Transfer of thermal energy — Paper 3 · IGCSE Physics 0625

4 (a) State two differences between evaporation of water and boiling of water. For Examiner’s 1. … Use 2. … [2] (b) The specific latent heat of vaporisation of water is 2260 kJ / kg. Explain why this energy is needed to boil water and why the temperature of the water does not change during the boiling. … … … … [3] (c) A laboratory determination of the specific latent heat of vaporisation of water uses a 120 W heater to keep water boiling at its boiling point. Water is turned into steam at the rate of 0.050 g / s. Calculate the value of the specific latent heat of vaporisation obtained from this experiment. Show your working. specific latent heat of vaporisation = … [3]

8 marks

Mark scheme: 4 (a) on surface/throughout; no bubbles/bubbles; all temps./b.p.; s.v.p. < at. pressure; svp = at. pressure any two B2 2 (b) energy/work to separate molecules B1 (against) forces of attraction between water molecules B1 2 (to break bonds C1) The k.e./speed of the molecules does not increase B1 1 (c) Wt = mL or 120 x 1 = 0.05 x L C1 L = 120/0.05 C1 L = 2400 J/g A1 3 [8] IGCSE – May/June 2006 0625 03

This question in 0625/31 May/June 2006

5 (a) Fig. 5.1 shows a tank used for evaporating salt solution to produce crystals. For Examiner’s Use evaporating tank steam in salt solution steam out Fig. 5.1 Suggest two ways of increasing the rate of evaporation of the water from the solution. Changes may be made to the apparatus, but the rate of steam supply must stay constant. You may assume the temperature of the salt solution remains constant. 1. … … 2. … … [2] (b) A manufacturer of liquid-in-glass thermometers changes the design in order to meet new requirements. Describe the changes that could be made to (i) give the thermometer a greater range, … [1] (ii) make the thermometer more sensitive. … [1] (c) A toilet flush is operated by the compression of air. The air inside the flush has a pressure of 1.0 × 105 Pa and a volume of 150 cm3. When the flush is operated the volume is reduced to 50 cm3. The temperature of the air remains constant during this process. Calculate the new pressure of the air inside the flush. pressure = … [2]

6 marks

Mark scheme: 5 (a) increase surface area of tank B1 blow air over surface/put in windy place B1 2 (b) (i) capillary tube longer or liquid with lower expansivity B1 (ii) capillary tube thinner/finer or liquid with higher expansivity or bigger bulb B1 2 (c) p1v1 = p2v2 or 1 x 105 x 150 = p2 x50 C1 p2 = 3 x 105 (Pa) A1 2 [6]

This question in 0625/31 May/June 2006

5 (a) Fig. 5.1 shows a copper rod AB being heated at one end. For Examiner’s Use copper rod B A Bunsen burner Fig. 5.1 (i) Name the process by which heat moves from A to B. … (ii) By reference to the behaviour of the particles of copper along AB, state how this process happens. … … [3] (b) Give an account of an experiment that is designed to show which of four surfaces will absorb most heat radiation. The four surfaces are all the same metal, but one is a polished black surface, one is a polished silver surface, one is a dull black surface and the fourth one is painted white. Give your answer under the headings below. labelled diagram of the apparatus readings to be taken one precaution to try to achieve a fair comparison between the various surfaces … … [3]

6 marks

Mark scheme: 5 (a) (i) conduction B1 (ii) particles/atoms/ions vibrate or electrons move and carry energy B1 pass on energy from one particle to the next B1 [3] (b) four surfaces facing one heat source B1 suitable detector e.g. thermometer behind surface-read all 4 B1 precaution e.g. equal distance/time B1 (Can not score last two marks if experiment is totally wrong) [3] [Total: 6]

This question in 0625/31 Oct/Nov 2006

5 Fig. 5.1 shows some apparatus designed to compare the ability of two surfaces to absorb infra-red radiation. surface painted surface dull painted black shiny white Bunsen burner Fig. 5.1 The containers, which are identical, are painted on the outside. One is dull black, the other is shiny white. Both are filled with water, initially at the same temperature. (a) (i) Describe how you would use the apparatus to compare the abilities of the two surfaces to absorb infra-red radiation. … … … … [2] (ii) State the result that you would expect. … [1] (b) The thermometers used have high sensitivity and linear scales. (i) State what is meant by high sensitivity. … … [1] (ii) Explain why a high sensitivity is important for this experiment. … … [1] (iii) State what is meant by a linear scale. … … [1] [Total: 6]

6 marks

Mark scheme: 5 (a) (i) heat for the same time B1 take temps on both thermometers B1 [2] (ii) dull black box temp > white box temp OR black is hotter etc. B1 [1] (b) (i) large expansion/change in reading for small change in temp B1 [1] NOT detect/respond to small temp changes (ii) temperature rise small and/or small difference between them B1 [1] (iii) distance between each degree on scale is the same B1 [1] [Total: 6]

This question in 0625/31 May/June 2007

4 Fig. 4.1 shows a sealed steel cylinder filled with high pressure steam. steam Fig. 4.1 Fig. 4.2 shows the same cylinder much later when all the steam has condensed. water Fig. 4.2 (a) (i) Describe the movement of the molecules in the high pressure steam. … … … [2] (ii) Explain how the molecules in the steam exert a high pressure on the inside walls of the cylinder. … … … [2] (b) Describe, in terms of particles, the process by which heat is transferred through the cylinder wall. … … … [2] (c) When all the steam has condensed, 75 g of water is in the cylinder. Under these high pressure conditions, the specific latent heat of vaporisation of steam is 3200 J / g. Calculate the heat lost by the steam as it condenses. heat = … [2] [Total: 8]

8 marks

Mark scheme: 4 (a) (i) random B1 high speed (between collisions) B1 (ii) hit walls B1 many hits/unit area OR hit hard OR large force OR high energy OR many hits/s OR hit very often B1 (b) particles vibrate (more) OR electrons gain energy B1 particle to particle transfer OR flow of free electrons B1 (c) 75 × 3200 OR ml C1 240 000 J OR 240 kJ OR 2.4 × 105J A1 [Total: 8]

This question in 0625/31 Oct/Nov 2007

5 Fig. 5.1 shows some apparatus which is to be used to compare the emission of infra-red radiation from four differently painted surfaces. this side this side painted dull painted shiny white white water inlet metal box this side this side painted shiny painted dull black black Fig. 5.1 Near the centre of each side is an infra-red detector. The four detectors are identical. A supply of very hot water is available. (a) Describe how you would use this apparatus to compare the infra-red radiation from the four surfaces. … … … [3] (b) Suggest which surface will be the best emitter and which will be the worst emitter. best emitter … worst emitter … [1] (c) The infra-red detectors are made from thermocouples soldered to blackened metal plates. These are connected to galvanometers. In the space below, draw a labelled diagram of a thermocouple. [2] [Total: 6]

6 marks

Mark scheme: 5 (a) take readings of the detectors B1 fill box with water B1 take readings (again) B1 (b) dull black best AND shiny white worst B1 (c) two different metals B1 two junctions (could be at meter) hot and cold need not be indicated B1 any cell, max B1,B0 [Total: 6] IGCSE – October/November 2007 0625 03

This question in 0625/31 Oct/Nov 2007

7 (a) Some water is poured onto a plastic table-top, forming a puddle. The same volume of For water is poured into a plastic dish, which is placed alongside the puddle. This is illustrated Examiner’s in Fig. 7.1. Use water in water in puddle dish Fig. 7.1 Both lots of water begin to evaporate. (i) In terms of the behaviour of molecules, describe what happens during the process of evaporation. … … … … [2] (ii) Explain why the puddle dries out more rapidly than the water in the dish. … … … … [2] (iii) State two changes that would make both lots of water evaporate more rapidly. 1. … 2. … [2] (b) In a place where refrigeration is not possible, a person attempts to keep a bottle of milk For cool by using the procedure illustrated in Fig. 7.2. Examiner’s Use damp cloth bottle milk bowl water Fig. 7.2 Explain in terms of molecules why this procedure would be successful. … … … [3] [Total: 9]

9 marks

Mark scheme: 7 (a) Total penalty for use of ‘particles’ rather than ‘molecules’ is 1 mark. (i) idea of some molecules gaining more KE B1 mols overcome attractive forces OR mols break free of surface B1 (ii) greater area B1 more mols escape (in given time) B1 (iii) increase temperature / supply more heat / make hotter ) blow air across surface, or equiv. ) any 2 B1 + B1 reduce humidity ) decrease pressure ) (b) water evaporates from cloth / water OR faster / more energetic molecules evaporate ) less energetic mols left behind ) energy to evaporate taken from milk ) any 3 B1 × 3 evaporation produces cooling ) idea of cloth always being damp by soaking up water ) [9] IGCSE – May/June 2009 0625 31

This question in 0625/31 May/June 2009

4 (a) Four identical metal plates, at the same temperature, are laid side by side on the ground. For The rays from the Sun fall on the plates. Examiner’s Use One plate has a matt black surface. One plate has a shiny black surface. One plate has a matt silver surface. One plate has a shiny silver surface. State which plate has the fastest-rising temperature when the sunlight first falls on the plates. … [1] (b) The apparatus shown in Fig. 4.1 is known as Leslie’s Differential Air Thermometer. glass bulb radiant heater painted shiny matt black glass bulb air T liquid Fig. 4.1 The heater is switched off. Tap T is opened so that the air on the two sides of T has the same pressure. Tap T is then closed. (i) The heater is switched on. On Fig. 4.1, mark clearly where the two liquid levels might be a short time later. [1] (ii) Explain your answer to (b)(i). … … … [2] [Total: 4]

4 marks

Mark scheme: 4 (a) matt black B1 (b) (i) L down and R up, equal amounts (by eye) B1 (ii) on black side or on left (more) energy / heat absorbed OR greater temp rise OR heats up quicker B1 on black side or on left greater expansion of air / greater pressure of air B1 [4]

This question in 0625/31 May/June 2010

5 A certain substance is in the solid state at a temperature of –36 °C. It is heated at a constant For rate for 32 minutes. The record of its temperature is given in Fig. 5.1. Examiner’s Use time / min 0 1 2 6 10 14 18 22 24 26 28 30 32 temperature / °C –36 –16 –9 –9 –9 –9 32 75 101 121 121 121 121 Fig. 5.1 (a) State what is meant by the term latent heat. … … [2] (b) State a time at which the energy is being supplied as latent heat of fusion. … [1] (c) Explain the energy changes undergone by the molecules of a substance during the period when latent heat of vaporisation is being supplied. … … … [2] (d) (i) The rate of heating is 2.0 kW. Calculate how much energy is supplied to the substance during the period 18 – 22 minutes. energy supplied = … [2] (ii) The specific heat capacity of the substance is 1760 J / (kg °C). For Examiner’s Use the information in the table for the period 18 – 22 minutes to calculate the Use mass of the substance being heated. mass heated = … [3] [Total: 10]

10 marks

Mark scheme: 5 (a) energy / heat required to change state / phase / any example of change of state / phase M1 with no change in temperature / at a specified temperature A1 OR energy to break bonds between molecules /atoms M1 with no change in K.E. A1 (b) any time or range of time between 1.6 (min) and 14.0 (min) inclusive [no UP] B1 (c) turns substance to gas / vapour OR causes evaporation OR escape from liquid C1 energy to break bonds/separate molecules/overcome intermolecular forces Ignore move faster / PE increases A1 (d) (i) Pt / 2 × 4 / 2000 × 4 / 2 × 240 / 2000 × 240 / 8 / 8000 / 480 / 480000 C1 480 000 J OR 480 kJ A1 (ii) (θ =) 43 (°C) seen anywhere C1 Q = mcθ OR 480000 = m x 1760 × 43 in any form ecf. from (i) C1 6.34 kg or 6.3 kg ecf. A1 [10]

This question in 0625/31 May/June 2010

4 A solar panel is mounted on the roof of a house. Fig. 4.1 shows a section through part of the solar panel. sunlight trapped air copper pipe, painted black water glass sheet insulating metal backing sheet, material painted black Fig. 4.1 A pump makes water circulate through the copper pipes. The water is heated by passing through the solar panel. (a) Suggest why (i) the pipes are made of copper, … … [1] (ii) the pipes and the metal backing sheet are painted black, … … [1] (iii) an insulating material is attached to the metal backing sheet, … … [1] (iv) the presence of the glass sheet increases the energy collected by the water. … … [1] (b) During one day, 250 kg of water is pumped through the solar panel. The temperature of this water rises from 16 °C to 38 °C. The water absorbs 25% of the energy falling on the solar panel, and the specific heat capacity of water is 4200 J / (kg °C). Calculate the energy falling on the solar panel during that day. energy = … [4] [Total: 8]

8 marks

Mark scheme: 4 (a) (i) good conductor (of heat) B1 (ignore electricity) (ii) black is good absorber/bad reflector B1 (ignore emitter) (iii) reduce heat lost/conducted away (from pipes/sheet) B1 NOT prevents heat loss o.w.t.t.e. (iv) air heated OR glass reduces/prevents convection OR greenhouse effect OR reference to far and near I.R. OR glass prevents warm air being blown away OR traps air B1 Ignore traps heat (b) 38 – 16 OR 22 C1 mcθ OR 250 × 4200 × his 22 C1 2.31 × 107 (J) e.c.f from previous line C1 9.24 × 107 J OR e.c.f from previous line × 4 correctly evaluated A1 No unit penalty if J seen anywhere in (b) clearly applied to an energy [Total: 8]

This question in 0625/32 Oct/Nov 2010

4 (a) (i) Name the process by which thermal energy is transferred through a metal rod. … [1] (ii) Describe how this process occurs. … … … … [2] (b) An iron rod and a copper rod of equal length are each held by hand at one end, with the other end in the flame from a Bunsen burner, as shown in Fig. 4.1. iron rod copper rod Fig. 4.1 The copper rod becomes too hot to hold much sooner than the iron rod. What does this information tell you about iron and copper? … [1] (c) Gas has to be above a certain temperature before it burns. Fig. 4.2 shows two similar wire gauzes, one made of iron wire and one made of copper wire. Each is held over a Bunsen burner. When the gas supply is turned on and ignited below the gauze, the effect is as shown in Fig. 4.2. copper gauze iron gauze observation: observation: flame appears both flame only above and below appears below the gauze the gauze Fig. 4.2 How can these observations be explained? … … … … … [4] [Total: 8]

8 marks

Mark scheme: 4 (a) (i) conduction B1 (ii) molecules at hot end vibrate more/have high/more energy OR knocked by molecules/free electrons at hot end have more energy B1 energy/vibration transferred to neighbours/shared OR (energetic) electrons move along rod B1 (b) copper is a better conductor OR iron is a poorer conductor (ignore electrical) B1 (c) iron conducts heat slowly OR poor conduction by iron sideways from flame B1 above gauze: flame retains its energy OR gas hot enough to burn B1 copper conducts heat rapidly OR good conduction by copper sideways from flame B1 above gauze: gas not incandescent above gauze OR gas not hot enough to burn B1 [Total: 8]

This question in 0625/33 Oct/Nov 2010

5 (a) Define specific heat capacity. … … [2] (b) Solar energy is striking the steel deck of a ship. (i) Describe how the colour of the deck affects the absorption of the solar energy. … … [1] (ii) The solar energy strikes the deck at the rate of 1400 W on every square metre. The steel plate of the deck is 0.010 m thick. Steel has a density of 7800 kg / m3 and a specific heat capacity of 450 J / (kg °C). 13% of the solar energy striking the deck is absorbed and the rest is reflected. Using these figures, calculate 1. how many joules of solar energy are absorbed by 1.0 m2 of the deck in 1.0 s, number of joules = … [1] 2. the mass of 1.0 m2 of deck, mass = … [2] 3. the rate of rise in temperature of the deck, stating the equation you use. rate of rise = … °C / s [3] [Total: 9]

9 marks

Mark scheme: 5 (a) heat/energy to raise/change temperature M1 of 1 kg/g/unit mass through 1°C/1K/unit temperature A1 (b) (i) darker colours absorb more OR lighter/shiny colours absorb less B1 (ii) 1. 182 B1 2. (mass of 1m2 =) volume × density OR D = M/V OR (1 ×) 0.01 × 7800 C1 78 kg A1 3. Q = mcθ B1 182 = 78 × 450 × θ (e.c.f. from 1,2) C1 0.00519 °C/s OR 5.19 × 10-3 °C/s (e.c.f. from 1,2) A1 [Total: 9] IGCSE – October/November 2010 0625 33

This question in 0625/33 Oct/Nov 2010

11 A mass of 0.36 kg of a certain substance is in the solid state in a well-insulated container. The substance is heated at the rate of 1.2 × 104 J / minute. 2.0 minutes after starting the heating, the substance is all at the same temperature, and it starts to melt. 11.0 minutes after starting the heating, the substance finishes melting and the temperature starts to rise again. (a) Calculate the specific latent heat of the substance. specific latent heat = … [3] (b) (i) After 11 minutes of heating, when the temperature starts rising again, in which state is the substance? … [1] (ii) Describe what happens to the molecules as thermal energy is supplied to them in this state. … … … … [2] [Total: 6]

6 marks

Mark scheme: 11 (a) Pt OR 1.2 × 104 × 9 OR 1.2 × 104 × (11 – 2) C1 (l=) E/m OR E/0.36 OR Pt/m OR Pt/0.36 C1 3 × 105 J/kg A1 (b) (i) liquid ignore vapour/gas/water A1 (ii) move around more rapidly / faster / more KE ignore start to vibrate etc but accept starts to vibrate faster move further apart / spreads out (NOT molecules expand) any 2 B1 break free / evaporate / overcome bonds / overcome forces of attraction /escape / change state (accept boils) convection (current) [6]

This question in 0625/31 May/June 2011

4 Use the information in the table when answering this question. specific heat capacity of ice 2.0 J / (g °C) specific heat capacity of water 4.2 J / (g °C) specific latent heat of fusion of ice 330 J / g specific latent heat of vaporisation of water 2260 J / g (a) Explain what is meant by the statement: ‘the specific latent heat of fusion of ice is 330 J / g’. … … … [1] (b) A block of ice is taken from a freezer at –25 °C, placed in a metal container, and heated by a source of constant power. The graph in Fig. 4.1 shows how the temperature of the contents of the container changes with time. At point E on the graph the container is empty. D E 100 temperature / °C 75 50 25 B C 0 time A –25 Fig. 4.1 (i) State what is taking place in the regions of the graph from B to C, and from D to E. B to C … … D to E … … [2] (ii) Use the information in the table to explain why the line DE is longer than the line BC. … … … [1] (iii) Use the information in the table to explain why the graph is steeper from A to B than from C to D. … … … [2] [Total: 6]

6 marks

Mark scheme: 4 (a) 330 J of heat / energy required to change 1 g of ice to water at constant temperature / at melting point / at 0 degrees C B1 (b) (i) (B to C ice is) changing to water / melting / changing to liquid / changing state B1 (D to E water is) changing to steam / vaporising / boiling / changing to gas B1 (ii) Sp. latent of vaporisation of water is greater than sp. latent of fusion of ice B1 (iii) s.h.c. of ice is less than s.h.c. of water B1 more heat required to raise temperature of water OR rate of temperature rise of water is slower OR temperature rise of water takes longer B1 [6]

This question in 0625/33 May/June 2011

5 Fig. 5.1 shows an X-ray tube. target glass tube fins high speed electron beam black surface vacuum copper rod X-rays Fig. 5.1 In the production of X-rays, the target gets very hot. Thermal energy must be removed from the target. The tube has several design features to enable this to happen. For each of the following types of energy transfer, describe how the design of the tube increases the rate of energy transfer. State where the thermal energy transfer mostly happens, the particular design feature that increases the rate of this transfer, and a brief explanation. (a) conduction where … design feature … explanation … … [3] (b) convection where … design feature … explanation … … [3] (c) radiation where … design feature … explanation … … [3] [Total: 9]

9 marks

Mark scheme: 5 (a) conduction rod / target / anode B1 copper / thickness of rod B1 good conductor / increases amount of conduction (of thermal energy) B1 [3] (b) convection fins B1 large surface area / number of fins / spaces between fins B1 large contact with air / allows air to rise between fins B1 [3] (c) radiation fins / black surface / end of rod B1 black surface / large surface area B1 good emitter / large radiating surface ignore absorber B1 [3]

This question in 0625/32 Oct/Nov 2011

6 (a) (i) In the space below, draw a labelled diagram of the apparatus you would use to measure the specific heat capacity of a liquid. If you choose an electrical method, you must include the circuit. [3] (ii) List the quantities you would need to measure, or previously know, in order to calculate the specific heat capacity of the liquid. … … … … … [3] (b) Some sea water has a specific heat capacity of 3900 J / (kg °C) and a boiling point of 100.6 °C. (i) Calculate the energy required to raise the temperature of 0.800 kg of this sea water from 12.0 °C up to its boiling point. State the equation that you use. energy = … [4] (ii) The energy to raise the temperature in (b)(i) is supplied at the rate of 620 W. Calculate the time taken to raise the sea water to its boiling point. time = … [2] [Total: 12]

12 marks

Mark scheme: 6 (a) (i) electrical method lagged container + lid liquid (allow) water 5 points 3 heater in liquid 4 points 2 heater connected to electrical supply (seen or stated) 3 points 1 voltmeter and ammeter appropriately connected (seen) thermometer B3 OR mixtures method lagged container liquid 5 points 3 hot solid/hot liquid 4 points 2 means of heating hot solid / liquid (seen or stated) 3 points 1 means of weighing hot solid / liquid / use of known mass (seen or stated) thermometer B3 (ii) electrical method initial & final temps of liquid OR temp rise voltmeter reading (however expressed) ammeter reading (however expressed) –1 e.e.o.o. heating time mass of liquid B3 OR mixtures method initial and final temps of liquid OR temp rise initial and final temps of added solid / liquid OR temp drop mass of added solid / liquid –1 e.e.o.o. mass of liquid SHC of added solid / liquid B3 (b) (i) Q = mcθ in any form B1 100.6 – 12 OR 88.6 C1 0.8 × 3900 × 88.6 C1 276 432 J A1 (ii) Q = Wt OR (t =) candidate’s (i)/620 C1 445.858 s ecf (i) A1 [12] IGCSE – October/November 2011 0625 33

This question in 0625/33 Oct/Nov 2011

4 Fig. 4.1 shows a cross-section of a double-walled glass vacuum flask, containing a hot liquid. For The surfaces of the two glass walls of the flask have shiny silvered coatings. Examiner’s Use silvered surfaces vacuum hot liquid Fig. 4.1 (a) Explain (i) why the rate of loss of thermal energy through the walls of the flask by conduction is very low, … … … … (ii) why the rate of loss of thermal energy through the walls of the flask by radiation is very low. … … … … [3] (b) Suggest, with reasons, what must be added to the flask shown in Fig. 4.1 in order to For keep the liquid hot. Examiner’s Use … … … … … [3] [Total: 6]

6 marks

Mark scheme: 4 (a) (i) mention of vacuum OR glass is a poor conductor OR vacuum/gap between walls has no molecules/atoms/particles B1 (ii) surface/silver (of walls) is good reflector/poor absorber (of radiation) B1 surface/silver (of walls) is poor emitter (of radiation) B1 (b) add a stopper/lid/bung/cover/top to reduce/prevent (loss of heat by) convection/ M1 conduction/radiation/evaporation OR to prevent steam/hot vapour leaving B1 made of insulator OR example of insulator to reduce/prevent (loss of heat by) convection/radiation/evaporation OR to prevent steam/hot air leaving B1 [Total 6]

This question in 0625/31 May/June 2013

5 (a) On a hot day, sweat forms on the surface of a person’s body and the sweat evaporates. For Examiner’s Explain, in terms of the behaviour of molecules, Use (i) the process of evaporation, … … … (ii) how this process helps the body to cool down. … … … … … … [3] (b) The temperature of a person of mass 60 kg falls from 37.2 °C to 36.7 °C. (i) Calculate the thermal energy lost from the body. The average specific heat capacity of the body is 4000 J / (kg °C). thermal energy lost = … [2] (ii) The cooling of the body was entirely due to the evaporation of sweat. For Examiner’s Calculate the mass of sweat which evaporated. The specific latent heat of Use vaporisation of sweat is 2.4 × 106 J / kg. mass = … [2] [Total: 7]

7 marks

Mark scheme: 5 (a) (i) and (ii) marked together to maximum of 3 marks (i) molecules escape/leave the liquid/form gas or vapour B1 (ii) evaporation OR heat/(thermal) energy needed for evaporation leaves sweat cooler B1 fast(er) molecules/high(er) energy molecules escape OR slow(er) molecules left behind B1 heat flows from body to warm the sweat (so body cools) B1 (b) (i) (Q =) mc∆θ OR mcT OR 60 × 4000 × 0.50 C1 1.2 × 105 J / 120 kJ A1 (ii) Q = mL in any form OR (m =) Q/L OR either with numbers C1 (m = 1.2 × 105 / 2.4 × 106 =) 0.05 kg e.c.f from (b)(i) A1 [Total 7] IGCSE – May/June 2013 0625 31

This question in 0625/31 May/June 2013

3 Water molecules evaporate from a puddle and escape to the atmosphere. Water molecules For also escape to the atmosphere from water boiling in a kettle. Examiner’s Use (a) State two ways in which evaporation differs from boiling. 1. … … 2. … … [2] (b) This part of the question is about an experiment to determine the specific latent heat of vaporisation of water. (i) Suggest apparatus that will provide thermal energy (heat) and state the readings needed to determine the amount of thermal energy provided. apparatus … … readings … … … [2] (ii) Suggest apparatus required for determining the mass of liquid vaporised and state the readings needed to determine that mass. apparatus … … readings … … … [2] [Total: 6]

6 marks

Mark scheme: 3 (a) any two from: at surface / not within liquid (if other way round must be explicit) B1 at any temperature / not at boiling point (if other way round must be explicit) B1 [2] (evaporation) causes cooling boiling requires a heat source bubbles rising (b) (i) viable heat source clearly described e.g. electrical/immersion heater B1 appropriate readings e.g. V, I, t or P & t or joulemeter readings B1 [2] OR combustion heater but only with some mention of amount of fuel used B1 correct measurement of amount of fuel used B1 (ii) viable mass measuring device clearly described B1 e.g. (top pan) balance/scales appropriate readings B1 [2] e.g. mass of water before and after / change of mass of water OR measuring cylinder B1 volume of water before and after / change of volume of water B1 [Total: 6]

This question in 0625/32 May/June 2013

5 Fig. 5.1 shows a saucepan of boiling water on an electric hotplate. For Examiner’s Use Fig. 5.1 As time passes, thermal energy (heat) is constantly supplied to the water but its temperature remains at 100 °C. (a) State two ways in which boiling differs from evaporation. 1. … … 2. … … [2] (b) Explain, in terms of the water molecules, what happens to the thermal energy supplied to the water as it boils. … … … … [2] (c) Describe an experiment to measure the specific latent heat of steam. You may include a For diagram. Examiner’s Use … … … … … … [4] [Total: 8]

8 marks

Mark scheme: 5 (a) any two of: boiling throughout liquid (evaporation at surface), boiling at one temperature (evaporation at any / all temperature / below boiling point), boiling not affected by draught/area (evaporation is), boiling produces bubbles (evaporation does not). B2 (b) (thermal energy) does work against intermolecular forces / breaks bonds B1 molecules separated/moved apart OR becomes PE B1 (c) apparatus: e.g. kettle AND balance / scales OR steam condensing in water with measuring cylinder / scales AND thermometer B1 two masses determined OR volume/mass condensed B1 determine energy input: e.g. VIt or Pt or mc∆T B1 (le = )Q/m B1 [8]

This question in 0625/33 May/June 2013

5 One side of a copper sheet is highly polished and the other side is painted matt black. For Examiner’s The copper sheet is very hot and placed in a vertical position, as shown as in Fig. 5.1. Use copper sheet matt black side polished side left hand right hand Fig. 5.1 A student places her hands at equal distances from the sheet, as shown in Fig. 5.1. (a) Explain (i) why her hands are not heated by convection, … … [1] (ii) why her hands are not heated by conduction. … … [1] (b) State and explain which hand gets hotter. … … … [2] (c) It is suggested that one side of the copper sheet cools to a lower temperature than the other side. Explain why this does not happen. … … … [2] [Total: 6]

6 marks

Mark scheme: 5 (a) (i) heated air / warm air rises / moves up (not sideways) B1 (ii) air (between plate and hands) is a poor conductor / does not conduct B1 (b) left hand / palm (facing matt black side gets hotter) OR hand facing matt black side (gets hotter) B1 matt black side is a better emitter / radiator (of heat than shiny side) B1 (c) conduction takes place B1 copper a good conductor / conduction is rapid / heat flows to equalise temperature B1 [Total: 6]

This question in 0625/31 Oct/Nov 2013

5 Fig. 5.1 shows two identical metal cans, open at the top, used in an experiment on thermal For energy. The outside of can A is polished and the outside of can B is painted black. Examiner’s Use polished black surface surface can A can B Fig. 5.1 (a) The cans are heated to the same temperature. Predict and explain the relative rates of loss of thermal energy by infra-red radiation from the two cans. … … … … [2] (b) (i) A student is provided with the two cans, a supply of hot water and two thermometers. Describe the experiment he should carry out to test your answer to (a). … … … … … … … … … … [4] (ii) Another student is given the same equipment but finds two polystyrene tiles. For Fig. 5.2 shows the tiles alongside the cans. Examiner’s Use polished black surface surface polystyrene can A can B tiles Fig. 5.2 State how she could use the tiles to improve the experiment, and explain why this is effective. … … … … [2] (c) The two cans are now filled with cold water and placed equal distances from a strong source of infra-red radiation. State and explain which can of water heats up more quickly. … … … … [2] [Total: 10]

10 marks

Mark scheme: 5 (a) black can / B loses heat energy quicker / cools faster OR polished can loses heat energy slower / cools slower M1 black radiates / emits more OR polished radiates / emits less ignore anything about absorption A1 [2] (b) (i) any four from: B4 viable experiment e.g. pour in water and measure temperature ignore methods with external thermometers (for this point only) pour (hot) water into both cans to same level / same amount place thermometers in same position relative to each can / detail relating to stirring thermometers not touching the metal of can observe change of temperature correct detail of timing repeat readings [4] IGCSE – October/November 2013 0625 32 (ii) use tiles as lids M1 reduce convection/evaporation (to room) A1 OR alternative method put tiles under cans (M1) reduce, ignore prevent, conduction (to bench) (A1) for both methods, ignore other modes of heat transfer, ignore place tiles around can [2] (c) black can / B M1 black absorbs (radiation) better, ignore anything about emission A1 [2] [Total: 10] 8

This question in 0625/32 Oct/Nov 2013

1 An archaeologist digging at an ancient site discovers a spoon. The spoon is made from an For unidentified material. Examiner’s Use (a) The archaeologist suspects that the spoon is made of metal. She places it above a flame, as shown in Fig. 1.1. Fig. 1.1 (i) She notices that the handle of the spoon quickly becomes very hot. State why this observation supports the suggestion that the spoon is made of metal. … … [1] (ii) Describe, in terms of its atoms, how thermal energy is transferred through a metal. … … … … … [3] (b) The archaeologist hopes that, by determining its density, she will be able to identify the For metal. Examiner’s Use Describe a method for determining the density of the metal from which the spoon is made. … … … … … … … [4] [Total: 8]

8 marks

Mark scheme: 1 (a) (i) (metals/they are) (good) conductors (of heat) B1 [1] (ii) (at hot end) molecules vibrate (more) or electrons identified as mechanism of conduction B1 molecules collide with their neighbours or electrons move faster/have more energy B1 energy/vibration passed on or electrons pass on energy/reach far end/free to move B1 [3] (b) determine mass of spoon (condone weigh provided word mass is used in answer) B1 immerse spoon in water/liquid B1 determine increase in volume/overflow B1 ρ = m/V or density = mass/volume B1 [4] [Total: 8]

This question in 0625/33 Oct/Nov 2013

5 The Sun is a large sphere of high temperature gas. An extremely large quantity of energy For radiates from the Sun into space every second. Examiner’s Use (a) A process releases energy inside the Sun and its temperature stays high. State the name of this process. … [1] (b) A gardener stores water in a large, cylindrical metal drum. The drum is painted black and has no lid. On a bright, sunny day, the water evaporates quickly and the water level in the drum falls. (i) Suggest how, by using a drum of a different shape, the gardener can reduce the quantity of water lost by evaporation. … … [1] (ii) The gardener is told that, by painting the drum white, he can reduce the quantity of radiation absorbed and so reduce the rate of evaporation. Describe an experiment to show that black surfaces are better absorbers of radiation than white surfaces. You may include a diagram. … … … … … [4] [Total: 6]

6 marks

Mark scheme: 5 (a) (nuclear) fusion B1 [1] (b) (i) smaller (surface) area (accept thinner, narrower(at top), ignore reference to lid) B1 [1] (ii) apparatus: black object, white object, thermometer(s)/ball-bearing with wax/level of water in vessel B1 source of heat e.g. Sun/radiant heater (condone light bulb/Bunsen burner) B1 action: (fill cans with water and) measure temperature rise or wax melts or compare volumes of water B1 observation: water in black can (better absorber) has greater temperature increase / wax melts first / less water note: emission experiment gains max. 2 B1 [4] [Total: 6] IGCSE – October/November 2013 0625 33

This question in 0625/33 Oct/Nov 2013

5 (a) Puddles of water form on a path after rainfall on a windy day. In terms of molecules, state and explain how the rate of evaporation of the puddles is affected by (i) a reduction of wind speed, … … … … [2] (ii) an increase of water temperature. … … … … [2] (b) Fig. 5.1 shows two puddles. large puddle small puddle Fig. 5.1 State and explain how the rate of evaporation from the large puddle compares to that from the small puddle under the same conditions. … … … … [2] (c) Describe an experiment to demonstrate the difference between good and bad emitters of infra-red radiation. You may include a diagram to help your description. State what readings should be taken. … … … … … … [3] [Total: 9]

9 marks

Mark scheme: 5 (a) (i) reduces (rate of evaporation) NOT zero (rate of evaporation) M1 no / fewer evaporated molecules removed by wind OR greater humidity / vapour pressure NOT fewer molecules in liquid / puddle blown away A1 (ii) increases (rate of evaporation) M1 molecules move faster / have more energy OR more molecules have energy to escape A1 (b) greater (rate of evaporation) OR rate is less in small puddle ignore rate of disappearance of puddle B1 surface areas correctly compared B1 IGCSE – May/June 2014 0625 32 (c) description of viable experiment NOT absorption expt M1 statement of measurements to be made A1 good detail e.g. thermometers in comparable positions OR pyrometer same position relative to different surfaces A1 [Total: 9]

This question in 0625/32 May/June 2014

4 Fig. 4.1 shows some of the apparatus that a student uses to determine the specific heat capacity of aluminium. connections to electric circuit electric heater insulating lid thermometer aluminium block insulating container Fig. 4.1 (a) State the measurements the student needs to make, including those from the electric circuit. For each quantity measured, state a symbol. … … … … … … … [4] (b) Use your symbols from (a) to complete the formula used to determine the specific heat capacity c. specific heat capacity c = … [2] (c) Another student performs the experiment without using insulation. He obtains a higher value for c. Explain why this student’s measurements lead to this higher value. … … [1] [Total: 7]

7 marks

Mark scheme: 4 (a) mass of block m B1 initial temperature θ1 and final temperature θ2 B1 time of heating t B1 voltage / p.d. V AND current I B1 (b) (c = ) VIt ÷[m (θ2 – θ1)] OR Pt ÷ [m (θ2 – θ1)] OR E ÷ [m (θ2 – θ1)] as appropriate to symbols defined in (a) numerator correct B1 denominator correct B1 (c) (more) thermal energy / heat lost (to surroundings) so temperature rise is less OR more thermal energy / heat input required for same temperature rise B1 [Total: 7]

This question in 0625/31 Oct/Nov 2014

4 (a) (i) State two ways in which the molecular structure of a liquid is different from the molecular structure of a solid. 1. … … 2. … … [2] (ii) Explain, in terms of energy, the process which takes place as a solid at its melting point changes into a liquid at the same temperature. … … … [1] (b) During a severe snowstorm, a layer of snow (ice crystals) forms on the body of an animal in a field. The snow and the surrounding air are at 0 °C. The snow begins to melt. (i) The mass of snow that falls on the animal is 1.65 kg. The specific latent heat of fusion of snow is 330 000 J / kg. Calculate the thermal energy needed to melt this snow. thermal energy = … [2] (ii) The animal derives energy from its food to maintain its body temperature. State the energy change that takes place. … [1] [Total: 6]

6 marks

Mark scheme: 4 (a) (i) any 2 from: max. B2 • liquid molecules not in fixed positions / can move about / move past each other OR solid molecules have a fixed position • liquid molecules have random arrangement OR solid molecules arranged regularly / in patterns / layers / lattice • liquid molecules are (slightly) further apart (than solid molecules) OR reverse argument (ii) energy / work / thermal energy / (latent) heat required AND to break bonds (between molecules) / to overcome attractive forces (between the molecules) / to increase the potential energy of the molecules B1 (b) (i) E = ml in any form OR ml OR 1.65 × 330 000 C1 = 540 000 J OR 544 500 J A1 (ii) chemical (energy in body) converted to thermal / internal (energy) B1 [Total: 6]

This question in 0625/31 May/June 2015

5 (a) State what is meant by the specific heat capacity of a substance. … … … [2] (b) A student carries out an experiment to find the specific heat capacity of aluminium. He uses an electric heater and a thermometer, inserted into separate holes in an aluminium block. The following data are obtained. mass of aluminium block = 2.0 kg power of heating element = 420 W time of heating = 95 s initial temperature of block = 19.5 °C final temperature of block = 40.5 °C Calculate the value of the specific heat capacity of aluminium given by this experiment. specific heat capacity = … [4] (c) In the experiment in (b), no attempt is made to prevent loss of thermal energy from the surfaces of the block. Suggest two actions the student could take to reduce the loss of thermal energy from the surfaces of the block. 1. … 2. … [2] [Total: 8]

8 marks

Mark scheme: 5 (a) energy/heat required to increase temperature • of 1 kg / 1 g / unit mass (of the substance) B1 • by 1 °C / 1 K / unit temperature B1 (b) E = m c ∆θ in any form OR (c =) E ÷ m ∆θ C1 E = P t in any form OR 420 × 95 (= 39 900) C1 ∆θ = [40.5 – 19.5] OR 21 C1 (c = 39 900÷42 =) 950 J / (kg °C) A1 (c) any two separate points from: max. B2 • lagging / insulation (around block) OR insulate (the block) • raise temperature of block by a smaller amount OR heat for a shorter time OR use lower power heater for same time OR higher power for same temperature rise / shorter time • polish the surface of the block OR wrap the block in shiny material OR paint (shiny) white • reduce initial temperature of block (to below room temperature) OR raise temperature of room • reduce draughts [Total: 8]

This question in 0625/31 May/June 2015

4 A liquid-in-glass thermometer has a linear scale and a range of 120 °C. (a) State what is meant by a linear scale. … … [1] (b) The highest temperature that this thermometer can measure is 110 °C. State the lowest temperature that it can measure. lowest temperature = … [1] (c) A second liquid-in-glass thermometer has the same range but it has a greater sensitivity. Suggest two ways in which the second thermometer might differ from the first. 1. … 2. … [2] (d) A thermometer has a bulb that is painted white and is shiny. It is placed in boiling water for several minutes. It is then removed from the water and is held in air. Fig. 4.1 shows how the thermometer reading changes during the next 8 minutes. 100 temperature / °C 80 60 40 20 0 0 2 4 6 8 time / minutes Fig. 4.1 The bulb of this thermometer is now re-painted so that it has a matt, black surface. The procedure is repeated. (i) On Fig. 4.1, sketch a second line to suggest how the reading of the re-painted thermometer changes during the 8 minutes. [2] (ii) Tick one of the boxes to show how painting the bulb black affects the linearity of the scale, the range and the sensitivity of the thermometer. The linearity, the range and the sensitivity all change. Only the linearity and the range change. Only the linearity and the sensitivity change. Only the range and the sensitivity change. Only the linearity changes. Only the range changes. Only the sensitivity changes. None of these properties changes. [1] [Total: 7]

7 marks

Mark scheme: 4 (a) same distance moved (by thread) for same temperature change B1 (b) – 10 °C B1 (c) any two from: max. B2 • longer stem • bigger bulb OR more liquid • narrower bore OR thinner thread • liquid with greater expansivity (d) (i) falls from 100 °C with a decreasing gradient AND at a faster rate B1 finishes horizontal along 20 °C line B1 (ii) only bottom box ticked B1 [Total: 7]

This question in 0625/33 May/June 2015

5 (a) State what is meant by the specific latent heat of fusion (melting) of a substance. … … [2] (b) Ice cubes of total mass 70 g, and at 0 °C, are put into a drink of lemonade of mass 300 g. All the ice melts as 23 500 J of thermal energy transfers from the lemonade to the ice. The final temperature of the drink is 0 °C. (i) Calculate the specific latent heat of fusion for ice. specific latent heat of fusion = … [2] (ii) The thermal energy that causes the ice to melt is transferred from the lemonade as it cools. The loss of this thermal energy causes the temperature of the 300 g of the lemonade to fall by 19 °C. Calculate the specific heat capacity of the lemonade. specific heat capacity = … [2] (iii) The melting ice floats on top of the lemonade. Explain the process by which the lemonade at the bottom of the drink becomes cold. … … … [2] [Total: 8]

8 marks

Mark scheme: 5 (a) energy/heat needed to change state of substance/melt B1 (from solid to liquid at constant temperature / melting point) per kg / per unit mass B1 (b) (i) (lf=) Q ÷ m in any form: words, symbols, numbers C1 340 J / kg OR 336 J / g OR equivalent in J / kg A1 (ii) (c =) Q ÷ [m ∆T] in any form: words, symbols, numbers C1 4.1 J / (g °C) OR 4100 J / (kg °C) A1 (iii) cold water denser AND sinks B1 convection (current) OR circulation OR warmer water rises B1 [Total: 8]

This question in 0625/33 May/June 2015

7 Fig. 7.1 shows a room with a heater. ceiling of room convector heater Fig. 7.1 (a) The temperature in the room is hottest near to the ceiling. Explain why. … … [2] (b) The ceiling of the room is made from an insulating material as shown in Fig. 7.2. aluminium foil top foam with air trapped inside bottom aluminium foil Fig. 7.2 Explain how this reduces the transfer of thermal energy through the ceiling. … … … … … … [4] [Total: 6]

6 marks

Mark scheme: 7 (a) any two from: B2 • hot air expands / particles move (further) apart • hot air less dense • less dense air rises (b) any four from: B4 • aluminium / foil (on bottom) is a good reflector • infrared / radiation reflected back into room • (trapped) air is a good insulator / poor conductor • (insulation) reduces heat lost by conduction • foam reduces convection currents / prevents air moving • (air cannot move so) prevents heat loss by convection • aluminium / foil (on top) is a poor emitter (so reduces radiation into space above ceiling) [Total: 6]

This question in 0625/32 Feb/March 2016

3 Fig. 3.1 shows a metal plate-warmer. plate of metal food warming-tray handle candle heater Fig. 3.1 The plate-warmer contains two small candle heaters. Plates of food are placed on top of the warming-tray. (a) (i) State the name of a process by which the thermal energy from the candles passes to the warming-tray. … [1] (ii) State the name of the process by which thermal energy moves through the warming-tray. … [1] (b) The outside of the plate-warmer is shiny. Suggest how this helps the plate-warmer to stay hot. … [1] (c) The handles of the plate-warmer are made from metal. Identify a problem with this, and suggest how the problem could be solved. problem: … action: … [2] [Total: 5]

5 marks

Mark scheme: 3(a)(i) convection OR radiation B1 3(a)(ii) conduction B1 3(b) poor emitter OR poor radiator (of thermal energy) B1 3(c) (handles) become hot B1 use an insulator B1 Total: 5

This question in 0625/31 May/June 2016

8 Researchers have found that the best temperature for drinking coffee is 60 °C. A designer has developed a new type of cup for keeping coffee at 60 °C. The cup is shown in Fig. 8.1. plastic lid inner steel walls coffee shiny outer steel wall material Z vacuum Fig. 8.1 Material Z has a melting point of 60 °C. At room temperature, material Z is solid. Coffee, at a temperature of 90 °C, is poured into the cup. The coffee cools rapidly to 60 °C. (a) State what happens to material Z when the hot coffee is poured into the cup. … [1] (b) Explain how the features of the cup enable the coffee to be kept at 60 °C for a long time. plastic lid … … … vacuum … … … shiny outer steel wall … … … material Z … … … … … [5] [Total: 6]

6 marks

Mark scheme: 8(a) (material Z) melts B1 8(b) any five from: (plastic lid) is a good insulator (plastic lid) reduces ( heat loss by) convection (plastic lid) reduces ( heat loss by) evaporation (vacuum) reduces / prevents (heat loss by) convection (vacuum) reduces / prevents (heat loss by) conduction shiny / silver surface is a poor radiator / bad emitter (of thermal energy) at 60 °C material Z solidifies material Z maintains a constant temperature (60 °C) during solidification / internal energy is given out B5 Total: 6

This question in 0625/32 May/June 2016

8 Researchers have found that the best temperature for drinking coffee is 60 °C. A designer has developed a new type of cup for keeping coffee at 60 °C. The cup is shown in Fig. 8.1. plastic lid inner steel walls coffee shiny outer steel wall material Z vacuum Fig. 8.1 Material Z has a melting point of 60 °C. At room temperature, material Z is solid. Coffee, at a temperature of 90 °C, is poured into the cup. The coffee cools rapidly to 60 °C. (a) State what happens to material Z when the hot coffee is poured into the cup. … [1] (b) Explain how the features of the cup enable the coffee to be kept at 60 °C for a long time. plastic lid … … … vacuum … … … shiny outer steel wall … … … material Z … … … … … [5] [Total: 6]

6 marks

Mark scheme: 8(a) (material Z) melts B1 8(b) any five from: (plastic lid) is a good insulator (plastic lid) reduces ( heat loss by) convection (plastic lid) reduces ( heat loss by) evaporation (vacuum) reduces / prevents (heat loss by) convection (vacuum) reduces / prevents (heat loss by) conduction shiny / silver surface is a poor radiator / bad emitter (of thermal energy) at 60 °C material Z solidifies material Z maintains a constant temperature (60 °C) during solidification / internal energy is given out B5 Total: 6

This question in 0625/33 May/June 2016

5 A fisherman notices that the water in a lake is warm and that there is a cool breeze from the land, as shown in Fig. 5.1. cool breeze land warm lake Fig. 5.1 (a) The fisherman tries to explain why there is a cool breeze from the land. The statements below describe his ideas. Put a tick (✓) in the box alongside each correct statement. Air above the surface of the warm lake becomes less dense. Air is a good thermal conductor. Denser water rises to the surface of the lake. The cool breeze occurs as a result of convection. Warmer air rises. Water is a good thermal conductor. [3] (b) As the night gets colder, the fisherman puts on a jacket to keep warm. Explain how the jacket keeps the fisherman warm. … … … … [2] [Total: 5]

5 marks

Mark scheme: 5(a) air above water becomes less dense B1 cool breeze occurs as a result of convection B1 warm air rises B1 5(b) (jacket) traps air B1 air is an insulator OR prevents convection B1 Total: 5

This question in 0625/33 Oct/Nov 2016

9 Fig. 9.1 shows an electric heating element in a beaker containing water. The heating element is switched on. beaker water heating element Fig. 9.1 Explain how thermal energy is transferred throughout the water in the beaker. Use ideas about density and expansion in your answer. … … … … … … [5] [Total: 5]

5 marks

Mark scheme: 9 Any five, in any order, from water heats up B1 molecules gain kinetic energy / move faster / move further apart B1 water expands OR water volume increases B1 density (of water) decreases B1 warm water rises OR cool water falls B1 convection (current) B1 Total: 5

This question in 0625/32 Feb/March 2017

4 A house has white wooden walls and a black wooden door, as shown in Fig. 4.1. white black Fig. 4.1 (a) The Sun is shining on the door and the front wall of the house. (i) State the name of the process by which thermal energy is transferred from the Sun to the Earth. … [1] (ii) Fig. 4.2 shows part of the white wall and the black door of the house. Two thermometers have been attached, one to the wall and the other to the door. thermometer A thermometer B Fig. 4.2 Thermometer A measures the temperature of the white wall. Thermometer B measures the temperature of the black door. The thermometer readings are recorded after the Sun has been shining on the house for some time. Suggest which thermometer has the higher temperature and explain why. higher temperature … explanation … … … … [3] (b) The air conditioning unit inside a room in the house is switched on. The air conditioning unit takes in warm air and gives out cold air, as shown in Fig. 4.3. cold air ceiling air conditioning unit room door Fig. 4.3 Explain how the air conditioning unit cools all the air in the room. … … … … … [3] [Total: 7]

7 marks

Mark scheme: 4(a) radiation B1 4(a)(ii) thermometer near door or B is at higher temperature B1 any 2 from: darker colours are better absorbers (of thermal energy) darker colours are better emitters (of thermal energy) white/lighter colours are better reflectors (of thermal energy) white/lighter colours are poorer absorbers (of thermal energy) white/lighter colours are poorer emitters (of thermal energy) B2 4(b) any 3 from: cold air is denser (than warm air) cold air will fall the cold air is warmed and expands less dense/warm air rises or replaces the cold air (forming a) convection (current) B3 Total: 7

This question in 0625/32 May/June 2017

5 A cup made from plastic, containing a hot drink, is shown in Fig. 5.1. plastic sides hot drink air Fig. 5.1 (a) State the term given to materials that reduce the transfer of thermal energy. … [1] (b) The hot drink gradually cools. Describe and explain two processes by which thermal energy is transferred from the hot drink. … … … … … … … … [5] [Total: 6]

6 marks

Mark scheme: 5(a) insulator B1 5(b) Any five from: conduction / slow or limited transfer of thermal energy molecules move slower / lose kinetic energy convection stated as (drink cools) volume decreases density (of cooler drink) increases cooler water falls evaporation (of hot water) more energetic molecules escape / less energetic molecules remain B5

This question in 0625/32 Oct/Nov 2017

6 Fig. 6.1 shows a liquid-in-glass thermometer. liquid °C –10 0 10 20 30 40 50 60 70 80 90 100 110 Fig. 6.1 (a) (i) Which of these metals is often used for the liquid in thermometers? Tick the correct box. magnesium mercury silver [1] (ii) The thermometer is placed inside a freezer containing ice. Suggest the temperature of the ice. Draw an arrow on Fig. 6.1. [1] (iii) A thermometer is calibrated using two fixed points. State the temperatures of the two fixed points. lower fixed point = … °C upper fixed point = … °C [1] (b) The sentences are about thermal processes. Complete each sentence. Use words from the box. Each word may be used once, more than once or not at all. conductor convection emitter insulator radiation reflection • A dull black surface is a good … • Copper is used to make pans because it is a good thermal … • In fluids, thermal energy is transferred mainly by … • Thermal energy reaches Earth from the Sun by means of … [4] [Total: 7]

7 marks

Mark scheme: 6(a)(i) mercury B1 6(a)(ii) arrow between 0 o C and start of capillary tube B1 6(a)(iii) 0 (oC) AND 100 (o C) B1 6(b) emitter B1 conductor B1 convection B1 radiation B1

This question in 0625/33 Oct/Nov 2017

6 A student constructs a device for absorbing thermal energy from the Sun. Fig. 6.1 shows the device. Sun thermometer Tank A thermometer cold water white plastic pipe Tank B warm water Fig. 6.1 The student places the white plastic pipe in sunlight. The cold water flows slowly from Tank A to Tank B. Energy from the Sun heats the water in the pipe. Fig. 6.2 shows the temperatures in Tank A and Tank B. –10 0 10 20 30 40 50 60 70 80 90 100 110 °C Thermometer showing temperature in Tank A. –10 0 10 20 30 40 50 60 70 80 90 100 110 °C Thermometer showing temperature in Tank B. Fig. 6.2 (a) Determine the rise in temperature of the water. temperature rise = … ° C [1] (b) The student wants to increase the thermal energy absorbed by the water in the pipe. Suggest three improvements he can make to increase the thermal energy absorbed. 1 … … 2 … … 3 … … [3] (c) Describe how the thermal energy is transferred from the Sun to the water inside the pipe. … … [2] [Total: 6]

6 marks

Mark scheme: 6(a) (26 – 23 =) 3(°C) 1 6(b) any three from: use metal pipe paint black or use black pipe use matt or dull (paint) (place) reflector behind pipe use long(er) pipe use pipe with great(er) surface area slow(er) flow rate (place) glass/(clear) plastic cover over pipe 3 6(c) infra-red (radiation through space/air) 1 conduction through pipe 1

This question in 0625/31 May/June 2018

4 A Bunsen burner heats a beaker of water, as shown in Fig. 4.1. thermometer stand beaker water Bunsen burner Fig. 4.1 (a) (i) Fig. 4.2 shows the thermometer used in Fig. 4.1. State the temperature shown on the thermometer. –10 0 10 20 30 40 50 60 70 80 90 100 110 °C Fig. 4.2 temperature = … ° C [1] (ii) The thermometer shown in Fig. 4.2 uses a physical property that changes with temperature. Indicate the measurable property that changes with temperature. Tick one box. expansion of glass expansion of liquid colour of liquid colour of glass [1] (b) Thermal energy (heat) transfers through the bottom of the beaker to the water. State the name given to this process. … [1] (c) Thermal energy transfers throughout the water in the beaker. Describe and explain how this happens. … … … … … [4] [Total: 7]

7 marks

Mark scheme: 4(a)(i) 38 (°C) 1 4(a)(ii) 2nd box ticked i.e. expansion of liquid 1 4(b) conduction 1 4(c) any three from: water is a fluid water molecules gain (kinetic) energy/move faster/further apart water expands/volume increases warm/hot water or molecules rises convection (current created) cooler/cold/water falls/sinks (to be heated again) 3 correct reference to density change of water 1

This question in 0625/32 May/June 2018

6 A student investigates the thermal energy lost from two metal cans, X and Y. The cans are identical apart from their outside colour. The student pours the same volume of hot water into each can and seals each can. The student records the temperature of the water in each can at regular time intervals for a period of 35 minutes. The equipment is shown in Fig. 6.1. thermometer thermometer hot water hot water can X can Y Fig. 6.1 Fig. 6.2 is a graph of the results from the investigation. 80 temperature / °C 60 40 can X can Y 20 0 0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 time / minutes Fig. 6.2 (a) For can X, use Fig. 6.2 to determine the drop in temperature of the water (i) in the first five minutes … [1] (ii) in the last five minutes. … [1] (b) Explain why the water cools at a greater rate during the first five minutes of the experiment, compared with the last five minutes. … … … [2] (c) The outside of one can is dull black and the outside of the other is shiny white. State the colour of can Y. … Explain your answer. … … … [2] [Total: 6]

6 marks

Mark scheme: 6(a)(i) 80 – 56 OR 24(°C) 1 6(a)(ii) 20 – 18 or 2(°C) 1 6(b) water hotter (at start) 1 (so) greater temperature difference (between can and surroundings) 1 6(c) (dull) black 1 greater (rate of) loss of thermal energy (from dark colours) OR black or it is better radiator/emitter (of thermal energy) 1

This question in 0625/33 May/June 2018

6 (a) Some materials are poor conductors of thermal energy (heat energy). State the term that describes materials that are poor conductors of thermal energy. … [1] (b) Some materials are good conductors of thermal energy. Draw a ring around each material that is a good conductor of thermal energy. air aluminium copper glass plastic water [1] (c) A student has two rods made of different materials. The rods are the same size. Describe an experiment to identify which material is the better conductor of thermal energy. You may draw a diagram in the space below. … … … … … … … [3] [Total: 5]

5 marks

Mark scheme: 6(a) insulator(s) B1 6(b) aluminium AND copper B1 6(c) (one end of both rods) placed in same (type of) heat source means of detecting raised temperature e.g. wax covered rods OR pins attached to rods with wax outcome explained e.g. wax melted further / first on better conductor B3

This question in 0625/31 Oct/Nov 2018

6 (a) Fig. 6.1 shows a cross-section of the inside of an electric oven. metal casing glass front heating element Fig. 6.1 The heater is switched on. (i) On Fig. 6.1, draw two arrows to show how thermal energy moves throughout the oven by convection. [2] (ii) Explain how thermal energy moves throughout the oven by convection. Use your ideas about density and expansion. … … … … [3] (iii) Use a word from the box to complete the sentence. conduction expansion insulation radiation Thermal energy travels at the speed of light by … [1] (b) The oven is in a kitchen that is fitted with a smoke detector. Warm, moving air can carry smoke particles. Suggest the best position for the smoke detector in the kitchen. … [1] [Total: 7]

7 marks

Mark scheme: 6(a)(i) arrow upwards from heating element B1 arrow across top OR down on opposite side B1 6(a)(ii) warm air expands B1 (air) becomes less dense B1 (air) rises B1 6(a)(iii) radiation B1 6(b) on ceiling B1

This question in 0625/32 Feb/March 2019

6 Fig. 6.1 shows a metal pan containing water being heated by an electrical heater. water metal pan electrical heater Fig. 6.1 (a) Complete the sentences to describe how thermal energy is transferred. (i) Thermal energy is transferred from the electrical heater to the bottom of the pan by … [1] (ii) Thermal energy is transferred through the bottom of the metal pan by … [1] (iii) Thermal energy is transferred throughout the water by … [1] (b) A student carries out an experiment to determine which surface is the better emitter of thermal energy. She uses two similar metal containers. One of the containers has a dull black surface. The other has a shiny white surface. Fig. 6.2 shows the metal containers on a bench. (i) Suggest a procedure for her experiment. You may add to Fig. 6.2 to assist with your explanation. shiny white dull black surface bench surface Fig. 6.2 … … … … [3] (ii) Predict the result of the experiment described in (b)(i). … … [1] [Total: 7]

7 marks

Mark scheme: 6(a)(i) conduction OR radiation B1 6(a)(ii) conduction B1 6(a)(iii) convection B1 6(b)(i) any THREE from: hot water in each can same volume of water in each can/same temperature thermometer/radiation detector placed near can or seen on labelled diagram thermometer/radiation detector at same distance from each can measure temperature (change) on each thermometer B3 6(b)(ii) bigger / faster temperature change from better emitter B1

This question in 0625/33 May/June 2019

6 (a) Fig. 6.1 shows a liquid-in-glass thermometer. –10 0 10 20 30 40 50 60 70 80 90 100 110 °C Fig. 6.1 (i) State the name of a liquid used in liquid-in-glass thermometers. … [1] (ii) The thermometer is calibrated using two fixed points. State the values of these fixed points. … °C and … °C [1] (b) A student heats some water in a metal can, as shown in Fig. 6.2. water movement metal can of water heat Fig. 6.2 (i) Complete the sentence. Choose a word from the box. conduction convection radiation Thermal (heat) energy moves through the metal can by … [1] (ii) Describe how thermal energy is transferred throughout the water. Include your ideas about density changes. … … … … … … … [3] [Total: 6]

6 marks

Mark scheme: 6(a)(i) mercury or alcohol B1 6(a)(ii) 0 (°C) AND 100 (°C) B1 6(b)(i) conduction B1 6(b)(ii) Any three from: (heat causes) water molecules (to) move further apart OR (hot) water expands / volume increases (hot water) is less dense NOT molecules less dense/expand (so hot / less dense) water rises (and is replaced by cooler / more dense water) convection / current (in water) B3

This question in 0625/32 Oct/Nov 2019

6 Fig. 6.1 shows a liquid-in-glass thermometer. liquid –10 0 10 20 30 40 50 60 70 80 90 100 110 ice point liquid Fig. 6.1 (a) (i) This thermometer is used for measuring temperatures in science experiments. State the unit for measuring temperature. … [1] (ii) On Fig. 6.1, an arrow points to the temperature reading when the thermometer is placed in pure melting ice. This is labelled ice point. On Fig. 6.1, draw an arrow pointing to the temperature reading when the thermometer is at the upper fixed point. Label this arrow steam point. [1] (b) A liquid-in-glass thermometer uses the property of expansion of a liquid to measure temperature. State one other application or consequence of thermal expansion. … … [1] (c) A student is testing how different surfaces absorb radiant heat. The student puts two metal plates in holders and places them on either side of a radiant heater as shown in Fig. 6.2. One plate has a shiny metal side facing towards the heater and the other plate has a dull black side facing towards the heater. A metal disc is attached to each plate using wax. shiny metal radiant dull black surface heater surface metal disc metal disc wax wax 8 cm 10 cm Fig. 6.2 (i) The student turns on the radiant heater and starts a stop-clock. The wax on the plate with a dull black side melts and the metal disc falls off the plate 53 seconds after the stop-clock is started. The metal disc on the plate with a shiny metal side remains attached for another 32 seconds after the metal disc on the first plate falls. Explain why the metal disc on the plate with a dull black side falls before the metal disc on the plate with a shiny metal side. … … … … … [2] (ii) Another student observes the experiment shown in Fig. 6.2 and says that the comparison of the two plates is not fair. Suggest why the experiment is not fair. … … [2] [Total: 7]

7 marks

Mark scheme: 6(a)(i) °C or degrees celcius B1 6(a)(ii) arrow at 100 (labelled steam) B1 6(b) use OR consequence of thermal expansion identified B1 6(c)(i) black is better / best absorber B1 (so) temperature of wax rises faster on black plate B1 6(c)(ii) (for a valid comparison all independent) variables must be the same B1 plates / discs should be equal distances (from heater) (owtte) B1

This question in 0625/31 May/June 2020

6 Fig. 6.1 shows a hot liquid in a vacuum flask. The vacuum flask keeps the temperature of the liquid in the flask constant for a long time. stopper hot liquid shiny silver surface vacuum (space without particles) shiny silver surface Fig. 6.1 (a) Describe how each feature helps to keep the liquid hot for longer. (i) shiny silver surface … … [2] (ii) the vacuum between the silvered surfaces … … … [3] (b) (i) Suggest a material for the stopper that will help to keep the liquid hot for longer. material … [1] (ii) Give a reason for your answer. reason … … [1] [Total: 7]

7 marks

Mark scheme: 6(a)(i) reflects / does not allow transmission of B1 infrared / thermal radiation B1 6(a)(ii) heat loss by conduction cannot take place B1 heat loss by convection cannot take place B1 because particles are needed for conduction and / or convection B1 6(b)(i) non-metal B1 6(b)(ii) metals are good conductors of heat / non-metals are good insulators / poor conductors B1

This question in 0625/32 May/June 2020

6 Fig. 6.1 shows equipment used to demonstrate convection in air. A burning candle is placed beneath glass tube A. glass tube B glass tube A box burning candle glass Fig. 6.1 (a) The arrows in Fig. 6.1 show the directions in which air moves. Explain why the air moves as shown in Fig. 6.1. … … … … [3] (b) A student has four rods of identical size. The rods are made of copper, brass, iron and glass. Describe an experiment to compare thermal conduction along the rods. You may draw a labelled diagram to help with your answer. … … … … … … [3] [Total: 6]

6 marks

Mark scheme: 6(a) air above candle is heated / warms B1 (air becomes) less dense C1 less dense air rises (up tube A) A1 6(b) means of heating one end of rods B1 means of identifying movement of thermal energy along rod B1 method of comparing materials B1

This question in 0625/32 Oct/Nov 2020

6 (a) Fig. 6.1 shows an electric kettle containing cold water. metal cold water heating element Fig. 6.1 The metal heating element heats the water. Explain how thermal energy from the heating element is transferred to all the water in the kettle. … … … … … … [4] (b) Fig. 6.2 shows two similar metal cans. The only difference is the surface. Can A has a dull black surface and can B has a shiny white surface. dull black shiny white surface surface can A can B Fig. 6.2 (i) A student fills each can with hot water. The initial temperature of the water is 85 °C. The student records the temperature of the water in each can every 30 seconds for 10 minutes. Suggest which can of water will cool more quickly. Give a reason for your answer. suggestion … reason … … [2] (ii) Suggest and explain two changes to can B that reduce thermal energy loss to the surroundings. change 1 … … … change 2 … … … [4] [Total: 10]

10 marks

Mark scheme: 6(a) conduction from the element to the water B1 convection B1 warmer water less dense (than colder water) or ra B1 warm water rises / cool water falls B1 6(b)(i) dull black / can A M1 (dull black) better radiator / good radiator better emitter / gives out more radiant heat / emits more infra-red / loses more energy by radiation A1 6(b)(ii) Any two of following pairs: lag / wrap in (named) insulator / cotton wool / polystyrene reduces heat lost by conduction cover in foil reduces heat lost by radiation add lid reduces heat loss by convection / evaporation B4

This question in 0625/33 Oct/Nov 2020

6 (a) Three rods are identical in size and shape, but each rod is made from a different material. On one end of each rod is a pin held in place by wax. The wax melts when it is warm. The rods are placed on a block of wood and heated equally by a Bunsen burner as shown in Fig. 6.1. rods Bunsen pins held burner on by wax block of wood Fig. 6.1 (i) State the process of thermal energy transfer through the rods. … [1] (ii) Explain how the arrangement in Fig. 6.1 can show which rod transfers thermal energy the most quickly. … … … … [2] (b) (i) State the process by which infrared waves transfer thermal energy. … [1] (ii) State the process of thermal energy transfer which does not require a medium. … [1] (c) Fig. 6.2 shows a heater for warming a room. When there is hot water in the heater, the thermal energy of the water transfers to the room. shiny foil heater Fig. 6.2 The shiny foil on the wall increases the efficiency of the heater. Explain how the shiny foil increases the efficiency of the heater. … … … [2] [Total: 7]

7 marks

Mark scheme: 6(a)(i) conduction B1 6(a)(ii) melts wax OR pin falls off C1 first pin to fall (is best conductor) A1 Question Answer Marks 6(b)(i) radiation B1 6(b)(ii) radiation B1 6(c) foil reflects (radiation / infrared / radiant heat) B1 more energy into room (from heater) B1

This question in 0625/33 May/June 2021

7 (a) Fig. 7.1 shows a candle underneath a thin, metal fan. support for fan direction of rotation thin, metal fan candle Fig. 7.1 When the candle starts to burn, the fan starts to rotate around its support. Explain what causes the fan to rotate. … … … [3] (b) Fig. 7.2 shows a bimetallic strip. It is made of two metals, steel and copper, fastened together. The bimetallic strip is straight when the temperature is 25 °C. clamp steel temperature = 25 °C copper Fig. 7.2 Fig. 7.3 shows the bimetallic strip when the temperature is 40 °C. clamp steel temperature = 40 °C copper Fig. 7.3 (i) Draw the bimetallic strip when the temperature is 10 °C. [1] (ii) The bimetallic strip is used in a circuit, as shown in Fig. 7.4. The circuit is in a room. cell electric bell room temperature = 25 °C steel contacts copper Fig. 7.4 The room temperature is 25 °C. State and explain any changes in the circuit as the temperature of the room rises above 40 °C. … … [2] [Total: 6]

6 marks

Mark scheme: 7(a) any three from: convection (currents) (candle) heats air (warm) air less dense (warm) air rises (rising / moving) air pushes on fan B3 7(b)(i) strip curved downwards B1 7(b)(ii) bimetallic strip curves upwards B1 bell rings OR switches circuit on owtte B1

This question in 0625/32 Oct/Nov 2021

5 Fig. 5.1 shows two metal blocks, A and B, which are the same size and made of the same material. Block A has a dull black surface and block B has a shiny white surface. thermometers dull black shiny white surface surface block A block B Fig. 5.1 The starting temperature of both blocks is 80 °C. Fig. 5.2 shows the cooling curve for block A. 100 90 80 temperature / °C 70 60 50 40 30 20 10 0 0 1 2 3 4 5 6 7 8 9 10 11 12 time / min Fig. 5.2 (a) (i) Using Fig. 5.2, determine the change in temperature for block A from 0 to 2 min. … [1] (ii) Determine the final temperature of block A. final temperature = … °C [1] (iii) Explain why block A has a steady final temperature. … … [1] (b) The results for block B are slightly different from the results for block A. (i) Predict the cooling curve for block B by drawing a line on the graph in Fig. 5.2. [3] (ii) Explain why the results for block B are slightly different from the results for block A. … … [1] [Total: 7]

7 marks

Mark scheme: 5(a)(i) 25 (°C) B1 5(a)(ii) 20 (°C) B1 Question Answer Marks 5(a)(iii) (block reaches) room / surrounding temp OR no (net) energy transfer B1 5(b)(i) line starts at 80 (°C) B1 curve with negative gradient always above curve for block A B1 line above 20 (°C) after 10 min B1 5(b)(ii) black better / best emitter ora B1

This question in 0625/33 Oct/Nov 2021

7 (a) State the name for the transfer of thermal energy through a metal. … [1] (b) A metal can contains some water. The metal can is heated as shown in Fig. 7.1. water movement of water metal can heat Fig. 7.1 Describe how thermal energy causes the movement of water shown in Fig. 7.1. … … … … [3] (c) A student places equal masses of water into two metal cans. The cans are identical apart from one having a white outer surface and the other having a black outer surface. The student places the two cans in direct sunlight. The temperature of the water increases in both cans. After 10 minutes, the temperature increase is greater in one of the cans. State and explain which can has the greater increase in temperature. … … [2] [Total: 6]

6 marks

Mark scheme: 7(a) conduction B1 7(b) any three from: convection (heated water) expands (becomes) less dense less dense water rises OR dense(r) water sinks B3 7(c) (dull) black (can) M1 (black) is a better absorber (of thermal radiation) OR white can is a better reflector A1

This question in 0625/32 Feb/March 2022

6 A teacher fills a copper can with solid wax and heats the can. She measures the temperature of the wax every minute. She continues heating once the wax has melted and stops heating when the wax is boiling. (a) (i) State the term used for the process that transfers thermal energy through the copper. … [1] (ii) Fig. 6.1 shows how the temperature of the wax changes as it is heated. 200 temperature of wax / °C 100 0 0 10 20 30 40 time / min Fig. 6.1 Using the graph in Fig. 6.1, determine: 1. the melting point of the wax … °C [1] 2. the boiling point of the wax … °C [1] 3. the time at which the wax starts to boil. … min [1] (b) Describe the molecular structure of the wax in terms of the arrangement, separation and motion of its molecules when it is a solid and when it is a gas. solid wax … … wax as a gas … … [6] [Total: 10]

10 marks

Mark scheme: 6(a)(i) conduction B1 6(a)(ii) 1 80 (°C) B1 2 170 (°C) B1 3 26 (minutes) B1 Question Answer Marks 6(b) (solid:) particles/molecules any three from: (are) fixed in place/position/arrangement regular spacing / pattern / arrangement vibrating close together B3 (gas:) particles/molecules any three from: (are) moving randomly at high speed colliding (with each other/walls) randomly arranged/no pattern (relatively) far apart B3

This question in 0625/31 May/June 2022

5 Fig. 5.1 shows a cross-section of a flask. The flask is used to keep a liquid hot. The flask has two glass walls with a vacuum between them. The surfaces of the glass walls are shiny. plastic cap double-walled glass container hot liquid vacuum shiny surfaces Fig. 5.1 (a) (i) Explain how the shiny surfaces reduce the transfer of thermal energy from the hot liquid. … … [2] (ii) Explain how the vacuum reduces the transfer of thermal energy from the hot liquid. … … [2] (b) Some of the hot liquid is poured out of the flask into a shallow dish. Explain how evaporation causes the liquid to cool. … … … [3] (c) A student uses a microscope to view a small particle in the liquid. Fig. 5.2 shows the path of the particle. small particle Fig. 5.2 (i) State the name given to the motion of the small particle. … [1] (ii) Explain why the small particle moves as shown in Fig. 5.2. … … [2] [Total: 10]

10 marks

Mark scheme: 5(a)(i) (shiny surfaces) are good reflectors OR poor absorbers/emitters B1 so less thermal energy lost by radiation B1 5(a)(ii) less (heat lost by) convection B1 less (heat lost by) conduction B1 5(b) more energetic particles B1 particles escape (from the surface (attraction)) B1 so average energy of particles remaining (in liquid) decreases B1 5(c)(i) Brownian (motion) B1 5(c)(ii) any two from: (fast moving liquid) molecules bombard/collide with (small) particle collisions produce (resultant) force (in random directions) B2

This question in 0625/32 May/June 2022

5 An engineer makes a device that absorbs thermal energy from the Sun. The absorbed energy heats water. In the device, cold water flows slowly from an upper tank, through a white plastic pipe, to a lower tank. Energy from the Sun heats the water as it flows, as shown in Fig. 5.1. upper cold water tank Sun white plastic pipe lower tank warm water Fig. 5.1 (a) The engineer measures the temperature of the water in each tank. State the name of the instrument used for measuring temperature. … [1] (b) (i) State the name of the process that transfers thermal energy from the Sun to the white plastic pipe. … [1] (ii) State the name of the process that transfers thermal energy through the plastic wall of the pipe to the water inside the pipe. … [1] (c) The engineer wants to increase the thermal energy absorbed by the water in the pipe. Suggest two improvements he can make to increase the thermal energy absorbed. In each case, explain why the suggestion increases the thermal energy absorbed. improvement 1 … … explanation … … improvement 2 … … explanation … … [4] [Total: 7]

7 marks

Mark scheme: 5(a) thermometer B1 5(b)(i) radiation B1 5(b)(ii) conduction B1 5(c) (dull) black pipes B1 better absorber (of radiation)/less reflection from pipes B1 foil/shiny metal behind pipes B1 reflects (radiation back to pipes) owtte B1 valid alternatives (B1)

This question in 0625/33 May/June 2022

4 Fig. 4.1 shows students walking to school. There are puddles of water on the ground. puddles Fig. 4.1 After school, the puddles have disappeared and the ground is dry. (a) (i) State the name of the process that causes the puddles to disappear. … [1] (ii) Describe the process that causes the puddles to disappear. Use your ideas about molecules. … … … [3] (b) A student designs a container to keep a hot liquid at a high temperature. The container is shown in Fig. 4.2. liquid container made of cardboard Fig. 4.2 He finds that the liquid cools too quickly. Suggest two improvements to the design of the container which reduce the transfer of thermal energy from the hot liquid to its surroundings. For each suggestion, state the thermal transfer process that it reduces. suggestion 1 … … thermal transfer process … suggestion 2 … … thermal transfer process … [4] [Total: 8]

8 marks

Mark scheme: 4(a)(i) evaporation B1 4(a)(ii) any three from the following: B3 at the surface more energetic molecules escape (from liquid) owtte (as they) overcome / break forces / bonds (between molecules) (liquid (molecules) →) gas / vapour (molecules) 4(b) any two pairs B2 (surround container with) insulation / lagging / cotton wool or similar – conduction change material of cup to better insulator – conduction (surround container with) foil / silver / (paint) shiny white – radiation (surround container with) vacuum – conduction OR convection lid – evaporation / convection

This question in 0625/32 Oct/Nov 2022

4 A student has a block of solid metal at room temperature. (a) (i) Describe the arrangement, separation and motion of the particles in the solid metal. … … … … [3] (ii) The student cools the block of metal in a freezer. State the effect, if any, of cooling on the kinetic energy of the particles in the block of metal. … [1] (b) (i) State the name of the temperature at which particles have the least kinetic energy. … [1] (ii) State the value of temperature at which particles have the least kinetic energy. Include the unit. … [1] (c) The metal block emits thermal radiation from its surface. State two features of a surface that is a good emitter of thermal radiation. 1 … 2 … [2] [Total: 8]

8 marks

Mark scheme: 4(a)(i) any three from:  (particles are) fixed in position / place  regular arrangement  vibrating  close(r than in liquids or gases) B3 4(a)(ii) (kinetic energy) decreases B1 4(b)(i) absolute zero B1 4(b)(ii) –273 °C OR 0 K OR zero K / kelvin B1 4(c) black OR dark (colour) B1 dull OR rough (surface) B1

This question in 0625/32 May/June 2023

3 Fig. 3.1 represents the arrangement and separation of particles in a liquid. Each circle represents a particle. Fig. 3.1 (a) In the box in Fig. 3.2, draw at least four circles to show the arrangement and separation of particles in a gas. Fig. 3.2 [2] (b) Describe the arrangement, separation and motion of particles in a solid. … … … [3] (c) Fig. 3.3 shows a fire heating water in a metal pan. water metal pan Fig. 3.3 (i) State the name of the process of thermal energy transfer through the metal of the pan. … [1] (ii) Describe how thermal energy is transferred through the water by convection. … … … [3] (iii) State the temperature at which the water boils at standard atmospheric pressure. temperature = … °C [1] [Total: 10]

10 marks

Mark scheme: 3(a) at least 4 circles widely separated (gaps at least the diameter of circles) B1 random arrangement B1 3(b) any three from: B3 regular / uniform arrangement fixed (positions) vibrating close(ly) OR tight(ly) (packed) 3(c)(i) conduction B1 3(c)(ii) any three from: B3 water particles (at bottom of pan) gain thermal / internal / kinetic energy (water) particles move apart density of liquid decreases OR liquid becomes less dense less dense liquid rises causing liquid to circulate (in pan) 3(c)(iii) 100 (°C) B1

This question in 0625/31 Oct/Nov 2023

6 (a) Fig. 6.1 shows a cold drink in a thermal jug. The jug reduces thermal energy transfer from the surroundings to the drink. hinged lid ice vacuum (empty space) plastic casing cold drink Fig. 6.1 State the names of the two processes of thermal energy transfer that are prevented by the vacuum. Explain how the vacuum prevents these two processes of thermal energy transfer. processes … and … explanation … … [2] (b) Fig. 6.2 represents a demonstration that shows how water moves when heated. The colour from the crystal shows the flow of the water. colour from the crystal glass tube coloured crystal water Fig. 6.2 The arrows in Fig. 6.2 show the direction of flow of water in the glass tube when the water is heated. Explain why the water moves in this way. Use your ideas about density. … … … … [4] [Total: 6]

6 marks

Mark scheme: 6(a) conduction AND convection B1 need a medium / particles (to transfer energy) B1 6(b) any four from: B4 water particles gain thermal energy / KE (water) particles move apart warm water becomes less dense less dense water rises / more dense water falls (forming a) convection (current)

This question in 0625/32 Oct/Nov 2023

4 (a) Fig. 4.1 shows a pan on a hotplate. The hotplate heats the pan and the water. shiny sides wooden handle water hotplate copper base Fig. 4.1 Use your ideas about thermal energy transfer to explain why the pan has: (i) a wooden handle … [1] (ii) shiny sides … … [2] (iii) a copper base. … [1] (b) Fig. 4.2 shows a heater for warming a room. When there is hot water in the heater, thermal energy transfers from the water to the room. heater Fig. 4.2 Explain how thermal energy from the heater warms the entire room. Use your ideas about the density of air. You may draw on Fig. 4.2. … … … … [4] [Total: 8]

8 marks

Mark scheme: 4(a)(i) reduces heat transfer (to handle) OR wood is an insulator B1 4(a)(ii) poor / worst emitter (of heat) B1 (of) infrared / radiation B1 4(a)(iii) allows heat transfer (to water) OR (good) conductor (of heat) B1 4(b) any four from: B4 conduction (through metal of heater) air particles gain kinetic energy / KE air particles move further apart hot air becomes less dense hot / less dense air rises OR cold / denser air falls idea of convection current

This question in 0625/33 Oct/Nov 2023

5 Fig. 5.1 shows a metal container used for storing petrol. There is some petrol gas above the liquid petrol inside the metal container. Sun sunlight gas liquid outside of tank is a shiny white surface Fig. 5.1 (not to scale) (a) Describe the arrangement and motion of the particles in the liquid petrol stored in the container. Use your ideas from the kinetic particle model of matter. … … … … [2] (b) The temperature of the petrol gas inside the metal container increases. State and explain any change in the pressure of the petrol gas on the metal container. … … … … [3] (c) Describe how thermal energy travels from the Sun to the petrol inside the metal container. … … [2] [Total: 7]

7 marks

Mark scheme: 5(a) any two from: B2 • (particles are;) random arrangement / pattern • close together OR idea slightly further apart than in solid • move randomly OR move around / about (freely) • colliding with each other / walls • have some vibrational energy / motion 5(b) pressure increases B1 any two from: (because) B2 • particles move faster OR have increased kinetic energy • more (frequent) collisions (with walls of container) • harder collisions (with walls of container) 5(c) infrared OR radiation (through space and atmosphere) B1 conduction (through the metal) B1

This question in 0625/32 Feb/March 2024

6 A student wants to compare the conduction of thermal energy through rods made of iron, copper, glass and aluminium. Each rod is coated with wax. Fig. 6.1 shows the equipment that the student uses. wax coating iron rod copper rod glass rod aluminium rod Bunsen burner heat-proof mat tripod stand Fig. 6.1 (a) Describe how the student can compare the conduction of thermal energy through the rods in Fig. 6.1. … … … [2] (b) The Bunsen burner emits infrared waves. The infrared waves have a wavelength of 2.0 × 10– 6 m. The velocity of the infrared waves is 3.0 × 108 m / s. (i) Calculate the frequency of the infrared waves. frequency = … Hz [3] (ii) State the name of a region of the electromagnetic spectrum which has a wavelength longer than the wavelength of infrared. Give one use of the radiation in this region. region … use … [2] [Total: 7]

7 marks

Mark scheme: 6(a) idea of measure / read / note / compare how much wax melts (along each rod) OR how quickly the wax melts B1 idea of: the better the conductor the shorter the length of unmelted wax (remaining) OR the better the conductor the further the wax melts (along rod) OR the better the conductor the shorter the time for the wax to melt B1 6(b)(i) (frequency =) 1.5  1014 (Hz) A3 (frequency =) 3(.0)  108 ÷ 2(.0)  10–6 (C2) velocity = frequency  wavelength (C1) 6(b)(ii) (region) microwaves OR radio waves B1 valid use that is consistent with radiation in stated region B1

This question in 0625/31 May/June 2024

5 Fig. 5.1 represents an arrangement for heating water. The hot water is stored in the metal container. hot water flows out of the container water metal container electric heater cold water flows into the container Fig. 5.1 (not to scale) (a) Explain why the hot water is available at the top of the container. Use ideas about density. … … … … [3] (b) The electric heater is switched on for one hour every morning. (i) State the name of the process that transfers thermal energy through the walls of the metal container. … [1] (ii) Suggest one way of keeping the water hot after the heater is switched off. … … [1] [Total: 5]

5 marks

Mark scheme: 5(a) convection (current) B1 any two from:  (heated water) expands  (becomes) less dense  (less dense) water rises B2 5(b)(i) conduction B1 5(b)(ii) insulate / lag container owtte B1

This question in 0625/33 May/June 2024

6 Fig. 6.1 shows a wood burner in a cabin. The wood burner keeps the inside of the cabin warm when it is cold outside. chimney shiny foil wood burner Fig. 6.1 (a) Explain how thermal energy from the wood burner warms the cabin by convection. Use your ideas about the density of air. You may draw on Fig. 6.1 as part of your answer. … … … … … [3] (b) (i) The outer surface of the chimney is dull and black. Explain how the dull black surface helps to warm the cabin. … … … [2] (ii) There is shiny foil on the wall. Explain how the shiny foil helps to warm the cabin. … … … … [2] [Total: 7]

7 marks

Mark scheme: 6(a) (heated air) expands B1 (becomes) less dense B1 less dense air rises OR denser air sinks B1 6(b)(i) (dull black is) best / better / good emitter owtte B1 of radiation / infrared B1 6(b)(ii) (shiny foil is) best / better / good reflector M1 of radiation / infrared A1

This question in 0625/32 Oct/Nov 2024

5 (a) Table 5.1 defines three specific temperatures. (i) Complete Table 5.1 by writing the correct temperature for each definition. Table 5.1 definition temperature / °C pure water boiling at standard atmospheric pressure pure ice melting at standard atmospheric pressure the lowest possible temperature of matter [3] (ii) The temperature of air in a room is 15 °C. Calculate the temperature of the air in kelvin. temperature = … K [2] (b) A teacher demonstrates thermal energy transfer through some metal rods. Fig. 5.1 shows the arrangement. metal rods Bunsen burner block of wood pins held on by wax Fig. 5.1 The metal rods are placed on a block of wood. The demonstration compares how quickly thermal energy is transferred to the wax at the end of each rod. (i) State the name of the process for thermal energy transfer through the metal rods. … [1] (ii) The rods are made from different metals. The rods have the same length and diameter. The ends of the rods in the Bunsen flame are at the same temperature. State how the demonstration shows which metal transfers thermal energy at the greatest rate. … … [2] (c) A playground includes a concrete area with white and black squares, as shown in Fig. 5.2. Fig. 5.2 The Sun shines on the concrete area during the day. The temperature of the concrete area increases. During the afternoon, students compare the temperature of the white squares with the temperature of the black squares. State and explain whether the white squares or the black squares have the higher temperature. Include the name of the process of thermal energy transfer from the Sun to the squares. … … … [2] [Total: 10]

10 marks

Mark scheme: 5(a)(i) B1 pure water boiling at standard atmospheric pressure 100 B1 pure ice melting at standard atmospheric pressure 0 the lowest possible temperature of matter –273 B1 5(a)(ii) 288 (K) A2 273 + 15 (C1) 5(b)(i) conduction B1 5(b)(ii) first wax to melt or first pin to fall off or the faster the pin falls off M1 the better the conductor / energy transfer / has the greatest rate A1 5(c) black (square) B1 AND either black – best/good absorber OR worse / poor reflector OR B1 white – best/good reflector OR worse / poor absorber of radiation / infrared (radiation)

This question in 0625/33 Oct/Nov 2024

6 A student warms some water in a metal container using an electric heater, as shown in Fig. 6.1. water metal container electric heater (hotplate) Fig. 6.1 (a) Describe the arrangement, separation and motion of the particles in liquid water. … … … … [3] (b) State how thermal energy moves through the metal container from the heater to the water. … [1] (c) Describe how thermal energy spreads throughout the water. … … … … [3] (d) The water is heated until it is boiling. The air pressure in the room is standard atmospheric pressure. State the temperature at which the water boils. temperature = … °C [1] [Total: 8]

8 marks

Mark scheme: 6(a) any three from (particles are:) B3 in a random arrangement close together OR slightly further apart than in solids move freely OR slide over each other collide (with each other) moving randomly 6(b) conduction B1 6(c) any three from: B3 convection idea that water at bottom of pan is warmed / temp of water at bottom increases warm water is less dense less dense / warm water rises OR more dense/colder water sinks 6(d) 100 (°C) B1

This question in 0625/32 Feb/March 2025

5 (a) A student uses the apparatus in Fig. 5.1 to compare how different surfaces absorb infrared radiation. thermometer thermometer dull black metal container metal container surface shiny white surface air air Bunsen burner Fig. 5.1 There are two metal containers. One has a dull black surface and the other has a shiny white surface. Before heating, the air inside the metal containers is at the same temperature. The Bunsen burner flame is the same distance from each metal container. The Bunsen burner flame emits infrared radiation and heats the metal containers for three minutes. Explain the difference between the temperatures of the air inside the two metal containers after heating for three minutes. … … … … … [2] (b) A teacher has some equipment for comparing thermal conductivity. The teacher has four metal rods and one glass rod. The metals are brass, copper, iron and steel. All five rods are the same size and shape. Describe how the teacher may use the rods to compare the thermal conductivity of the five materials. You may draw a labelled diagram as part of your answer. … … … … … … [4] [Total: 6]

6 marks

Mark scheme: 5(a) black container / air has higher temperature OR black container / air is hotter OR black container / air heats (up) fastest M1 (because) black is a better / good absorber (of infrared radiation) A1 5(b) idea of heating one end of (each) rod B1 method of comparing conduction along rods B1 idea of how to compare: B1 the better the conductor, the shorter the length of unmelted wax (remaining) OR wax melts furthest (along rod) OR which wax melts in the shortest time detail: B1 any one from: • use of same Bunsen flame (at same time) • use of timer for each separate rod • pins attached at same distance from end of rod • rods have {same thickness of wax} / {even coat with wax} / {same length of wax}

This question in 0625/31 May/June 2025

6 (a) A teacher uses the equipment shown in Fig. 6.1. dull black shiny white surface surface thermometer X thermometer Y bottle Fig. 6.1 The thermometers X and Y are the same distance from the bottle. The room temperature is 20 °C. The teacher pours very hot water into the bottle. After 5 minutes, the teacher observes the reading on each thermometer. The reading on thermometer X is 24 °C. (i) The reading on thermometer Y is not 24 °C. Explain why the readings on the two thermometers are not the same. … … … … [2] (ii) Suggest a value for the reading on thermometer Y. thermometer Y reading = … °C [1] (b) A student demonstrates convection in a liquid. The student has a water supply and the following equipment: a candle, a glass beaker, a tripod and some coloured crystals. The coloured crystals dissolve in warm water. tripod glass beaker coloured crystals candle Fig. 6.2 Describe how the student can demonstrate convection in a liquid by using the equipment shown in Fig. 6.2. You may draw a diagram as part of your answer. … … … … … … [4] [Total: 7]

7 marks

Mark scheme: 6(a)(i) dull / black better / best emitter / radiator M1 of infrared (radiation) A1 6(a)(ii) 20  value  24 (C) e.g. 21 OR 22 OR 23 OR 20.5 etc. B1 6(b) place crystals at bottom of (glass) beaker B1 any two from: B2 • (pour) water into (glass) beaker • place beaker on tripod • heat water / beaker with candle observe motion of coloured water / crystals B1

This question in 0625/32 May/June 2025

6 (a) A teacher uses the equipment shown in Fig. 6.1. dull black shiny white surface surface thermometer X thermometer Y bottle Fig. 6.1 The thermometers X and Y are the same distance from the bottle. The room temperature is 20 °C. The teacher pours very hot water into the bottle. After 5 minutes, the teacher observes the reading on each thermometer. The reading on thermometer X is 24 °C. (i) The reading on thermometer Y is not 24 °C. Explain why the readings on the two thermometers are not the same. … … … … [2] (ii) Suggest a value for the reading on thermometer Y. thermometer Y reading = … °C [1] (b) A student demonstrates convection in a liquid. The student has a water supply and the following equipment: a candle, a glass beaker, a tripod and some coloured crystals. The coloured crystals dissolve in warm water. tripod glass beaker coloured crystals candle Fig. 6.2 Describe how the student can demonstrate convection in a liquid by using the equipment shown in Fig. 6.2. You may draw a diagram as part of your answer. … … … … … … [4] [Total: 7]

7 marks

Mark scheme: 6(a)(i) dull / black better / best emitter / radiator M1 of infrared (radiation) A1 6(a)(ii) 20  value  24 (C) e.g. 21 OR 22 OR 23 OR 20.5 etc. B1 6(b) place crystals at bottom of (glass) beaker B1 any two from: B2 • (pour) water into (glass) beaker • place beaker on tripod • heat water / beaker with candle observe motion of coloured water / crystals B1

This question in 0625/33 May/June 2025

8 (a) A coal-fired power station is far from a city. The electricity generated by the power station is transmitted to the city at a high voltage. State two advantages of high-voltage transmission of electricity. 1 … 2 … [2] (b) In the city, transformers reduce the high voltage. Fig. 8.1 shows one of these transformers. transformer black cooling fins ground Fig. 8.1 Transformers become hot when they reduce the high voltage. There are black cooling fins on the casing which contains the transformer. Explain why the fins are black. … … [2] (c) Describe the construction and materials of a simple step-down transformer. You may draw a labelled diagram as part of your answer. … … … [3] [Total: 7]

7 marks

Mark scheme: 8(a) any two from: B2 • smaller current (in cables) • more efficient • less power / heating losses • thinner / cheaper cables / pylons further apart owtte • less voltage drop • allows for transmission over a longer distance • fewer / larger power stations can supply more area / whole country 8(b) (black is a) good / best emitter M1 of thermal radiation / infrared A1 8(c) any three from: B3 • two coils • copper wire / coils • (coils wrapped round / linked by soft) iron core • more turns on primary coil

This question in 0625/33 Oct/Nov 2025