Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Chapter 1 answers Activity 3 a) For example: As water transpires/evaporates from the leaves, the coloured water is transported up the celery stalk through the xylem into the leaves. This turns the leaves a different colour. b) For example: It shows the xylem vessels, which have been stained by the coloured water. c) For example: It shows the coloured water in the xylem. Activity 4 For example: If the leaves are taken off the celery in the red water, there will be no transpiration/evaporation from the leaves and less water drawn up the celery. Accept comments referring to volume, such as: The volume of red water left in the container will be greater at the end of the experiment than the volume of blue water. Activity 5 For example: Activity 7 For example: 1 The amount of water in the body needs to be kept stable. 2 We take in water in food and drink. 3 We lose water through sweating, breathing and urinating. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 1 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 4 The kidneys filter waste from the blood. 5 The kidneys are part of the renal system. Activity 8 a) kidney b) ureter c) bladder d) urethra Activity 9 The correct definition for each term is as follows: nephron A filter that removes urine ureter A tube from each kidney that carries urine to the bladder renal vein Carries cleaned blood back to the heart renal artery Carries blood from your heart to your kidneys Activity 10 For example: Model Part of the renal system A Kidneys B C How it is represented in the model Plastic bottles with filter paper Bladder Filter funnel Ureters Clear tubing Body/heart Plastic bottle Kidneys Purple shapes Renal artery and vein Ureters Bladder Body/heart/liver Blue and red shapes Plastic tubing Yellow shape Plastic box Renal arteries Tubing into kidneys at top Kidneys Sponges Ureters Tubing from each kidney at bottom Bladder Green box Urethra Tap at bottom Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 2 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 11 For example: Model A B C Positive Shows the three main parts of the system (kidneys, ureters and bladder) Shows more detail and uses different colours to represent different parts Detailed and it uses sponges to suggest how blood can be filtered through the kidneys Minus Less detail than the other models Interesting The way filter paper has been used to show a filtering system Could have shown the renal artery going into each kidney and renal vein coming from each kidney back to heart Could have shown the renal artery going into each kidney and renal vein coming from each kidney back to heart Colours make the different parts of the model stand out and it is 3D Use of tap at the bottom of the urinary system suggests being able to control going to the toilet to urinate Activity 12 For example: C is the best model because it shows renal arteries going into each kidney and the sponges have holes in, which models filtering inside the kidneys. A ureter is shown going from each kidney to the bladder, and the tap at the end of the system models the idea that humans can control when they urinate. It does not have labels, so you have to use your knowledge to work out which part is which. Revision test answers 1 nephron 2 B 3 true; false; true; false; true 4 a) Xylem – cells that form long tubes that transport water and nutrients from the roots up the stem to the leaves b) Nephron – a tiny tube that helps filter the blood in the kidneys c) Urea – a toxic waste substance filtered out of the blood by the kidneys 5 For example: Renal arteries carry unfiltered blood from the heart to the kidneys, while the renal veins take filtered blood back to the heart. 6 For example: Both flowering plants and human kidneys are included because both have systems that transport water. In plants, the water is transported from the root hairs through the xylem to the rest of the plant. In humans, the kidneys filter the blood and get rid of excess water. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 3 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 7 a), b) 8 a) b) c) d) renal artery kidney ureter bladder Chapter 2 answers Activity 1 The order of the scientists in the timeline should be: A Joannes Baptista van Helmont (1580–1644) B Stephen Hales (1677–1761) C Jan Ingenhousz (1730–1799) D Joseph Priestley (1733–1804) E Antoine Lavoisier (1743–1794) Activity 2 The ideas developed by each scientist are as follows: Joseph Priestley A gas produced by plants allows things to burn in it. Antoine Lavoisier The gas produced by plants is named oxygen. Jan Ingenhousz Plants take up carbon dioxide. Stephen Hales Air helps plants to survive. Joannes Baptista van Helmont Water is a basic requirement for life. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 4 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 3 a) Van Helmont investigated how watering a willow tree affected its mass. His results suggested that plants only needed water for growth. This was incorrect, but it did lead to other scientists checking his idea. b) Hales discovered that plants needed a ‘portion of air’ to survive, adding to scientists’ understanding of what plants need to live and grow. c) Jan Ingenhousz showed that green plants take up carbon dioxide from the air when they are put in the light. d) They would have discussed Priestley’s experiment, where he put a mint plant in a jar of carbon dioxide and let sunlight shine on it. Priestly shared his discovery that the gas appeared to change to one that allowed things to burn in it. It was Lavoisier who named the gas oxygen. e) Plants take in carbon dioxide and give out oxygen when they photosynthesise. Animals, including humans, need oxygen to survive. Without plants, humans and other animals would not be able to live. Activity 4 a) a) boiling ethanol; b) hot water; c) leaf; d) Bunsen burner turned off b) Ethanol dissolves the chlorophyll and removes the green colour from the leaf. c) chlorophyll d) blue/black e) glucose f) Within the chloroplasts is chlorophyll, which traps light energy to convert carbon dioxide and water into glucose and oxygen. Activity 5 For example: 1 Describe what the starch test is testing. 2 Use scientific language: starch; iodine solution; blue/black; result; leaves; ethanol; boiling. 3 Describe safety procedures/risk assessment. 4 State the result and what it shows. Activity 6 a) To ensure that any starch present at the end of the experiment was produced during the experiment. b) For example: type of plant; size of plant; number of leaves; plastic bag over each plant; plants left in the same place; plants left for the same length of time; plants watered the same amount. c) To ensure that both plants were exposed to light so photosynthesis could take place. d) Learners will need to check if starch is present. e) A leaf from the plant with soda lime/without carbon dioxide will not contain any starch. A leaf from the plant with sodium hydrogencarbonate/enriched with carbon dioxide will contain starch. Carbon dioxide is needed for photosynthesis/starch production. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 5 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 8 a) They were trying to prove that light is needed for photosynthesis. b) Photosynthesis is taking place in Plant A because it is exposed to light, which is needed for photosynthesis. Plant B is in the dark, so photosynthesis cannot take place. c) Place a glowing splint inside the tube of gas collected and see if it re‐ignites. d) water + carbon dioxide ⎯⎯⎯⎯⎯⎯ carbohydrate + oxygen Activity 9 a) Examples of strengths: Part of the question is used in the answer. They know photosynthesis can take place over 24 hours. They state that more glucose will be produced. They link glucose to energy and making cellulose. b) Examples of weaknesses: It does not give the photosynthesis equation. It does not link to solving problems, e.g. need for more food, reducing food miles, being able to produce crops all year and in urban spaces. c) Example of a re‐written answer: Farmers grow some crops – such as tomatoes, cucumbers and sweet peas – indoors, using special lights that are kept on 24 hours a day. This means that plants can photosynthesise day and night, so they can produce more glucose for energy and to make cellulose and starch. This means that crops can grow more quickly and keep growing in the winter months when there is less sunlight. This is important because the population has grown, so more food is needed, and it reduces food miles as it means that crops can be grown in urban areas not just farmland. Activity 10 Learner A’s answer: 1 mark For example: The answer only includes ‘plants need carbon dioxide’ (1 mark). Learner B’s answer: 3 marks For example: Uses first part of the question (1 mark), states that plants need CO2 (1 mark) for photosynthesis (1 mark). Learner C’s answer: 5 marks For example: Uses part of the question (1 mark), states that plants need CO2 (1 mark) and its role in photosynthesis (1 mark). Includes the equation for photosynthesis (1 mark) and explains that food production will be increased (1 mark). Activity 11 Suggested question could be: Explain why some growers place CO2 pipes near the leaves of plants. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 6 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 12 Leaves need chlorophyll to photosynthesise. If a plant has variegated leaves, it is only the green parts with chlorophyll that can photosynthesise. The areas that are not green have no chlorophyll and do not photosynthesise. Activity 13 Plant A Starch would be present in the whole leaf because the whole of each leaf is green, contains chlorophyll and can photosynthesise. Plant B Starch would not be present in the whole leaf because only the green parts contain chlorophyll and can photosynthesise. The parts that are not green would not contain starch because they do not contain chlorophyll, so cannot photosynthesise. Revision test answers 1 B 2 D 3 carbon dioxide + water ⎯⎯⎯⎯⎯⎯ carbohydrate + oxygen 4 Carbon dioxide and water react using energy from sunlight to produce carbohydrate and oxygen. 5 Examples could include the amount of light, carbon dioxide concentration, temperature, etc. Accept amount of water. 6 1 Heat leaf in boiling water for 30 seconds to kill leaf and stop photosynthesis. 2 Boil ethanol in a water bath and add the leaf to the ethanol for a few minutes to remove the green colour (so it is easier to see the colour change). 3 Wash the leaf with water to soften it, then spread it on a white tile (so it is easier to see the colour change). 4 Add iodine solution to the leaf using a pipette. Result: The parts of the leaf that contain starch turn the iodine from brown to blue/black. 7 If non‐green areas turn green, more of the leaf now contains chlorophyll, so more of the leaf can photosynthesise. This means more glucose for growth can be produced by photosynthesis. 8 a) A graph to show the amount of carbon dioxide absorbed by a plant over 24 hours b) Photosynthesis is at its peak at 12 noon. This is when the most carbon dioxide is absorbed, because the Sun is at its highest so the most light energy is available. c) The position of the sun changes and so the amount of light energy for photosynthesis decreases through the afternoon. Photosynthesis slows down, so less carbon dioxide is absorbed. d) approximately 9 g/h e) Oxygen is produced. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 7 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Chapter 3 answers Activity 2 a) Graph A shows continuous data. A line graph is used because there is a continuous range of values. b) Graph B shows discontinuous data. A bar graph is used because there are (four) discrete conditions. Activity 3 Variation skin colour height foot length hair colour blood group ear piercing Genetic Environmental Continuous data Discontinuous data Activity 5 nucleus; chromosome; DNA strand; gene Activity 6 a) Male, because the two sex chromosomes look different so are XY. b) Two chromosomes of the same size should be drawn in the space. Activity 8 Text Image A 2 B 5 C 6 D 1 E 3 F 4 Activity 9 Top row: Bb (brown eye) and Bb (brown eye) Bottom row: bb (blue eye) and bb (blue eye) Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 8 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 10 The pictures of the beaks should show a gradual change from a short, stubby beak to a long, thin, pointed beak. Activity 11 For example: Tortoises usually have domed shells like Tortoise A, but Tortoise B lives on an island with shrubs and low trees. This means that its main food is leaves from the shrubs and trees. Some tortoises might have had a shell that was slightly higher at the front, meaning they could reach higher for leaves to eat. This gave them an advantage, as they could find more food. They passed this trait to their offspring and they in turn passed it on via their genes. The front part of the shell therefore changed/evolved to allow the head and neck to reach for leaves on trees and shrubs more easily. Activity 12 Answer A: 2 marks – mentioned genes for long beaks and offspring inheriting. Answer B: 6 marks – mentioned variation (1 mark), birds with beaks suited to environment (1 mark), had offspring that inherited genes (1 mark), adaptation over time (1 mark), adaptations are genetically inherited (1 mark), birds that did not adapt became extinct (1 mark). Activity 13 Aristotle – 5 Mendel – 2 Darwin – 4 Rosalind Franklin – 1 Crick and Watson – 3 Revision test answers 1 A 2 B 3 For example: Continuous data is where measurements have been taken, e.g. in grams or centimetres. Discontinuous data is usually counting whole numbers of things that have discrete values or groups, such as eye colour, shoe size or people with scars. 4 Genetic variation: blood group; eye colour Both: hair colour; height; skin colour Environmental variation: tattoos; scars; ear piercing 5 23 pairs/46 chromosomes 6 DNA 7 XX 8 XY 9 For example, any two from: Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 9 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test • Different traits can be passed on to offspring. • Inherited factors can be predicted. • Each factor has two sets of instructions, one from each parent. • There are dominant characteristics. • There are recessive characteristics. 10 B B b Bb Bb b Bb Bb 11 For example: Darwin observed that organisms show variation and have different traits depending on the environment they live in. Traits can be passed on through the genes to organisms’ offspring, and this is known as genetic inheritance. Gradually, over thousands of years, new species result from evolution. Species that are not well adapted gradually die out and become extinct. Chapter 4 answers Activity 1 a) placenta b) umbilical cord c) fetus d) uterus Activity 2 The umbilical cord is sometimes called the lifeline because it carries blood back and forwards from the mother to the fetus. It carries nutrients and oxygen from the mother’s placenta to the fetus and then carries waste material back in the opposite direction. Activity 3 Answer 1: 1 mark For example: Mentioned harming the baby, so 1 mark, but did not explain how this can happen. Answer 2: 2 marks For example: Includes that harmful chemicals from smoke and drink pass through the umbilical cord to the fetus. Answer 3: 4 marks For example: States what affects the fetus (1 mark), describes how these things can go through the mother’s bloodstream (1 mark), placenta and umbilical cord (1 mark) to the fetus (1 mark). Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 10 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 5 For example: There is a difference between the infant mortality rates in Afghanistan and Monaco because: • Afghanistan has suffered war. It is a poor country, so hospitals have less equipment and mothers may not get enough food to stay healthy. Many live in poverty and are at risk of catching diseases, and there is a shortage of health workers. • Monaco is a small country. It is wealthy, so poverty is low and hospitals are well equipped. Activity 6 For example: Cigarettes contain over 4000 different chemicals, and many are toxic (poisonous). If you keep smoking during pregnancy, the chemicals can be passed through the placenta and then the umbilical cord to your baby. This may harm your baby: they could be stillborn, premature, have a low birth weight or have birth defects. Activity 7 Prescribed and recreational drugs pass into the pregnant woman’s bloodstream. Some substances pass through the placenta to the umbilical cord and into the blood of the fetus. The liver of the fetus is not able to process the drugs and the baby could be born premature, underweight or stillborn. Activity 8 a) lungs b) spinal cord and brain c) liver Activity 9 For example: • Video – could be eye catching and interesting. • Face to face – allows mothers to ask questions that are relevant to themselves. • Directing to helpful websites – give a range of information and mothers can access them in private. • Text messages or social media apps (e.g. Facebook, Twitter) – lots of pregnant women communicate using their mobile phones, so they could get information quickly to lots of women and keep them up to date. • Leaflets given when women find out that they are pregnant – they can keep the leaflets and look at them often. Leaflets could provide information about other organisations to contact. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 11 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 10 Technology Purpose air filter For example: Cleans air to get rid of harmful particles oxygen saturation monitor For example: Checks oxygen levels in the blood temperature sensor For example: Senses if neonate’s temperature is too low ventilator For example: Helps neonate to breathe portholes For example: Allow people to touch neonate without passing on germs vital signs monitor For example: Checks neonate’s heart is beating properly Activity 11 ‘Neo’ means new and ‘natal’ means relating to birth, so neonate means newborn. Revision test answers 1 A 2 C 3 false; false; true 4 a) For example: A newborn baby b) For example: Tube taking blood with nutrients and oxygen from the mother’s placenta to the fetus and taking waste away c) For example: A baby born before 37 weeks of pregnancy 5 For example, any four of the following: low birth weight, pneumonia, brain damage, blindness, deafness, hepatitis, meningitis, stillbirth 6 For example: Chemicals from cigarettes get into the pregnant woman’s bloodstream. They pass through the placenta to the umbilical cord and so the chemicals get into the blood of the fetus. 7 For example: A neonate might be placed in an incubator because they were premature (born before 37 weeks), underweight or have an illness/disease. 8 Any three of the following: Air filter: Cleans air of particles that might harm the neonate Oxygen saturation monitor: Monitors oxygen level in neonate’s blood Temperature sensor: Monitors neonate’s temperature Ventilator: Helps neonate breathe/gives oxygen Portholes: Allow parents / healthcare workers to touch neonate without passing on germs Vital signs monitor: Monitors heart Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 12 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Chapter 5 answers Activity 4 Example answers in the double bubble diagram: • Similarities in the centre hexagons: for example, recorded notes, used a camera, observed over time, observed animals, collected data, noted observations. • Differences in left‐hand bubbles for learners: for example, studied plants / did not study chimpanzees; worked around their school; observed over weeks, not years; did not work with other people. • Differences in right‐hand bubbles for Jane Goodall: for example, studied chimpanzees / did not study plants etc.; worked in Tanzania; observed the same chimpanzees over decades; worked with local people. Activity 5 a) Multiplied by 100 b) Plant or animal and their food (if animal) Number in 1 m2 quadrat Estimated number in 100 m2 area grass clumps 18 1800 worms (eat dead plant material) 2 200 rove beetles (eat beetle larvae, aphids and small caterpillars) 7 700 dandelions 6 600 ants (attracted to sweet and sugary foods) 100 1000 caterpillars (eat leaves) 1 100 Activity 6 a) For example: They may have found more ants in the quadrat at 3 p.m. because the learners ate their lunches outside, so they might have left sweet/sugary crumbs that attracted the ants. b) Either observation over time, because the students are collecting data from observations across the school day, and/or pattern seeking, because the students are collecting data to find a pattern across the day. c) Limitations could include: only using one quadrat, which might have been placed on an area which was not typical of the whole field; only collecting data on one specific day and at one time. Suggested improvements could include: Survey more than one part of the school field (e.g. using 10 quadrats in different parts of the field); repeat the data collection at different times of day and on different days for a week or month. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 13 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 7 There were few starlings (5) or sparrows (3) at 9 a.m. At 1 p.m. the numbers increased to around five times as many birds for both species. At 3 p.m. there were around three times as many birds of both species compared to 9 a.m. The increases are probably because the students eat lunch outdoors at 12 noon, and may snack as they leave school at 3 p.m. Therefore, there would be crumbs (bread scraps) for the birds to eat at 1 p.m. and 3 p.m. and the birds would be attracted to eat these leftovers. Activity 8 a) For example: leaves → caterpillar → common bulbul → black kite b) For example: If the rove beetles and ants disappeared, there would be fewer insects for birds such as the common bulbul and starling. These birds would have to find alternative sources of food. c) Advice for ensuring the evidence is reliable could include: keeping data on a school computer so it can be added to regularly; getting the whole school involved so that more students collect observations, which will make the database larger; collecting the data and storing it from one year to another to allow comparisons; making a note of any events/changes (e.g. droughts, floods, extreme temperatures, lunchtimes moved inside, changes in school timings), to see if they have an effect on the data. Activity 10 Box 1 Ordovician, 445–430 million years ago, ice age / glaciers / volcanic activity, 85% extinct Box 2 Late Devonian, 376–360 million years ago, sea level rise/fall / less O2 and CO2, 75% extinct Box 3 Permian/Triassic, 252 million years ago, volcano / asteroid / dust, 95% marine invertebrates and 70% land invertebrates extinct Box 4 Jurassic–Jurassic, 201 million years ago, climate change / volcanoes / asteroid, 76% extinct Box 5 Cretaceous–Tertiary, 66 million years ago, asteroid, 75% species extinct Activity 11 Some scientists believe Earth is heading for another mass extinction event because of, for example: global warming, sea levels rising, pollution, human activity leading to climate change, etc. Activity 12 a) Pinta giant tortoise – extinct because they were hunted for food. West African black rhinoceros – extinct due to poachers killing them for their horns (which were sold on the black market and used in traditional medicine). Golden toad – extinct due to human activity, such as deforestation and climate change caused by people burning fossil fuels. Paradise parrot – extinct due to drought, people burning local grass each year and grazing cattle on the grass, all of which severely reduced the parrots’ food supply because they ate the grass seed. Guam flying fox – extinct because humans introduced new predators such as the brown tree snake in their habitat, hunted the flying foxes, and destroyed their habitat through deforestation. Hawai’i ‘o’o – extinct because humans destroyed their habitat and introduced rats, which ate the birds’ eggs. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 14 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test b) The common cause is human activity, such as poaching, hunting, causing climate change, introducing new predators to their habitats, and changing habitats through farming and deforestation. Revision test answers 1 C 2 A and C 3 true; false; true; true; true 4 For example: a) The Great Dying was a mass extinction event where over 75% of plants and animals on Earth became extinct. b) The Red List is the International Union for Conservation of Nature’s (IUCN) list of animals and plants threatened with extinction. c) An extinction event is when animals and plants become extinct in large numbers very quickly. 5 For example: Most of the animals on Earth became extinct / There was a major event, e.g. an asteroid hit the Earth, global temperature change, volcanic eruption. 6 For example: Taking and recording observations over long periods of time is important because it enables scientists to see trends and patterns in data and gives more reliable data. 7 For example: As the number of hares increases or decreases, the number of lynxes follows the same pattern, suggesting the hare is the prey of the lynx. 8 For example: In 1855, the numbers of both lynxes and hares were fairly high. This suggests that the lynx population was healthy because the hare population was high and provided food. Then, the hare population started to fall, perhaps because there were so many lynx to eat them. By around 1862, levels of both were very low, showing the link between predator numbers and lack of prey – when the hare numbers are low, the lynx food source is scarce and so lynx numbers decrease. 9 In most years, as the hare population rises and falls, the lynx population does the same. The two populations directly affect each other, since the lynxes prey on the hares. 10 Any three from: hunting for food; pollution; hunting to destroy a species or for sport; changes in land use such as deforestation for agriculture; climate change; etc. 11 Reasons why scientists disagree could include: the events were millions of years ago; no one was there to witness what happened so we can only use the evidence left behind; the evidence can be interpreted in different ways. 12 The Anthropocene Epoch is the period of time that we live in now. Animal and plant species could go extinct due to the effect of humans on the environments, plants and animals on Earth – for example, due to use of fossil fuels, pollution, deforestation, agriculture and industry causing climate change through a dramatic rise in carbon dioxide in the air, etc. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 15 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Chapter 6 answers Activity 3 a) hydrogen, H, 1, gas, non‐metal carbon, C, 6, solid, non‐metal iron, Fe, 26, solid, metal gold, Au, 79, solid, metal mercury, Hg, 80, liquid, metal b) Similarity: For example, both are made up of neutrons, protons and electrons. Difference: For example, a carbon atom has more neutrons (six), protons (six) and electrons (six) than a helium atom (two of each). Activity 4 Timeline order, boxes from left to right: B, E, C, D, F, A Activity 6 a) The melting points of the elements decrease as you go down the group. b) The boiling points of the elements increase as you go down the group. c) Mono means single or one, so monatomic means that these gases are made up of single atoms, rather than molecules in which more than one atom is joined together. d) Ductile means it can be drawn out into a wire without breaking. This is useful for making jewellery, cables and wires. Malleable means it can be hammered or rolled into thin sheets. This is useful for making foils, jewellery and kitchen utensils. e) For example: Alkali metals Name Uses Noble gases Name Uses lithium medication and batteries helium filling balloons, helping people breathe in hospitals (mixed with oxygen) sodium seasoning food (sodium chloride – salt), cleaning products neon lights, fog lights, lasers caesium solar cells, atomic clocks radon in radioactive research Revision test answers 1 C 2 B 3 C 4 false; true; false; true 5 Any three from: electrical conductors, malleable, ductile, react easily with water Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 16 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 6 Any three from: non‐flammable, tasteless, odourless, colourless, inert/non‐reactive, poor conductors of electricity 7 A monoatomic gas means each gas particle has only one atom. 8 Answer A: 2 marks because it has described the properties of malleable and ductile materials but does not give examples of either or say whether a material can have both properties. Answer B: 5 marks because it has described the properties of malleable and ductile materials, given examples of malleable and ductile materials, and stated that some materials can be both malleable and ductile. 9 The mistakes are: 1 It says periods are vertical rows but they are actually horizontal rows. 2 It says groups are horizontal rows but they are actually vertical columns. 3 It says noble gases are on the left of the periodic table but they are actually on the right‐hand side. 4 It says alkali metals are on the right but they are on the left‐hand side of the periodic table. 5 It says elements are impure substances but they are pure substances. Chapter 7 answers Activity 2 Moyo’s model is incorrect. She has labelled protons in orbits and has neutrons as a cloud around the nucleus. (She has also missed out electrons.) Activity 3 oxygen – unstable neon – stable beryllium – unstable Activity 4 Oxygen has a double bond, so a second strand of spaghetti needs to be added between the two marshmallows. This represents a second covalent bond (a second pair of shared electrons). Activity 5 a) Molecule name Structure of molecule hydrogen oxygen methane H–H O=O H (Note the double bond) | water chlorine Cl–Cl H–C–H | H Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 17 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test b) Learners are likely to agree, because this model does not show the number of bonds between the atoms. Activity 6 oxygen – negative ion, anion neon – no change, ‘not an ion’ magnesium – positive ion, cation Activity 7 A – yes; B – yes; C – no Activity 8 Giant covalent structure Definition – large molecular structure of atoms held together by strong covalent bonds Characteristics/features/facts – high melting and boiling points due to strong covalent bonds Example – diamond, which has a regular tetrahedral shape Non‐example – magnesium oxide Giant ionic structure Definition – large structure of ions held together by forces between opposite electrical charges Characteristics/features/facts – insulators when solid, conductors when dissolved or molten, high melting and boiling points due to strong attraction between ions in the structure Example – sodium chloride, which has a regular cubic shape Non‐example – graphite Activity 9 Simple molecules Giant covalent structures Giant ionic structures A E B C D F Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 18 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Revision test answers 1 2 false; true; false 3 false; true; true 4 false; true; false 5 C 6 C 7 red – oxygen; white – hydrogen; blue – nitrogen; green – fluorine/chlorine; black – carbon 8 Simple molecules have strong forces between the atoms in the molecule, which hold the molecule together. However, they only have weak forces between the molecules. These forces only hold the molecules together when it is cold and are easily broken at higher temperatures (by the increased kinetic energy of hotter moving particles). Giant covalent molecules have strong covalent bonds between all the atoms within the single large molecule. These bonds are require a lot of energy to break, so the substances have very high melting and boiling points. 9 In the solid salt, the positive sodium ions and the negative chloride ions are arranged in a giant ionic structure or lattice. The ions are charged but are attracted to one another and so cannot move around, so solid sodium chloride cannot conduct electricity. 10 a) magnesium: positive; chlorine: negative b) Magnesium loses two electrons; Chlorine gains one electron. c) MgCl2 (For every one magnesium atom, there are two chlorine atoms.) Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 19 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Chapter 8 answers Activity 3 Block Density small medium large density = density = density = = = = . . = 20 kg/m3 . = 20 kg/m3 = 20 kg/m3 Theo is correct. The density is the same for each block because it is the same material (and density is a property of the material, which is not affected by the size of the block). Activity 4 Substance Density ice steel air density = density = density = = = = = 917 kg/m3 = 8000 kg/m3 . = 1.27 kg/m3 Activity 5 1 a) 50 kg = 50 000 g b) 370 kg = 370 000 g c) 419 kg = 419 000 g 2 a) 50 000 g = 50 kg b) 2500 g = 2.5 kg c) 100 g = 0.1 kg 3 a) 5 cm = 0.05 m b) 350 mm = 0.35 m c) 1000 cm = 10 m d) 20 m = 2000 cm Activity 6 Wax – The units should be g/cm3 (or the number should be 950 if in kg/m3). Aluminium – The answer would be correct if in kg/cm3. More common units would be kg/m3 (density = 2700 kg/m3) or g/cm3 (density = 2.7 g/cm3). Stone – The answer would be correct if in g/mm3. More common units would be g/cm3 (density = 3 g/cm3) or kg/m3 (density = 3000 kg/m3). Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 20 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 7 We started by getting (measuring) the mass (not weight) of the block using a top‐pan balance. We found the volume of the block by measuring the depth, width and length using a ruler (three measurements, not two). We calculated the volume of the block by multiplying the depth, width and length together (three measurements multiplied together, not two). Activity 8 Volume of liquid at start Volume of liquid + object Volume of object 50 cm3 60 cm3 10 cm3 20 cm3 47 cm3 27 cm3 72.5 cm3 85 cm3 12.5 cm3 Activity 9 Vinegar is the more dense liquid. The oil is floating on top of the vinegar, so it must be less dense. Activity 10 They have forgotten to subtract the mass of the empty container and have included this in their calculation of the density. Their calculations and method are otherwise correct, so if they find the mass of the empty container (evacuated using a vacuum), they will be able to find the mass of just the gas. They also did not check the volume of the flask (they relied on the volume printed on the flask). The actual volume of gas might be different (although this would have a much smaller effect on the accuracy of the results). Activity 11 Correct order: A, D, C, E, B, F. Revision test answers 1 C 2 B 3 A 4 C 5 volume = 8 cm × 9 cm × 2.2 cm = 158.4 cm3 density = 6 = = 1.073 g/cm3 (or 1073 kg/m3) . volume of stone = 90 cm3 – 40 cm3 = 50 cm3 density of stone = = = = 1.6 g/cm3 Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 21 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 7 mass of honey = 235 g – 33 g = 202 g density = 8 = = 1.40 g/cm3 Measure the mass of the empty container (emptied by using a vacuum). Subtract the mass of the empty container from the mass of the container and gas. Check the volume of the flask by filling it with liquid and measuring the volume of the liquid. 9 The density of the steel bolt is > 1430 kg/m3, as it is more dense than sugar syrup. Any answer greater than 1430 kg/m3 is acceptable. The density of the sultana is > 1000 kg/m3 but < 1430 kg/m3, as it is more dense than water but less dense than sugar syrup. Any answer between 1000 kg/m3 and 1430 kg/m3 is acceptable. The density of the tomato is > 920 kg/m3 but < 1000 kg/m3, as it is more dense than oil but less dense than water. Any answer between 920 kg/m3 and 1000 kg/m3 is acceptable. Chapter 9 answers Activity 1 The more reactive metals in each pair are: a) calcium b) iron c) magnesium d) magnesium e) aluminium Activity 4 magnesium + copper chloride: yes – bubbles released, temperature changes, colours change iron + zinc nitrate: no – no changes observed zinc + lead nitrate: yes – change of colour of metal Activity 5 a) Bubbles of hydrogen gas are formed (slowly) and/or indicator phenolphthalein changes colour to indicate the presence of the alkali magnesium hydroxide. b) magnesium + water → magnesium hydroxide + hydrogen (in either order) Activity 7 a) Iron – Yes, iron is higher in the reactivity series than hydrogen. b) Copper – No, copper is lower in the reactivity series than hydrogen. c) Magnesium – Yes, magnesium is higher in the reactivity series than hydrogen. d) Zinc – Yes, zinc is higher in the reactivity series than hydrogen. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 22 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 8 Any one of the following: iron + hydrochloric acid → iron chloride + hydrogen magnesium + hydrochloric acid → magnesium chloride + hydrogen zinc + hydrochloric acid → zinc chloride + hydrogen Activity 9 a) aluminium + iron oxide → aluminium oxide + iron b) Replacing aluminium with lead would not allow the thermit reaction to take place, because lead is lower in the reactivity series than iron, so it is less reactive than iron. Displacement reactions only take place when a more reactive metal is able to replace a less reactive metal. Activity 10 a) 1 Iron key – yes: iron + copper sulfate → iron sulfate + copper 2 Silver spoon – no reaction 3 Gold ring – no reaction 4 Zinc name badge – yes: zinc + copper sulfate → zinc sulfate + copper b) No, it is incorrect. Only metals that are reactive enough will displace the copper. The others will not change no matter how long they are left in the solution of copper sulfate. c) If the metal that the object is made from is more reactive than copper, displacement will take place and copper will form. If the metal that the object is made from is less reactive than copper, there will be no displacement reaction and no coating will form. Revision test answers 1 no; yes; yes; yes 2 true; false; false; false 3 B and D 4 B and D 5 a) calcium + zinc sulfate → calcium sulfate + zinc b) lead + iron chloride → no reaction c) zinc + hydrochloric acid → zinc chloride + hydrogen d) copper + nitric acid → no reaction 6 Method: Place (equal amounts of) an acid (e.g. sulfuric, hydrochloric or nitric acid) into different test tubes. Place (equal sized) pieces of each of the metals (that can be safely handled, i.e. below calcium) from the reactivity series, one into each tube, including tin. Use a stopwatch to measure a fixed amount of time, e.g. 5 minutes. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 23 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Either count the bubbles from the reaction of each metal with the acid in the time, or collect the gas using a bung to seal the tube, a delivery tube into a water bath and an upturned measuring cylinder with water that will be displaced as the gas fills the test tube. Observation – look for formation of bubbles of (hydrogen) gas or a colour change. Decide if more or less reactive – look at the number of bubbles/amount of gas formed in a particular time (more bubbles = faster reaction) across each of the metals. When comparing the metals, the ones with the most bubbles/amount of gas in a given time will be the most reactive. Chapter 10 answers Activity 2 Metals Acids Salts zinc sulfuric (acid) magnesium chloride calcium nitric (acid) iron sulfate copper hydrochloric (acid) lead nitrate Activity 3 a) chloride b) sulfate c) nitrate Activity 4 Metal Acid Salt magnesium nitric acid magnesium nitrate calcium hydrochloric acid calcium chloride zinc sulfuric acid zinc sulfate Activity 6 Aga’s is the best statement. Ahmed’s statement is not true – it is a type of purification, because the substance is a mixture at the start and separate compounds at the end. Emilia’s statement is not true either, as the bubbles in this case are a sign of the water boiling (turning from liquid to gas), which is a reversible physical change rather than a chemical reaction. Activity 7 The correct order is: B, C, E, D, A. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 24 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 8 a) zinc + sulfuric acid → zinc sulfate + hydrogen b) The correct order is: B, E, C, D, A. c) The two mistakes are: Statement C mentions magnesium but it should be zinc as they are making a zinc salt. Statement B mentions nitric acid but it should be sulfuric acid as they are making a sulfate. Activity 9 magnesium carbonate + hydrochloric acid → magnesium chloride + water + carbon dioxide Question Daanesh’s response Is he correct? Correct answer (if needed) What is the name of the acid used? nitric acid no hydrochloric acid What would be left in the filter funnel? excess unreacted magnesium carbonate yes How would you separate the magnesium chloride from the solution? filtration no Use evaporation to remove the water from the solution, leaving crystals of magnesium chloride. A gas is produced. What do you think it is and how would you test for it? hydrogen gas, tested no for by collecting, inserting a lit splint and getting a ‘squeaky pop’ carbon dioxide, tested for by seeing if it makes limewater turn cloudy Activity 10 Separating copper powder from zinc sulfate solution Filtration Obtaining solid iron chloride from an incomplete reaction of copper chloride and iron (filings) Filtration, evaporation and crystallisation Separating soluble magnesium chloride from a solution Evaporation and crystallisation Revision test answers 1 true; false; true; true 2 true; true; false; false 3 B Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 25 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 4 A 5 a) magnesium + nitric acid → magnesium nitrate + hydrogen b) lead + sulfuric acid → lead sulfate + hydrogen c) calcium carbonate + nitric acid → calcium nitrate + water + carbon dioxide d) magnesium carbonate + hydrochloric acid → magnesium chloride + water + carbon dioxide 6 a) copper carbonate + nitric acid b) Method: Add (excess) copper carbonate to a flask. Add nitric acid. Wait until bubbles have stopped. Filter out excess copper carbonate (using filter funnel and beaker). Heat to evaporate the water from copper nitrate solution until almost dry. Leave to crystallise (pat dry the crystals). c) copper carbonate + nitric acid → copper nitrate + water + carbon dioxide d) 1 2 Replace copper carbonate with calcium carbonate. Replace nitric acid with hydrochloric acid. Chapter 11 answers Activity 2 Fastest B (typically takes seconds), D (typically takes a few minutes), A (typically takes many minutes, up to an hour), C (typically takes weeks, months or years) Slowest Activity 3 a) copper + oxygen → copper oxide b) 2.5 g (The total mass of products must equal the total mass of reactants: 12.5 g.) c) 5 g: double the mass of copper will require double the mass of oxygen d) 25 g: double the mass of copper oxide is also produced (or 20 g + 5 g = 25 g) Activity 4 a) Non‐closed system as air can get in b) magnesium + oxygen → magnesium oxide c) Bella is correct. Activity 5 Suki – the total amount of energy afterwards equals the total amount beforehand. Emma’s answer shows more energy afterwards so breaks the conservation of energy law. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 26 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 6 a) acid + metal carbonate → metal salt + water + carbon dioxide (any order) b) 157.5 g – 155.8 g = 1.7 g c) non‐closed d) Production of bubbles of (carbon dioxide) gas e) hydrochloric acid + calcium carbonate → calcium chloride + water + carbon dioxide f) HCl + CaCO3 → CaCl2 + H2O + CO2 (unbalanced) 2HCl + CaCO3 → CaCl2 + H2O + CO2 (balanced) Activity 7 a) acid + metal → metal salt + hydrogen b) closed c) Bubbles of (hydrogen) gas released at the site of the reaction d) magnesium + hydrochloric acid → magnesium chloride + hydrogen e) Mg + HCl → MgCl2 + H2 (unbalanced) Mg + 2HCl → MgCl2 + H2 (balanced) Activity 8 a) carbon dioxide b) Activity 9 The large combined surface area of the custard powder dust would make a combustion reaction happen very quickly indeed and so could produce a dangerous explosion. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 27 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 10 a) Particle size Mass of container at start of experiment/g Mass of container at end of experiment/g Mass lost during experiment/g small 185.5 181.4 4.1 medium 185.5 182.7 2.8 large 185.5 183.9 1.6 b) The larger the particle size, the lower the amount of mass lost (or the smaller the particle size, the greater the amount of mass lost). c) The larger the particle size, the lower the rate of reaction (or the smaller the particle size, the higher the rate of reaction). Activity 11 Temperature of acid (°C) Time taken to fill the container (s) 20 123 30 89 40 63 50 45 60 32 Activity 12 a) Catalysts can be installed in cars in catalytic converters. These speed up the rate at which harmful gases like carbon monoxide are converted into less toxic substances like carbon dioxide and water, reducing pollution. b) Enzymes and metals like platinum, rhodium and iron Activity 13 a) oxygen b) heat c) oxygen d) heat e) fuel Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 28 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 14 Revision test answers 1 false; true; true; true 2 B 3 D 4 a) CH4 + O2 → CO2 + H2O (or balanced: CH4 + 2O2 → CO2 + 2H2O) b) HCl + CaCO3 → CaCl2 + H2O + CO2 (or balanced: 2HCl + CaCO3 → CaCl2 + H2O + CO2) c) HCl + Mg → MgCl2 + H2 (or balanced: 2HCl + Mg → MgCl2 + H2) 5 6 Reactant 1 Reactant 2 Product 1 Product 2 36.5 g of hydrochloric acid 12 g of magnesium 46.5 g of magnesium chloride 2 g of hydrogen 9.8 g of sulfuric acid 10 g of calcium carbonate 13.6 g of calcium sulfate 1.8 g of water Product 3 (if applicable) 4.4 g of carbon dioxide a) zinc + sulfuric acid → zinc sulfate + hydrogen b) Measure the mass of the reaction vessel before the experiment (using a balance). Measure the loss of mass from the reaction in a certain time. Use this to calculate the rate of reaction. 7 a) magnesium carbonate + nitric acid → magnesium nitrate + water + carbon dioxide b) Collect the gas in a gas syringe. Measure the amount of gas produced in a certain time. Use this to calculate the rate of reaction. 8 As the concentration of sulfuric acid increases, the rate of reaction also increases. Increased concentration means an increased number of acid particles in the solution. This increases the chances of collisions (and reactions) with magnesium particles. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 29 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 9 The larger the pieces of calcium carbonate, the smaller the total surface area. This reduces the rate of reaction. Reactions take place at the surface of the pieces: the smaller the surface area, the fewer reactant particles can come into contact to react. 10 The higher the temperature, the faster the particles (of acid) are moving. This increases the rate of reaction. The faster‐moving particles are more likely to collide (with the sodium thiosulfate particles). They are also likely to hit the particles harder, increasing the chances of a reaction. Chapter 12 Answers Activity 2 a) water: 13 102 + 13 006 + 13 207 = 39 315 vegetable oil: 5551 + 5335 + 5422 = 16 308 soil (wet): 8131 + 8059 + 8032 = 24 222 sand: 2919 + 3022 + 2858 = 8799 39 315 3 = 13 105 16308 3 = 5436 24 222 3 = 8074 8799 3 = 2933 b) water c) sand d) water e) sand f) Higher, because more energy would have to be transferred to the substances Activity 3 a) no – move around more b) yes c) yes d) no – it measures the average energy of the particles (the temperature). Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 30 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 4 Example of energy transfer Energy store at start – amount and type of store Energy store at end (1) – amount and type of store Energy store at end (2) – amount and type of store Chemical store in the battery Transferred as light, ending up in a thermal store when light is absorbed Transferred to surroundings, ending up in a thermal store Thermal store in the kettle Transferred to surroundings, ending up in a thermal store Switching on a torch A kettle cooling down to room temperature An exothermic chemical reaction (e.g. lighting a match) Chemical store in the match Transferred to surroundings, ending up in a thermal store Transferred as light to surroundings, ending up in a thermal store Activity 5 Inside the liquid: Convection Warmer particles are more spread out and so less dense. The warmer particles rise and carry energy upwards. From the top surface of the liquid: Evaporation Particles move away from the surface of the liquid, taking thermal energy with them. Through the bottom of the cup: Conduction Particles vibrate due to their kinetic energy and pass these vibrations on to the particles next to them. (Note: A china cup is an insulator, so this will not happen very quickly.) From the side surface of the cup: Radiation Infrared radiation (waves) is emitted from the side of the cup, passing the energy to the surroundings. Activity 8 Answer A: full marks (5 marks); all points scored. Answer B: 1 mark scored for identifying water is not a good conductor; no other points scored. Answer C: 2 marks; scored for identifying radiation and stating that energy moves from a warm object to the surroundings. Incorrect description of radiation as particles rather than waves prevents further points being scored. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 31 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Revision test answers 1 C 2 D 3 Thermal energy is the total amount of kinetic (movement) energy of all of the particles in an object. Temperature is the average amount of kinetic (movement) energy of the particles in a substance. Compared with a glowing metal light filament, a bath of warm water has the larger amount of thermal energy. Compared with a bath of warm water, a glowing metal light filament has the higher temperature. 4 Conduction happens through solid substances, particularly metals. Convection explains why warm air rises. Radiation can be detected through infrared imaging. Evaporation occurs when particles leave a surface and take the thermal energy with them, cooling the surface down. 5 Possible examples include: seeing warm objects at night finding people/objects hidden by smoke in a fire diagnosing disorders in the body without touching them. The warmer parts of the objects give out more infrared radiation than the cooler parts. 6 Evaporation – particles of water in the sweat are heated by the warm skin. They then have enough energy to leave the surface (evaporate). They take the energy that they are carrying with them, away from the skin and into the surroundings. This cools the skin down. 7 Energy cannot be created or destroyed. It simply transfers from one place/object to another. Answer can include any example that shows that the amount of energy within an isolated system does not change. For example, with a pan being heated, the total amount of energy supplied to the pan ends up heating the pan, its contents and the surroundings. 8 Metals have electrons that are free to move (sometimes described as a ‘sea’ of electrons). When a metal is heated, the electrons in that part move about more quickly and pass on thermal energy to nearby electrons and atoms, so the heat spreads quickly through to the cool part of the metal. 9 A thermal insulator is a poor conductor of thermal energy. Most substances that are not metals are insulators, such as wood, plastics, fabrics, etc. Chapter 13 answers Activity 2 The correct order is: (A), E, B, C, D, (F). Activity 3 Cho’s statement is correct. Sounds are quieter when you are further away from the source of the sound (as the sound spreads out). Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 32 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 4 a) vibrating object b), c) compression / high pressure (these labels can be either way around) d), e) rarefaction / low pressure (these labels can be either way around) f) direction of travel of sound Activity 5 Medium Gas, such as air Solid, such as glass A vacuum, such as outer space Liquid, such as seawater Speed of sound 330 m/s 2840 m/s no sound 1560 m/s Activity 6 a) louder sound b) quieter sound c) higher pitched sound Activity 7 As the police car approaches, the pitch is higher than normal. As the police car is nearest them, the sound is a normal pitch. As the police car is travels away, the pitch is lower than normal. Activity 8 Loud sound A large stone Quiet sound A small stone A high frequency A few stones, thrown in quickly one after the other A low frequency A few stones, thrown in slowly one after the other Activity 9 The noise can be cancelled out if the opposite waves are played at the same time as the sound. If that happens, you will get destructive interference. Revision test answers 1 true; false; true; false; true 2 C 3 A Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 33 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 4 5 compressions high pressure rarefactions low pressure high amplitude loud sound low frequency low pitch A amplitude B wavelength C amplitude D wavelength 6 Key points you might include are: 7 vibrations caused by moving object hit particles within the air causing compressions and rarefactions travel as sound waves (to the ear) a) For example: Waveform A has a lower amplitude than waveform B, so A is quieter than B (or B is louder than A). The waveforms have the same wavelength (same frequency) so they will have the same pitch. b) For example: Waveform A has a lower frequency (or a longer wavelength) than B, so A is lower pitched than B (or B is higher pitched than A). The waveforms have the same amplitude, so have the same loudness. 8 For example: The source of the sound is moving (compared to the listener). This changes the pitch of the sound. As the object approaches, the pitch is higher than it would normally be. As the object moves away, the pitch is lower than normal. (The faster the source is moving, the larger the change in pitch.) 9 For example: To model a sound wave, the motion should be back and forth (not side to side). Changing how often they move their hand will change the frequency (not amplitude). Changing how far they move their hand will change the amplitude (not frequency). Chapter 14 answers Activity 3 Circuit A: The lamp will not produce any light, as the only lamp in the circuit is broken. Circuit B: Neither lamp will light, as one of the lamps is broken so the series circuit is incomplete. Circuit C: The bottom lamp will light, as the loop it is in forms a complete circuit. The broken lamp in the first loop will not light. Activity 4 a) A and C are correct Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 34 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test b) Ammeter Current/amps A1 1.0 A2 0.5 A3 0.5 A4 1.0 c) No matter where you place the ammeter in a loop, the current reading is the same. This is because the current is the same at all points in a loop. Activity 5 B and C are correct. Activity 6 a) The middle cell is in the opposite direction to the other cells. b) There are two cells in one direction, and one in the other. This means that the battery produces a smaller voltage, equivalent to one cell (rather than three). c) 1.5 V d) Cells in one direction = 3.0 V; cells in the other direction = 1.5 V; 3.0 V − 1.5 V = 1.5 V Activity 7 For example: Current is the rate of flow of charge (or how much charge flows in a given time) around a continuous circuit (or loop). Voltage is the ‘push’ given by the cell or battery and is the energy ‘carried’ by each unit of charge. Activity 8 a) The brightness of the lamps does not change. b) If one of the lamps breaks, the other lamps will stay lit. Activity 9 a) Yes, it is correct. b) No, they have connected the ammeter and voltmeter in the wrong places so the readings are not correct. Activity 10 Circuit A: fixed Circuit B: variable Circuit C: variable Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 35 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Revision test answers 1 A 2 A 3 B 4 false; true; false; false; true 5 6 lamp Glows when current passes through ammeter Used to measure the current in a circuit current The flow of charges around an electric circuit voltmeter Always placed in parallel with a component ampere The unit of electric current a) b) The lamp will light and the buzzer will sound. c) i) 2.8 V ii) 2.8 V d) i) stays the same ii) decreases iii) decreases e) The voltage (push) of the battery does not change, but no electricity flows around the circuit as the switch is open. This means there is no voltage across the other components. 7 a) lower b) series c) parallel d) the same e) divided Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 36 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 8 a) The circuit in the top loop is incomplete, as lamp A is in series with lamp B. No current can flow around this loop, so no electrical energy is transferred to lamps A and B and they do not light up. Lamp C stays lit, as it is in parallel with lamp B and its circuit remains complete. A current can flow and electrical energy can be transferred to lamp C. b) Ammeter Current/A A1 0.75 A2 0.5 c) The current is halved as the resistance is twice as much. Chapter 15 answers Activity 2 a) 1D; 2F; 3A; 4B; 5C; 6E b) 1, 2, 4 – Jigsaw appearance of coasts and distribution of some fossils and rocks indicates that all of the land mass was together at one time. c) 3, 5, 6 – Mountains continue to form and grow, earthquakes and volcanoes occur along plate edges, polarity of magnetic stripes changes and magnetic stripes are moving apart over time. Activity 4 a) 1 – mantle; 2 – inner core; 3 – crust; 4 – outer core Activity 5 a) both b) S waves c) both d) S waves e) both f) S waves g) both h) P waves i) P waves j) P waves Activity 6 a) (best) B; A; C (worst) b) Answer B has correct science and lots of detail to explain the ideas. Answer A has correct science but fewer details. Answer C has incorrect science. Revision test answers 1 Maps of the Earth’s landmass; mapping of rock distribution; mapping of earthquakes; mapping of volcanoes 2 A and B 3 false; false; true; false; false Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 37 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test 4 5 P waves Seismic waves that can travel through solids and the liquid outer core S waves Seismic waves that cannot travel through the liquid outer core Seismic waves The two types of waves produced in an earthquake that travel down into the Earth Seismometer Measuring instrument used to analyse seismic waves produced in an earthquake Example answers: a) Magma – liquid/molten rock below the Earth’s surface b) Tectonic plate – massive, irregularly-shaped slab of solid rock floating on top of magma c) Seismic wave – a wave that shifts energy in the Earth produced by an earthquake (or other means) 6 a) P wave b) S wave c) d) both P wave e) both 7 false; true; false; false; false 8 left‐hand image = P waves; right‐hand image = S waves 9 10 Any five of the following points: The hottest part of the Earth’s structure is the inner core. The inner core heats up the outer core, which in turn heats up the mantle. The mantle is made up of magma (molten rock), so the energy is transferred through it by convection. Convection occurs when thermal energy is transferred through a liquid or a gas by the movement of particles in the substance. The magma closest to the outer core heats up first. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 38 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test The particles in this magma move more quickly / gain more kinetic energy, and spread apart, becoming less dense than the magma above. This less dense magma then rises and cooler magma replaces it. The convection currents rise to underneath the Earth’s crust and move along under the tectonic plates. This moves the plates. Chapter 16 answers Activity 3 a) feeding b) decomposition c) respiration Activity 4 This is the complete correct text: Carbon dioxide is classified as a ‘greenhouse gas’ because it allows heat energy from the Sun to travel through and reach the surface of Earth, but then prevents much of the heat energy radiating from the Earth’s surface from passing back out into space, because the carbon dioxide absorbs the energy and warms up the atmosphere, like a greenhouse. This process is known as global warming. Over two hundred years ago, the Industrial Revolution occurred in several countries and factories were built, which used coal, oil and gas to power machines using a combustion reaction. This released more carbon dioxide into the atmosphere. Scientists have measured global temperatures since 1880 and the patterns show that the temperature is rising. As well as monitoring temperatures, scientists have measured changes over time in precipitation, humidity, wind speed and atmospheric pressure. These changes are known as climate change and are linked to rises in carbon dioxide levels. Activity 5 a) 1940s b) 800 000 years c) Zero d) About 410 parts per million; this is the current level e) Just below 1 °C, in 2016 and 2017 f) Since the 1970s/1980s; from this point, the gradient of the graph shows a steep increase g) Since the 1950s; the graph is very steep and increasing rapidly over a very short time period h) For example: Yes, because both are now going up very quickly. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 39 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Activity 6 Example answers: a) Rising sea levels: flooding of low‐lying islands and coastal areas; people moving away from these areas Changing humidity levels: more water in atmosphere; changing weather patterns; very heavy rain; flash floods; droughts; destruction of property / habitats / crops / livestock Extreme weather events: larger and more frequent extreme weather events, such as hurricanes, tornadoes and heavy snowstorms; leading to floods, damage to environments and property and increased risk to life b) End reliance on fossil fuels; find and use alternative fuels; invest in clean and renewable energy sources; use sustainable transport; keep homes well insulated; encourage people to reduce the amount of meat they eat or even switch to vegan diets; plant trees; protect forests and oceans; reduce consumption of goods; use less plastic Revision test answers 1 photosynthesis; respiration; feeding 2 photosynthesis 3 true; false; false; true; true; false 4 greenhouse gas Any gas in the atmosphere that absorbs some thermal energy from the Sun, with the result that the atmosphere becomes warmer carbon dioxide A colourless, odourless gas consisting of a carbon atom covalently double‐bonded to two oxygen atoms global warming Increase in average temperature of the Earth, which is likely to lead to significant climate changes climate change Long‐term shifts in temperatures and weather patterns 5 Rapid increases in global temperature; rapid increases in level of carbon dioxide 6 For example: increasing sea levels; increasing humidity; more frequent extreme weather events 7 a) both b) respiration c) combustion d) both e) combustion f) both g) respiration 8 For example: As the Earth heats up, ice (e.g. at the poles, in glaciers and on mountains) is melting, causing sea levels to rise. This leads to flooding of low‐lying areas. Some islands have been or will be lost, and people will have to move away from coastal areas to live, etc. 9 For example: keep fossil fuels in the ground; find alternative fuels; invest in clean and renewable energy sources; use sustainable transport and move items over shorter distances to reduce the use of fuel; keep homes warm by using insulation as much as possible; encourage people to eat less meat or even switch to vegan diets; plant more trees, which generate oxygen from carbon dioxide; protect forests and oceans, which capture carbon and reduce the amount of carbon dioxide in the atmosphere; reduce consumption of goods, so fewer items need to be manufactured, using less energy, etc. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 40 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Chapter 17 answers Activity 2 a) Width and depth of craters b) The height from which the rock is dropped c) Same rock; same person dropping rock; same method of release to drop rock; same measuring instruments used; same person using the measuring instruments; sand smoothed over before each drop d) The likely width of the crater is 16 mm, because the values tend to go up by 2 mm for every 10 cm increase in drop height. The likely depth of the crater is 7 or 8 mm, because the values tend to go up by 1 mm for every 10 cm increase in drop height. e) As the height from which the rock is dropped increases, and therefore the speed at which the rock hits the sand increases, the depth and width of the crater created also increases. f) They could have repeated each drop and calculated average values. Activity 3 a) For example: craters; climate change; mass extinctions b) Dust and ash are sent into the atmosphere and can block the Sun’s heat and light. c) Dust, ash, water vapour and droplets are sent into the atmosphere and can block the Sun’s heat and light. d) When large numbers of species become extinct at the same time. Activity 4 a) Evidence from rocks: 3, 6 b) Evidence from movement: 1, 4 c) Evidence from observations: 2, 5 Activity 5 Example answer: Stellar nebula: A stellar nebula can form from clouds of hydrogen gas in the universe. Gravity pulls the hydrogen atoms together into a huge ball, called a protostar. Protostar: Gravity continues to squash the gas atoms in the protostar closer and closer together. This increases the pressure and the temperature inside the ball. Eventually, the pressure on the hydrogen atoms is so great that they fuse together to make helium gas. This releases energy as heat and light, and the ball begins to glow. Main sequence star: As the pressure and temperature continue to increase inside the glowing ball, more hydrogen is converted into helium. The ball starts to shine and a main sequence star is ‘born’. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 41 Cambridge Checkpoint Science Revision Guide Second Edition for the Cambridge Secondary 1 Test Revision test answers 1 between Mars and Jupiter; in the same orbit as Jupiter 2 A and B 3 false; false; true; false; true; false 4 5 Moon The Earth’s only natural satellite satellite A moon, planet or machine that orbits a planet or star debris disc A ring of rocky material orbiting a star or planet Big Splash A collision theory hypothesising how the Moon formed a) Impact winter – A long period of cold weather due to the impact of a large asteroid or comet on the Earth's surface. b) Mass extinctions – Events where large numbers of species become extinct in a short time. 6 Evidence from rocks; evidence from the movement of the Earth and Moon; evidence from observations in the universe 7 a) both b) asteroid c) moon d) moon e) asteroid f) both 8 The correct order is: B, C, A 9 Example answer – each point is worth 1 mark: A stellar nebula can form from clouds of hydrogen gas in the universe. Gravity pulls the atoms of hydrogen gas together into a huge ball. This ball is called a protostar. The force of gravity continues to act on the gas atoms and squashes them closer and closer together. This increases the pressure and temperature inside the ball. Eventually, the pressure on the hydrogen atoms becomes so great that they fuse together to make helium gas, releasing energy as heat and light. The ball begins to glow. As the pressure continues to increase and more hydrogen is converted into helium, the ball starts to shine. A main sequence star is ‘born’. Cambridge Checkpoint Science Revision Guide for the Cambridge Secondary 1 Test © Rosemary Feasey, Andrea Mapplebeck and David Bailey 2023 42