ONE mark may be awarded for a response

Transcription

1 1. (a) Award TWO marks for all four statements correctly classified: 2 The pictures show that as the corn pops, it... or gets bigger. changes to a darker colour changes shape. gets smoother. True False If you are unable to award two marks, award ONE mark for any two or 1 three statements correctly classified. (b) Award ONE mark for: 1 Sasha should measure the temperature. (c) Award ONE mark for: 1 heat (d) Award ONE mark for identifying/ describing a non-reversible change 1 where a new material is produced, eg: (wood/paper/candle) burning; egg being boiled; mixing vinegar and bicarbonate of soda; cooking a cake/biscuits; making a cake; boiling rice/spaghetti; making paper from wood/trees. Give credit for a correct response that goes beyond the key stage 2 programme of study which names a chemical change: combustion; corrosion/rusting; respiration/photosynthesis. ONE mark may be awarded for identifying a biological non-reversible change: an apple decaying/going rotten; a seed growing into a plant. ONE mark may be awarded for a response John Buchan Middle School 1

2 identifying a material and what it changes into: changing bread into toast; paper to ashes; a grape turning into a raisin; milk turning into cheese; changing sand to glass. heating food [heating may not result in an irreversible change]; boiling. response explicitly relating to popcorn: the popcorn cannot change back to seeds again. response naming a non-reversible physical process in which the material is not changed: breaking a cup/glass; dropping an egg; ripping paper; popping a balloon. response identifying a new material without identifying the change: a cake is non-reversible; candle [the wax burns and melts] chips; toast. [5] 2. (a) Award ONE mark for: 1 new materials made by burning John Buchan Middle School 2

3 (b) Award ONE mark for describing a safety precaution that is shown in the picture: 1 she is using tongs; the metal dish stops fire spreading; the tray and sand (do not burn); the short/small candle/nightlight is less likely to fall over; she uses a safe flame; there is sand around the candle. Allow: use soil in the dish [in place of sand]; sand/(metal) dish/tongs. response indicating an alternative method of keeping safe that is not shown in the picture: she wears goggles; the teacher does the experiment. (c) Award ONE mark for correctly completing the table: 1 Material Does it burn? Is the change reversible? wood yes No bread yes No (d) Award TWO marks for correctly identifying the only two materials that will burn:2 cardboard [given] cotton wool or newspaper If you are unable to award two marks, award ONE mark for correctly identifying one of the materials. [5] John Buchan Middle School 3

4 3. (a) Award ONE mark for both rows of the table completed correctly: 1 Material/Object Flexible Hard Transparent aluminium foil wax candle wooden rolling pin plastic food wrap glass (b) Award ONE mark for describing a use of foil that requires it to be flexible: 1 wrapping up food; to bend it around food. ONE mark may be awarded for describing a use of foil where the need for it to be flexible is implied: to cook a chicken in it; to put your sandwiches in; to seal take-away cartons; covering oven dishes. property that gives a use unrelated to being flexible: it does not burn in the oven. (c) Award TWO marks for all three correct boxes ticked: 2 cooling water freezing water into ice dissolving salt in water or If you are unable to award two marks, award ONE mark for ticking any two 1 of the correct boxes. John Buchan Middle School 4

5 (d) (i) Award ONE mark for: 1 condensation. (ii) Award ONE mark for a response indicating that the water inside 1 the pan evaporates: the water evaporates; the water inside the pan turns to water vapour (when the water boils); it changes to a gas. ONE mark may be awarded for an observation implying the water evaporates: the water turns to steam. Do not give credit for a response that includes incorrect science indicating the gas will disappear: the water will turn to water vapour which disappears. the water disappears; the water boils; the pan goes/boils dry; steam; it will turn into condensation; water vapour. [6] 4. (a) Award ONE mark for correctly completing all four rows of the table: 1 Solid soil vitamin tablet plastic beads salt Beaker B D A C (b) Award ONE mark for a response indicating the solid dissolved: 1 salt/it dissolved; it formed a solution. John Buchan Middle School 5

6 ONE mark may be awarded for a response stating that the vitamin tablet dissolved if the pupil has identified that the vitamin tablet is in beaker C in part a). response that does not explain what happened to the solid: it disappeared. it mixed with the water. (c) Award ONE mark for: 1 Beaker D. ONE mark may be awarded for: vitamin tablet. (d) Award ONE mark for: 1 (e) Award ONE mark for an indication that Safara should evaporate the water: 1 evaporate the water; by evaporation. ONE mark may be awarded for a response explaining the beaker should be moved to a warmer place and/or left to dry: move the beaker on to a (sunny/warm) window sill; put the beaker on a radiator; by heating it. John Buchan Middle School 6

7 response where it is ambiguous what is evaporating: evaporate the mixture; evaporate it [it refers to the salt]. filter the solution. [5] 5. (a) Award ONE mark for both correct: 1 The change is non-reversible. The bubbles evaporate. False... True... (b) Award ONE mark for all three materials correctly classified: 1 Material inside the bubble vinegar chalk rock Solid, liquid or gas? gas liquid solid (c) Award ONE mark for: 1 limestone; pumice. Allow: chalk. [3] John Buchan Middle School 7

8 6. (a) Award ONE mark for: 1 dissolving dissolves. Give credit for a correct response that goes beyond the key stage 2 programme of study: a solution it is a solute. it sinks to the bottom mixing [given]. (b) Award ONE mark for classifying all three statements correctly: 1 A gas is produced by the yeast. True A reversible change has happened. False The balloon is flexible. True (c) Award TWO marks for a general comparison describing the relationship between the 2 temperature of the water and the time taken for the balloon to stand up: the higher the temperature, the less time it takes for the balloon to rise the lower the temperature, the longer it takes for the balloon to stand up. or If you are unable to award two marks, award ONE mark for two specific comparisons describing the relationship: a high temperature took a short time and a low temperature took a long time for the balloon to stand. Award ONE mark for a single comparison of the variables: a hot temperature made the balloon stand up in a short time the balloon took a long time to stand up when the temperature was low. Marks may be awarded for responses giving the relationship between the temperature of the water and the effect on the time taken for the balloon to stand up: the warmer the water, the quicker the balloon rises the hotter the water, the quicker gas was produced. John Buchan Middle School 8

9 Do not give credit for a response that includes incorrect science suggesting that the yeast rises: the hotter the water the quicker the yeast rises. Do not give credit for a response that includes incorrect science, changing one or both variables: the hotter the water, the smaller the balloon the hotter the water, the shorter time the balloon stays up for. Award ONE mark for a single comparison of the variables: a hot temperature made the balloon stand up in a short time the balloon took a long time to stand up when the temperature was low response that does not interpret the results: at 3 C it took 52 minutes, and at 50 C it took 4 minutes. (d) Award ONE mark for: 1 no AND a response explaining that the mixtures at 20ºC and 30ºC did not cause the balloon to stand up most quickly: the balloon blew up more quickly at 50ºC the balloon blew up faster at a higher temperature than 20ºC or 30ºC it took longer for gas to be produced at 20ºC and 30ºC than at 50ºC. Award ONE mark for: no AND a response indicating that the yeast works quickest at 50ºC or at a higher temperature than 20ºC or 30ºC: it works quickest at 50ºC at 30ºC it took 16 minutes but it only took 4 minutes at 50ºC. John Buchan Middle School 9

10 ONE mark may be awarded if neither box is ticked but a creditworthy explanation indicates that the pupil believes the information from the cook book is not supported by the results of the investigation. Do not give credit if the yes box is ticked. response that gives a continuous variable relationship between the time to stand up and the temperature of the water: the hotter the water, the quicker it takes to stand [does not give examples from the results]. response that only restates the results in the table: I know this because it was 4 mins at 50 C, 18 mins at 20 C and 16 mins at 30 C. it is easier at higher temperatures [it is ambiguous as to what easier refers to] it is best at 50 C [best must be defined]. Additional guidance [5] 7. (a) Award ONE mark for an indication that the liquid is melted wax from the candle: 1 melted/liquid wax; (candle) wax. Allow: melted candle. Do not give credit for: melted wick; candle. John Buchan Middle School 10

11 (b) Award ONE mark for identifying the process: melt(ing). 1 Do not give credit for: turns to liquid; liquefies [this is what happens when gas is compressed]; liquidised/liquidate; warming, thaws. (c) Award ONE mark for a description of the mass decreasing: the mass decreased/got smaller/ went down/got lower/got less/ went small. 1 Allow: it got lighter; it dropped; there's a loss of weight. Do not give credit for: it got shorter. (d) Award ONE mark for an awareness that the products of burning cannot be changed back: it's a chemical change; you can't get the wax back; it changed to a different material. Allow: you can't re-use a candle after it has burned. 1 Do not give credit for: wax disappears; the wax turned to a gas; burning is irreversible [given]; the wax would have melted [this is a physical change]; the wax has been changed; it's like baking a cake [not specific]. [4] John Buchan Middle School 11