wavelength

Recall that visible light of a single frequency is described as monochromatic

State that there are positive and negative charges

State that positive charges repel other positive charges, negative charges repel other negative charges, but positive charges attract negative charges

Describe simple experiments to show the production of electrostatic charges by friction and to show the detection of electrostatic charges

Explain that charging of solids by friction involves only a transfer of negative charge (electrons)

Describe an experiment to distinguish between electrical conductors and insulators

Recall and use a simple electron model to explain the difference between electrical conductors and insulators and give typical examples

State that charge is measured in coulombs

Describe an electric field as a region in which an electric charge experiences a force

State that the direction of an electric field at a point is the direction of the force on a positive charge at that point

Describe simple electric field patterns, including the direction of the field: (a) around a point charge (b) around a charged conducting sphere (c) between two oppositely charged parallel conducting plates (end effects will not be examined)

Know that electric current is related to the flow of charge

Describe the use of ammeters (analogue and digital) with different ranges

Describe electrical conduction in metals in terms of the movement of free electrons

Know the difference between direct current (d.c.) and alternating current (a.c.)

Define electric current as the charge passing a point per unit time; recall and use the equation Q I = t

State that conventional current is from positive to negative and that the flow of free electrons is from negative to positive

Define electromotive force (e.m.f.) as the electrical work done by a source in moving a unit charge around a complete circuit

Know that e.m.f. is measured in volts (V)

Define potential difference (p.d.) as the work done by a unit charge passing through a component

Know that the p.d. between two points is measured in volts (V)

Describe the use of voltmeters (analogue and digital) with different ranges

Recall and use the equation for e.m.f. W E = Q

Recall and use the equation for p.d. W V = Q

Recall and use the equation for resistance V R = I

Describe an experiment to determine resistance using a voltmeter and an ammeter and do the appropriate calculations

State, qualitatively, the relationship of the resistance of a metallic wire to its length and to its cross-sectional area

Sketch and explain the current–voltage graphs for a resistor of constant resistance, a filament lamp and a diode

Recall and use the following relationship for a metallic electrical conductor: (a) resistance is directly proportional to length (b) resistance is inversely proportional to cross-sectional area

Understand that electric circuits transfer energy from a source of electrical energy, such as an electrical cell or mains supply, to the circuit components and then into the surroundings

Recall and use the equation for electrical power P = IV

Recall and use the equation for electrical energy E = IVt

Define the kilowatt-hour (kW h) and calculate the cost of using electrical appliances where the energy unit is the kW h

Draw and interpret circuit diagrams containing cells, batteries, power supplies, generators, potential dividers, switches, resistors (fixed and variable), heaters, thermistors (NTC only), light- dependent resistors (LDRs), lamps, motors, bells, ammeters, voltmeters, magnetising coils, transformers, fuses and relays and know how these components behave in the circuit

Draw and interpret circuit diagrams containing diodes and light-emitting diodes (LEDs) and know how these components behave in the circuit

Know that the current at every point in a series circuit is the same

Know how to construct and use series and parallel circuits

Calculate the combined e.m.f. of several sources in series

Calculate the combined resistance of two or more resistors in series

State that, for a parallel circuit, the current from the source is larger than the current in each branch

State that the combined resistance of two resistors in parallel is less than that of either resistor by itself

State the advantages of connecting lamps in parallel in a lighting circuit

Recall and use in calculations, the fact that: (a) the sum of the currents entering a junction in a parallel circuit is equal to the sum of the currents that leave the junction (b) the total p.d. across the components in a series circuit is equal to the sum of the individual p.d.s across each component (c) the p.d. across an arrangement of parallel resistances is the same as the p.d. across one branch in the arrangement of the parallel resistances

Explain that the sum of the currents into a junction is the same as the sum of the currents out of the junction

Calculate the combined resistance of two resistors in parallel

Know that the p.d. across an electrical conductor increases as its resistance increases for a constant current

Describe the action of a variable potential divider

Recall and use the equation for two resistors used as a potential divider R1 V = 1 R2 V2

Know that a conductor moving across a magnetic field or a changing magnetic field linking with a conductor can induce an e.m.f. in the conductor

Describe an experiment to demonstrate electromagnetic induction

State the factors affecting the magnitude of an induced e.m.f.

Know that the direction of an induced e.m.f. opposes the change causing it

State and use the relative directions of force, field and induced current

Describe a simple form of a.c. generator (rotating coil or rotating magnet) and the use of slip rings and brushes where needed

Sketch and interpret graphs of e.m.f. against time for simple a.c. generators and relate the position of the generator coil to the peaks, troughs and zeros of the e.m.f.

Describe the pattern and direction of the magnetic field due to currents in straight wires and in solenoids

Describe an experiment to identify the pattern of the magnetic field (including direction) due to currents in straight wires and in solenoids

Describe how the magnetic effect of a current is used in relays and loudspeakers and give examples of their application

State the qualitative variation of the strength of the magnetic field around straight wires and solenoids

Describe the effect on the magnetic field around straight wires and solenoids of changing the magnitude and direction of the current

Describe an experiment to show that a force acts on a current-carrying conductor in a magnetic field, including the effect of reversing: (a) the current (b) the direction of the field

Recall and use the relative directions of force, magnetic field and current

Determine the direction of the force on beams of charged particles in a magnetic field

Know that a current-carrying coil in a magnetic field may experience a turning effect and that the turning effect is increased by increasing: (a) the number of turns on the coil (b) the current (c) the strength of the magnetic field

Describe the operation of an electric motor, including the action of a split-ring commutator and brushes

Describe the construction of a simple transformer with a soft-iron core, as used for voltage transformations

Use the terms primary, secondary, step-up and step-down

Recall and use the equation Vp Np Vs = Ns where p and s refer to primary and secondary

Describe the use of transformers in high- voltage transmission of electricity

State the advantages of high-voltage transmission

Explain the principle of operation of a simple iron-cored transformer

Recall and use the equation for 100% efficiency in a transformer IpVp = IsVs where p and s refer to primary and secondary

Recall and use the equation P = I2R to explain why power losses in cables are smaller when the voltage is greater

Describe the structure of an atom in terms of a positively charged nucleus and negatively charged electrons in orbit around the nucleus

Know how atoms may form positive ions by losing electrons or form negative ions by gaining electrons

Describe how the scattering of alpha (α) particles by a sheet of thin metal supports the nuclear model of the atom, by providing evidence for: (a) a very small nucleus surrounded by mostly empty space (b) a nucleus containing most of the mass of the atom (c) a nucleus that is positively charged

Describe the composition of the nucleus in terms of protons and neutrons

State the relative charges of protons, neutrons and electrons as +1, 0 and –1 respectively

Define the terms proton number (atomic number) Z and nucleon number (mass number) A and be able to calculate the number of neutrons in a nucleus A

Use the nuclide notation Z X

Explain what is meant by an isotope and state that an element may have more than one isotope

Describe the processes of nuclear fission and nuclear fusion as the splitting or joining of nuclei, to include the nuclide equation and qualitative description of mass and energy changes without values

Know the relationship between the proton number and the relative charge on a nucleus

Know the relationship between the nucleon number and the relative mass of a nucleus

Know what is meant by background radiation

Know the sources that make a significant contribution to background radiation including: (a) radon gas (in the air) (b) rocks and buildings (c) food and drink (d) cosmic rays

Know that ionising nuclear radiation can be measured using a detector connected to a counter

Use count rate measured in counts / s or counts / minute

Use measurements of background radiation to determine a corrected count rate

Describe the emission of radiation from a nucleus as spontaneous and random in direction

Identify alpha (α), beta (β) and gamma (γ) emissions from the nucleus by recalling: (a) their nature (b) their relative ionising effects (c) their relative penetrating abilities (β+ are not included, β-particles will be taken to refer to β –)

Describe the deflection of α-particles, β-particles and γ-radiation in electric fields and magnetic fields

Explain their relative ionising effects with reference to: (a) kinetic energy (b) electric charge

Know that radioactive decay is a change in an unstable nucleus that can result in the emission of α-particles or β-particles and/or γ-radiation and know that these changes are spontaneous and random

State that during α-decay or β-decay, the nucleus changes to that of a different element

Know that isotopes of an element may be radioactive due to an excess of neutrons in the nucleus and/or the nucleus being too heavy

Describe the effect of α-decay, β-decay and γ-emissions on the nucleus, including an increase in stability and a reduction in the number of excess neutrons; the following change in the nucleus occurs during β-emission neutron → proton + electron

Use decay equations, using nuclide notation, to show the emission of α-particles, β-particles and γ-radiation

Define the half-life of a particular isotope as the time taken for half the nuclei of that isotope in any sample to decay; recall and use this definition in simple calculations, which might involve information in tables or decay curves (calculations will not include background radiation)

Calculate half-life from data or decay curves from which background radiation has not been subtracted

Explain how the type of radiation emitted and the half-life of an isotope determine which isotope is used for applications including: (a) household fire (smoke) alarms (b) irradiating food to kill bacteria (c) sterilisation of equipment using gamma rays (d) measuring and controlling thicknesses of materials with the choice of radiations used linked to penetration and absorption (e) diagnosis and treatment of cancer using gamma rays

State the effects of ionising nuclear radiations on living things, including cell death, mutations and cancer

Describe how radioactive materials are moved, used and stored in a safe way

Explain safety precautions for all ionising radiation in terms of reducing exposure time, increasing distance between source and living tissue and using shielding to absorb radiation

Know that the Earth is a planet that rotates on its axis, which is tilted, once in approximately 24 hours, and use this to explain observations of the apparent daily motion of the Sun and the periodic cycle of day and night

Know that the Earth orbits the Sun once in approximately 365 days and use this to explain the periodic nature of the seasons

Know that it takes approximately one month for the Moon to orbit the Earth and use this to explain the periodic nature of the Moon’s cycle of phases

Define average orbital speed from the equation

Describe the Solar System as containing: (a) one star, the Sun (b) the eight named planets and know their order from the Sun (c) minor planets that orbit the Sun, including dwarf planets such as Pluto and asteroids in the asteroid belt (d) moons, that orbit the planets (e) smaller Solar System bodies, including comets and natural satellites

Know that, in comparison to each other, the four planets nearest the Sun are rocky and small and the four planets furthest from the Sun are gaseous and large, and explain this difference by referring to an accretion model for Solar System formation, to include: (a) the model’s dependence on gravity (b) the presence of many elements in interstellar clouds of gas and dust (c) the rotation of material in the cloud and the formation of an accretion disc

Know that the strength of the gravitational field (a) at the surface of a planet depends on the mass of the planet (b) around a planet decreases as the distance from the planet increases

Calculate the time it takes light to travel a significant distance such as between objects in the Solar System

Know that the Sun contains most of the mass of the Solar System and this explains why the planets orbit the Sun

Know that the force that keeps an object in orbit around the Sun is the gravitational attraction of the Sun

Know that planets, minor planets and comets have elliptical orbits, and recall that the Sun is not at the centre of the elliptical orbit, except when the orbit is approximately circular

Analyse and interpret planetary data about orbital distance, orbital duration, density, surface temperature and uniform gravitational field strength at the planet’s surface

Know that the strength of the Sun’s gravitational field decreases and that the orbital speeds of the planets decrease as the distance from the Sun increases

Know that an object in an elliptical orbit travels faster when closer to the Sun and explain this using the conservation of energy

Know that the Sun is a star of medium size, consisting mostly of hydrogen and helium, and that it radiates most of its energy in the infrared, visible light and ultraviolet regions of the electromagnetic spectrum

Know that stars are powered by nuclear reactions that release energy and that in stable stars the nuclear reactions involve the fusion of hydrogen into helium

State that: (a) galaxies are each made up of many billions of stars (b) the Sun is a star in the galaxy known as the Milky Way (c) other stars that make up the Milky Way are much further away from the Earth than the Sun is from the Earth (d) astronomical distances can be measured in light-years, where one light-year is the distance travelled in (the vacuum of) space by light in one year

Know that one light-year is equal to 9.5 × 1015 m

Describe the life cycle of a star: (a) a star is formed from interstellar clouds of gas and dust that contain hydrogen (b) a protostar is an interstellar cloud collapsing and increasing in temperature as a result of its internal gravitational attraction (c) a protostar becomes a stable star when the inward force of gravitational attraction is balanced by an outward force due to the high temperature in the centre of the star (d) all stars eventually run out of hydrogen as fuel for the nuclear reaction (e) most stars expand to form red giants and more massive stars expand to form red supergiants when most of the hydrogen in the centre of the star has been converted to helium (f) a red giant from a less massive star forms a planetary nebula with a white dwarf star at its centre (g) a red supergiant explodes as a supernova, forming a nebula containing hydrogen and new heavier elements, leaving behind a neutron star or a black hole at its centre (h) the nebula from a supernova may form new stars with orbiting planets

Know that the Milky Way is one of many billions of galaxies making up the Universe and that the diameter of the Milky Way is approximately 100 000 light-years

Describe redshift as an increase in the observed wavelength of electromagnetic radiation emitted from receding stars and galaxies

Know that the light emitted from distant galaxies appears redshifted in comparison with light emitted on the Earth

Know that redshift in the light from distant galaxies is evidence that the Universe is expanding and supports the Big Bang Theory

Know that microwave radiation of a specific frequency is observed at all points in space around us and is known as cosmic microwave background radiation (CMBR)

Explain that the CMBR was produced shortly after the Universe was formed and that this radiation has been expanded into the microwave region of the electromagnetic spectrum as the Universe expanded

Know that the speed v at which a galaxy is moving away from the Earth can be found from the change in wavelength of the galaxy’s starlight due to redshift

Know that the distance d of a far galaxy can be determined using the brightness of a supernova in that galaxy

Define the Hubble constant H0 as the ratio of the speed at which the galaxy is moving away from the Earth to its distance from the Earth; recall and use the equation v H0 = d

Know that the current estimate for H0 is 2.2 × 10 –18 per second

Know that the equation d 1 = v H0 represents an estimate for the age of the Universe and that this is evidence for the idea that all the matter in the Universe was present at a single point