GCSE SCIENCE A / PHYSICS

Transcription

1 GCSE SCIENCE A / PHYSICS PHHP Mark scheme 4405/4403 June 204 Version:.0 Final

2 Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant questions, by a panel of subject teachers. This mark scheme includes any amendments made at the standardisation events which all associates participate in and is the scheme which was used by them in this examination. The standardisation process ensures that the mark scheme covers the students responses to questions and that every associate understands and applies it in the same crect way. As preparation f standardisation each associate analyses a number of students scripts: alternative answers not already covered by the mark scheme are discussed and legislated f. If, after the standardisation process, associates encounter unusual answers which have not been raised they are required to refer these to the Lead Assessment Writer. It must be stressed that a mark scheme is a wking document, in many cases further developed and expanded on the basis of students reactions to a particular paper. Assumptions about future mark schemes on the basis of one year s document should be avoided; whilst the guiding principles of assessment remain constant, details will change, depending on the content of a particular examination paper. Further copies of this Mark Scheme are available from aqa.g.uk Copyright 204 AQA and its licenss. All rights reserved. AQA retains the copyright on all its publications. However, registered schools/colleges f AQA are permitted to copy material from this booklet f their own internal use, with the following imptant exception: AQA cannot give permission to schools/colleges to photocopy any material that is acknowledged to a third party even f internal use within the centre.

3 MARK SCHEME GCSE Science A / Physics PHHP June 204. General The mark scheme f each question shows: Infmation to Examiners the marks available f each part of the question the total marks available f the question the typical answer answers which are expected extra infmation to help the Examiner make his her judgement and help to delineate what is acceptable not wthy of credit, in discursive answers, to give an overview of the area in which a mark marks may be awarded the Assessment Objectives and specification content that each question is intended to cover. The extra infmation is aligned to the appropriate answer in the left-hand part of the mark scheme and should only be applied to that item in the mark scheme. At the beginning of a part of a question a reminder may be given, f example: where consequential marking needs to be considered in a calculation; the answer may be on the diagram at a different place on the script. In general the right-hand side of the mark scheme is there to provide those extra details which confuse the main part of the mark scheme yet may be helpful in ensuring that marking is straightfward and consistent. 2. Emboldening 2. In a list of acceptable answers where me than one mark is available any two from is used, with the number of marks emboldened. Each of the following bullet points is a potential mark. 2.2 A bold and is used to indicate that both parts of the answer are required to award the mark. 2.3 Alternative answers acceptable f a mark are indicated by the use of. Different terms in the mark scheme are shown by a / ; e.g. allow smooth / free movement. 3. Marking points 3. Marking of lists This applies to questions requiring a set number of responses, but f which candidates have provided extra responses. The general principle to be followed in such a situation is that right + wrong = wrong. Each err / contradiction negates each crect response. So, if the number of err / contradictions equals exceeds the number of marks available f the question, no marks can be awarded. However, responses considered to be neutral (indicated as * in example ) are not penalised. Example : What is the ph of an acidic solution? ( mark) Candidate Response Marks awarded green, red*, 5 3 red*, 8 0 Example 2: Name two planets in the solar system. (2 marks) 3 of 6

4 MARK SCHEME GCSE Science A / Physics PHHP June 204 Candidate Response Marks awarded Neptune, Mars, Moon 2 Neptune, Sun, Mars, Moon Use of chemical symbols / fmulae If a candidate writes a chemical symbol / fmula instead of a required chemical name, full credit can be given if the symbol / fmula is crect and if, in the context of the question, such action is appropriate. 3.3 Marking procedure f calculations Full marks can be given f a crect numerical answer, without any wking shown. However, if the answer is increct, mark(s) can be gained by crect substitution / wking and this is shown in the extra infmation column by each stage of a longer calculation. 3.4 Interpretation of it Answers using the wd it should be given credit only if it is clear that the it refers to the crect subject. 3.5 Errs carried fward Any err in the answers to a structured question should be penalised once only. Papers should be constructed in such a way that the number of times errs can be carried fward are kept to a minimum. Allowances f errs carried fward are most likely to be restricted to calculation questions and should be shown by the abbreviation e.c.f. in the marking scheme. 3.6 Phonetic spelling The phonetic spelling of crect scientific terminology should be credited unless there is a possible confusion with another technical term. 3.7 Brackets (..) are used to indicate infmation which is not essential f the mark to be awarded but is included to help the examiner identify the sense of the answer required. 3.8 Igne / Insufficient / Do not allow Igne insufficient is used when the infmation given is irrelevant to the question not enough to gain the marking point. Any further crect amplification could gain the marking point. Do not allow means that this is a wrong answer which, even if the crect answer is given, will still mean that the mark is not awarded. 4 of 6

5 MARK SCHEME GCSE Science A / Physics PHHP June 204 Quality of Written Communication and levels marking In Question 2 candidates are required to produce extended written material in English, and will be assessed on the quality of their written communication as well as the standard of the scientific response. Candidates will be required to: use good English ganise infmation clearly use specialist vocabulary where appropriate. The following general criteria should be used to assign marks to a level: Level : basic Knowledge of basic infmation Simple understanding The answer is poly ganised, with almost no specialist terms and their use demonstrating a general lack of understanding of their meaning, little no detail The spelling, punctuation and grammar are very weak. Level 2: clear Knowledge of accurate infmation Clear understanding The answer has some structure and ganisation, use of specialist terms has been attempted but not always accurately, some detail is given There is reasonable accuracy in spelling, punctuation and grammar, although there may still be some errs. Level 3: detailed Knowledge of accurate infmation appropriately contextualised Detailed understanding, suppted by relevant evidence and examples Answer is coherent and in an ganised, logical sequence, containing a wide range of appropriate relevant specialist terms used accurately. The answer shows almost faultless spelling, punctuation and grammar. 5 of 6

6 MARK SCHEME GCSE Science A / Physics PHHP June 204 (a) advantage any one from: produce no / little greenhouse gases / carbon dioxide allow produces no / little polluting gases allow doesn t contribute to global warming / climate change allow produce no acid rain / sulphur dioxide reference to atmospheric pollution is insufficient produce no harmful gases is insufficient.4.a high(er) energy density in fuel accept one nuclear power station produces as much power as several gas power stations nuclear power stations can supply a lot of me energy is insufficient long(er) operating life allow saves using reserves of fossil fuels gas disadvantage any one from: produce (long term) radioactive waste accidents at nuclear power stations may have far reaching long term consequences high(er) decommissioning costs long(er) start up time accept waste is toxic accept nuclear f radioactive accept high(er) building costs Question continues on the next page... 6 of 6

7 MARK SCHEME GCSE Science A / Physics PHHP June 204 Question continued... (b)(i) (kwh) allow mark f crect substitution eg c an answer of sces mark (b)(ii) any idea of unreliability, eg wind is unreliable shut down if wind too strong/weak wind is variable reference to weather alone is insufficient.4 (c) any one from: cannot be seen no hazard to (low flying) aircraft / helicopters unlikely to be not damaged / affected by (severe) weather (nmally) no / reduced shock hazard unlikely to be damaged is insufficient safer is insufficient less maintenance is insufficient installed in urban areas is insufficient.4 Total 6 7 of 6

8 MARK SCHEME GCSE Science A / Physics PHHP June 204 Question 2 Marks awarded f this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also refer to the infmation on page 5, and apply a best-fit approach to the marking. Mark 6 spec ref..2a 0 marks Level ( 2 marks) Level 2 (3 4 marks) Level 3 (5 6 marks) No relevant content. Considers either solid gas and describes at least one aspect of the particles. Considers both solids and gases and describes an aspect of each. examples of the points made in the response Considers both solids and gases and describes aspects of the particles. Considers one state and describes aspects of the particles and explains at least one of the properties. Considers both states and describes an aspect of the particles f both and explains a property f solids gases. Solids (particles) close together (so) no room f particles to move closer (so hard to compress) vibrate about fixed point strong fces of attraction (at a distance) the fces become repulsive if the particles get closer particles strongly held together/not free to move around (shape is fixed) Considers both states of matter and describes the spacing and movement / fces between the particles. Explains a property of both solids and gases. extra infmation any explanation of a property must match with the given aspect(s) of the particles. Gases (particles) far apart space between particles (so easy to compress) move randomly negligible/no fces of attraction spread out in all directions (to fill the container) Total 6 8 of 6

9 MARK SCHEME GCSE Science A / Physics PHHP June 204 3(a) infrared / IR crect answer only..a 3(b) any two from: increase the power / watts allow increase the temperature of the oven make the oven hotter c decrease the speed allow leave the biscuits in f longer put biscuits through again increase radiation is insufficient igne changes to the design of the oven 3(c) (inside) surface is a (good) reflect po absber (of IR) igne bounce f reflect surface is a (good) reflect of light does not sce..c, d surface is a (good) reflect of light and infrared / heat does sce (and) outside surface is po emitter (of IR) (so) increases the energy reaching the biscuits allow reduces energy loss makes oven me efficient do not accept no energy losses keeps oven hotter is insufficient Total 6 9 of 6

10 MARK SCHEME GCSE Science A / Physics PHHP June 204 4(a)(i) 440 (sound) waves produced in one second accept vibrations / oscillations f waves.5.i 4(a)(ii) (metres) allow 2 marks f an answer that rounds to allow 2 marks f an answer of allow 2 marks f an answer of j allow mark f crect substitution ie 340 = 440 λ 4(b) (sound is) louder as amplitude is larger do not accept the converse waves are taller is insufficient 3.5.3b higher pitch/frequency as me waves are seen reference to wavelengths alone is insufficient waves are closer together is insufficient Total 8 0 of 6

11 MARK SCHEME GCSE Science A / Physics PHHP June 204 5(a) water moves (from a higher level to a lower level).4.b transferring GPE to KE rotating a turbine to turn a generat accept driving turning spinning f rotating moving is insufficient transferring KE to electrical energy transferring GPE to electrical energy gains mark of the 2 marks available f energy transfers 5(b) (TVs in stand-by) use electricity generating electricity (from fossil fuels) produces CO 2 accept power / energy accept greenhouse gas accept sulfur dioxide 2.4.f (CO 2 ) contributes to global warming accept climate change f global warming accept greenhouse effect if CO 2 given accept acid rain if linked to sulfur dioxide 5(c) a fact other than scientific is given, eg economic, political legal personal choice is insufficient 3.2 Total 8 of 6

12 MARK SCHEME GCSE Science A / Physics PHHP June 204 6(a) air near freezer compartment is cooled loses energy accept air at the top is cold..3a cool air is (me) dense particles close(r) together (than warmer air) do not allow the particles get smaller / condense so (cooler) air falls air (at bottom) is displaced / moves upwards / rises do not allow heat rises accept warm air (at the bottom) rises 6(b) if volume is doubled, energy use is not doubled volume energy not a constant ratio 3..3 crect reference to data, eg 500 is but 630 not (c) accept suitable examples, eg advantage: reduces emissions into atmosphere lower input power uses less energy wastes less energy costs less to run cost of buying installing new fridge is insufficient 3.2 igne reference to size of fridge disadvantage: land fill energy waste in production cost difficulty of disposal transpt costs Total 8 2 of 6

13 MARK SCHEME GCSE Science A / Physics PHHP June 204 7(a) conduction..3 7(b) a 7(c) 500 their 7(b) = 2 x c x 35 crectly calculated sces 2 marks 2 2 allow mark f crect substitution, ie = 2 x c x 35 their 7(b) = 2 x c x 35 J/kg C 7(d) energy lost to surroundings energy needed to warm heater accept there is no insulation (on the copper block) 3..3d do not accept answers in terms of human err po results defective equipment Total 6 3 of 6

14 MARK SCHEME GCSE Science A / Physics PHHP June 204 8(a)(i) 5.88 (watts) an answer of 5.9 sces 2 marks allow mark f crect substitution ie power out 0.42 = 4 allow mark f an answer of d 8(a)(ii) 8.2 allow 4 their 8(a)(i) crectly calculated 2.2.a 8(b)(i) input power/energy would be (much) less (reducing cost of running) accept the converse electricity is insufficient 2.2 (also) produce less waste energy / power accept heat f waste energy (as the waste energy / power) increases temperature of the cabinet so cooler on f less time 8(b)(ii) line graph need to get both parts crect accept scattergram scatter graph 3.2c both variables are continuous allow the data is continuous Question 8 continues on the next page... 4 of 6

15 MARK SCHEME GCSE Science A / Physics PHHP June 204 Question 8 continued... 8(c) number of bulbs used-halogen=24 (LED=) total cost of LED = = accept a comparison of buying costs of halogen 36 and LED total cost of halogen= 24 x x 6.00 = 420 buying cost of halogen is 36 and operating cost is 384 accept a comparison of operating costs of halogen 384 and LED allow f 3 marks the difference in total cost is if the number 24 has not been credited statement based on crect calculations that overall LED is cheaper must be both buying and operating costs an alternative way of answering is in terms of cost per hour: buying cost per hour f LED = = p/ buying cost per hour f halogen = = 0.075p/ a calculation of both buying costs sces mark operating cost per hour f LED = = 0.4p/ operating cost per hour f halogen = = 0.8p/ a calculation of both operating costs sces mark all calculations show a crect unit all units crect sces mark statement based on crect calculations of both buying and operating costs, that overall LED is cheaper crect statement sces mark Total 2 5 of 6

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