Nes og fe OF Wye:}c a0 eles o q | Se ean i Coheed Mary Jones, Diane Fellowes-Freeman and David Sang Cambridge Checkpoint Science WorkbookMary Jones, Diane Fellowes-Freeman and David Sang Cambridge Checkpoint Science Workbook 8 o CAMBRIDGE UNIVERSITY PRESSCAMBRIDGE UNIVERSITY PRESS University Printing House, Cambridge CB2 8BS, United Kingdom ‘One Liberty Plaza, 20th Floor, New York, NY 10006, USA 477 Willanstown Road, Port Melbourne, VIC 3207, Australia 314-321, 3rd Floor, Pot 3, Splendor Forum, Jsola District Centre, New Delhi ~ 110025, India 79. Anson Road, #06-04/06, Singapore 079906 Cambridge University Press is part of the University of Cambridge. It furthers the University’s mission by disseminating knowledge in the pursuit of ‘education, learning and research at the highest international levels of excellence. wwwecambridge.org Information on this tide: www.cambridge.org/9781 107679610 © Cambridge University Press 2012 ‘This publication isin copyright. Subject to statutory exception and to the provisions of releva wgagrvements, 1no reproduction of any part may take place without the written permission of Cambridge University Press First published 2012 40 99 88 37 36 35 34 38 92 31 90 29 Printed in Great Britain by CPL Group (UK) Led, A catlague mcd fortis publication i aia fom te British Library collective eens ISBN 978-1107-67961-0 Paperback ‘Cambridge University Press has no esponsibility fr the persistence or accuracy ‘of URLs for external or third-party internet websites refered to in tis publication, and does not guarantee that any content on such websites is, o will remain, accurate or appropriate. Information regarding prices, travel timetables, and other factual information given in this work is correct at the time of frst printing but ‘Cambridge University Press does not guarantee the accuracy of such informnation thereafterWhat this workbook for? ‘This workbook will help you to develop your knowledge and skill in science. As you work carefully through it, you should find that you get gradually better and better at doing things such as: + using your knowledge to work out the answers to questions, rather than just remembering the answers + organising, displaying and using data from secondary sources + planning experiments, recording results, drawing graphs and making. conclusions. How is the workbook organised? The workbook exercises are arranged in the same order as the topics in your coursebook. Each exercise has the same number as a topic in the coursebook. ‘There is not always an exercise for each topic, For example, there is an exercise for cach of topics 1.1, 1.2, 1.3 and 1.4. There is no specific exercise for topic 1. “The exercises will help you to develop the skills you need to do well in science. ‘The exercises are not quite the same as the questions that you will meet in the Progression Tests or your Checkpoint examination. This is because the exercises are to help you to get better at doing particular things, rather than testing how well you can do them. a (°Introduction: Biology Unita — Plants Ll ‘The beginning of photosynthesis 1.2 Drawing leaves 1.3 The effect of different colours of light on the rate of photosynthesis 1.4 Plants in space ~ Extension Unit2 Food and digestion 21 Fibre in food 22 Energy requirements 23 Digestion 24 Functions of the digestive system 26 How do teeth help in digestion? Unit3 The circulatory system 1 Blood flow in the human circulatory system 33 Hummingbirds 3.3, Adapting to high altitude ~ Extension Unit4 — Respiration 4 A model of the human respiratory system 42 Lung surface area and body mass 43 An investigation using hydrogencarbonate indicator 44 Recording breathing rate and depth 45 Smoking statistics Units Reproduction and development 5 External fertilisation 5.3 ‘The menstrual cycle 54 Gestation periods. 5.5 Human growth 5.6 Does caffeine affect birthweight? Chemistry Unit6 States of Matter 6.1 Particle theory 6.2 Diffusion 6: Investigating diffusion 65 Gas pressure Unit7 Elements and compounds 7.1 Atoms a The Periodic Table Contents 10. 13 15 7 19 21 22 SBERS SE8 & we BS 8874 Compounds 64 7.5 Using formulae 65 Unit Mixtures 81 Mixtures 66 8.2 More about mixtures 67 84 Chromatography 70 85 ntific terms related to solutions a 8.6 Solubility 2 8.7 Solubility investigation 4 Unit 9 Material changes 9.1 Physical and chemical changes 76 9.3 Reactions with acids 7 94 Before and afier the reaction 78 9.5 Explaining unexpected results 80 9.6 Detecting chemical reactions 82 9.7 Why does iron rust? 84 Physics Unit10 Measuring motion 10.1 Allabout movement 10.3. aleulations involving speed 10.4 Patterns of movement 92 10.5 Allina graph 96 Unita Sound LL. Making music 99 11.3. The speed of sound 101 114 Londer and louder Lot 11.5 Range of hearing 106 Unit 32 Light 12.1 Travelling light 108 12.2 Shadows un 12.3. Seeing by reflection 113 12.4 Refraction of light 115 12.6 Coloured light 116 Unit 13 Magnetism 13.1 Magnets and magnetic materials 119 15.2 Magnetic forces, making magnets 121 13.3 Representing magnetic fields 124 13.5 Magnets and electromagnets 127 13.6 Revising magnets and electromagnets 128 Contents «Exercise 1.1 The beginning of photosynthe This exercise will remind you about how we can use rocks to find out what happened long ago. You will also need to think about what is produced by photosynthesis. ‘The chart shows some important events that occurred during the very early history of the Earth, 1500 million years ago ‘The first, very simple animal-like organisms appeared, 3000 million years ago ‘The first organisms that could photosynthesise appeared. mn years Living organisms first appeared on. 4600 million years ago The Earth was first formed. © + 200Unit 4 Plants ® 4 How long alier the formation of Earth did the first life appear? 2. Suggest how we know when the different kinds of organisms first appeared on Earth, on years ago, there was 1lo oxygen in the Earth’s 3. Upto about 3000 mil atmosphere. Today, about one fifth of the atmosphere is oxygen gas. the information on page 6 to suggest what caused this change. 4 Suggest why animal-like organisms did not appear on Earth until after the first organisms that could photosynthesise had appeared. + rons @Exercise 1.3 The effect of different colours of light on the rate of photosynthesis Sunil wanted to find out which colour of light would make a plant photosynthesise fastest. ‘The diagram shows the apparatus that he set up. blue cellophane —_ water test tube —_ pondweed colourless cellophane — — water test tube Sunil shone a light onto each piece of pondweed. He counted the number of bubbles that was given off in one minute. He did this three times for each piece of pondweed, These are his results, red - 10, 12, 1 blue - 8, 12, 10 green - 4,5, 6 colourless ~ 11, 13, 12 )4 Plants @® What was the variable that Sunil changed in his experiment? What was the variable that Sunil measured in his experiment? List three variables that Sunil should have kept the same in his experiment. first variable ........ second variable . third variable ... Draw a results table in the space below, and fill in Sunil’s results so that they are easy to understand. Remember to include a column where you can write in the mean value for each set of results. sre @@® Unit 2 Plants 5 Complete the bar chart to show Sunil’s results. i t HEE ed ween blue colourless colour of tight 6 Write down a conclusion that Sunil can make from his results. © 4 PlantsUnit 1 Plants ® Exercise 1.4 Plants in space - Extension You will need to use both your own knowledge and the information in the box to answer these questions. Some of the questions will make you think back to topics that you learnt about last year ~ gravity and soil Read the information, and then answer the questions that follow. The International Space Station has been orbiting the Earth since the year 2000. More than 200 astronauts, from many different countries, have worked on the Space Station Some of the astronauts carry out experiments to investigate how plants grow in space. The plants are grown in small, enclosed, transparent containers, ‘They are given artificial light. Air and watcr are pumped around their roots. ‘The experiments show that, when there is no gravity at all, the plant roots and shoots grow randomly in all directions, So some of the plants are spun gently in a machine called a centrifuge. This produces a force to which the plants respond just as they would respond to gravity. One experiment has tested how the plants grow in different kinds of soils. If a soil has very large particles, the water in it escapes easily: The water forms litle droplets and floats away into the air. Ifthe particles in the soil are very small, then air does not flow through it casily and the roots don’t get enough oxygen to survive, Phe plants grown in the Space Station include dwarf wheat, strawberries and mizuna. If humans ever travel to Mars, they will need plants to provide them with oxygen and food. ‘The experiments also show that the astronauts enjoy e plants. 4. Suggest why the plants in the Space Station are grown in enclosed containers, 2 Suggest why water has to be pumped directly to the plant roots, rather than just poured into the container from a watering can, ssn ©@® Unit 4 Plants 3 a _ Explain why the roots of a plant grow in all directions if there is no gravity. b Describe how this problem has been solved in the Space Station. 4 Explain why a sandy soil would not be a good choice for growing plants in the Space Station. (Use what you know about soils, and also the information on page 13, o help you write your answer) 5, Describe three reasons why it would be useful for astronauts travelling on a long journey to grow plants in their spaceship. first reason second reason . third reason .. @® 1Exercise 2.1 Fibre in food This exercise asks you to use data in a table, and to look for a particular pattern in the data. You'll also practise drawing a bar chart. ‘The table shows the fibre content of some different foods. apples bananas beans bread, brown bread, white chicken coconut I com eggs fish fies (potato chips) ‘mutton peas plantain potatoes ice spinach sweet potatoes vam alrolafeles/alalelelolefe/Zlefe)ala 1 Explain why we need fibre in our food. 2 Which kinds of food do not contain any fibre? 2 Food and digestion ©@® Unit 2. Food and digestion 3 Calculate the total amount of fibre there would be in a meal containing 200g of chicken, 200g of rice and 100 of spinach. Show your working. 4 Choose any ten of the foods in the table, and draw a bar chart to show how: much fibre they contain, Think about a sensible order in which to arrange the different foods in your bar chart. Remember to label each axis fully.\\ Unit 2. Food and digestion ( Exercise 2.2 _ Energy requirements inthis exercise, you will practise Finding information in a written passage, and ina bar chart. Make sure that you write the answers in your own words ~ don’t just copy sentences from the passage. Read the information, and then answer the questions. The cells in your body are always using energy. All of their energy comes from the nutrients in the food that you eat ~ especially from carbohydrate and fat. Cells can also get energy from protein. If you eat too much of these nutrients, your cells do not use all of the energy from them. Your body turns the extra nutrients into fat. The fat is stored, mostly just below the skin. If you don’t eat enough of these nutrients to provide all the energy your cells need, the cells have to find another source of energy: They break down the body’s fat stores to provide energy. You lose weight. Different people need different amounts of energy each day. In general, men, use more energy than women, People who have active lives use more energy than people who spend a lot of time sitting down 2, Which two nutrients provide most of the energy for the cells in the bod 2 A man eats food containing more energy than he uses up each day. What will happen to his weight? Explain yc answer, 2 fostansczesion (@)3. The bar chart shows the average energy needs of six different groups of people. "| _ a daily energy requirements / Mt) a What are the average daily energy needs of an eight-year-old girl? b Approximately how much energy should an eight-year-old girl take in (as food) each day? © Suggest why most eight-year-old boys need less energy cach day than a teenage boy. Suggest why, on average, an adult woman needs less energy each day than an adult man. @) 2 wean nestExercise 2.3 Tt exercise will help you to t words associated with Digestion jet and digestior Write clues for this crossword, Unit 2. Food and digestion (®) ik about the exact meanings of several of the Across ‘alols cfPofefi A \ r i Imi ofife ufife m t e e a i “a 55 t nfult ifefo}e a|u g a r 8 e r y a s c r t h Pa ifn}o ° o| nfe 2 tow snssension@) 2 soosancigesionUnit 2. Food and digestion (@® Exercise 2.4 Functions of the digestive system There’s a diagram showing the different organs in the digestive system on page 24 in your coursebook. Their functions are described on page 25. This exercise will help you to lear the position of each organ, and to link each function, Decide which organ carries out each of the functions in the list below. Then use a ruler to draw a label line to the organ in the diagram, and label its function, You could write in the name of the organ, too, if you like. You will need to write in some of the functions more than once, because they are carried out by more than one organ. Functions, + makes pancreatic juice + small molecules of nutrients are + produces hydrochloric acid absorbed through the walls + protein is digested here + water is absorbed through the walls + starch is digested here + makes bile + facis digested here + stores b + saliva is produced here + food is chewed into smaller piecesA\ ‘ (GLY Unit 2 Food and digestion Exercise 2.6 How do teeth help in digestion? This exercise gives you practice in planning an investigation. It will also help you to think about how teeth and enzymes each have a part to playin digestion. You may be able to carry out your investigation after your teacher has checked it. IF so, do make improvements to it if you think of any while you are working. We use our teeth to break food up into smaller pieces. This helps enzymes to get at all parts of the food, so they can break the large molecules into small molecules. Plan an investigation to answer this questio Does chewing food help amylase to break down the starch in bread faster? You don't need to actually chew the bread, You can just break it up into smaller pieces. 4, Which variable will you change in your investigation? 2 How will you change this variable? 3. Which variables will you keep the same? 4 How will you measure how quickly the amylase breaks down the starch? QD) 2 rootntcigestinUnit 2 Food and digestion ® 5, How will you record your results? Draw a results table that you could use. 6 Predict the results you would expect, Explain why you would expect this to happen. 2 vossnssean (@)Exercise 3.1 Blood flow in the human circulatory system This exercise will help you to remember how the human circulatory system works. The diagram is not quite the same as the one in the coursebook, so you will have to think about it. Remember to take care when drawing labels ~ use a ruler to draw label lines and make sure the end of the line is in exactly the right place. ‘The diagram on the opposite page shows a plan of the human circulatory system. 1 Draw an arrow inside each of the four blood vessels that connect with the heart, showing which way the blood flows inside them, ide ~ to show how the blood ish. 2. Draw two arrows inside the heart — one on each, flows through it. Your arrows can be curved if you 3 Label each of these parts: Jungs artery carrying blood to the lungs vein carrying blood from the lungs kidneys artery carrying blood to the idneys vein carrying blood from the kidneys 4 Use a red pencil to lightly shade all the parts that contain oxygenated blood. 5, Use a blue pencil to lightly shade all the parts that contain deoxygenated blood.Unit 3 the circulatory system @® 3 trecratsonssten (@(® Unit 3 The circulatory system Exercise 3.2. Hummingbirds Data that you have not collected yourself is said to be a secondary source. In this exercise, you will practise organising, displaying and interpreting data from a secondary source. You will also practise looking for correlations in data Hummingbirds are very small and very active birds. They feed on nectar, which they collect by inserting their beaks into lowers as they hover. Scientists measured the body masses of ten hummingbirds. They also measured the mass of the heart of each hummingbird, These are their results, hummingbird | body mass 2.2g, heart mass 0.053 hummingbird 2. body mass 7.5g, heart mass 0.13, hummingbird 3. body mass 9.8g, heart mass 0.18 g hummingbird 4 body mass 6.2, heart mass 0.14, hummingbird 5 body mass 7.8, heart mass 0.16, ummingbird 6 body mass 3.5, heart mass 0.06 g hummingbird 7 body mass 12.0g, heart mass 0.23 g hummingbird 8 body mass 4.2¢, heart mass 0.10g. hummingbird 9 body mass 9.5, heart mass 0.15 hummingbird 10 body mass 5.8g, heart mass 0.13 g 4 Record these results in a table in the space below. Think about the best order in which to arrange the results, Remember to give clear headings to the columns or rows.Unit 3 the circulatory system @® 2. Draw a line graph to show these results. Put body mass on the x-axis (the one along the bottom), Put heart mass on the y-axis (the one up the side). Draw a best fit ine through your plotted points. PEER 3. The scientists concluded that there is a correlation between the body mass of| a hummingbird and the mass of its heart. (A ‘correlation’ means that there isa relationship between the two masses.) Explain how their results provide ‘evidence for their conclusion 4 Suggest a reason for the relationship between the body mass and heart mass of a hummingbird. 3 The circulatory system ©3 The circulatory system (Q) v Exercise 3.3 | Adapting to high altitude - Extension Do you know the altitude at which you live? This exercise asks you to think hard about how the human body can make changes to allow a person to live even at very high altitudes, where oxygen is in short supply. You will need to link together information given in writing, information given in two graphs, and also your own knowledge. Not easy! ‘There is much less oxygen in the air at high altitudes than there is at low altitudes. When a person moves quickly from a low altitude to a high altitude, they may get out of breath very quickly and feel ill, This is because they cannot get enough oxygen into their blood. However, if they move upwards mnore gradually, their body has time to respond to the change by making more red blood cells. A party of trekkers wanted to walk from Phakding to Everest Base Camp in Nepal. They planned their trek carefully, to give their bodies time to adjust to the changes in altitude, The graph shows their plan. 60000 --——7— ] ToT Tebse dae] { Gorak Shep, an 50000 Be : | e State SpE tebte t % aso0 Dinara Phe | 3 poche H F sooo | i i Et i = tt HH ro000f | } HA Ea t ° 0 100 0 200 20 trekking time/ hours 41 How many days did the trekkers predict it would take them to walk from Phakding to Everest Base Camp? altitude at Namehe? 3 How long did the trekkers plan to stay at Namche?Unit 3 the circulatory system ® 4 Suggest why they planned to stay at Namche and Tengboche for several days, before continuing to climb upwards, and the the blood, One of the trekkers was a doctor. She took blood samples from hers other trekkers during their trek. She measured the amount of oxygen ‘The graph shows the results amount of oxygen in blood HEH f 100 150 200 350 ‘trekking time /hours 5, Explain why the amount of oxygen in the trekkers’ blood decreased during the trek. 6 If a person travels quickly from Phakding to Everest Base Camp, the amount of oxygen in their blood becomes so low that they may become very ill. Explain why this did not happen to the trekkers. 3 tnecialnoystenExercise 4.1 A model of the human respiratory system You may be able to make or use a model like the one described in this exercise. Thinking hard about how it works will help you to understand how breathing movements make air move into and out of the lungs. You will need to use what you know about gas pressure, which is explained on pages 76 to 77 in the coursebook. The diagram shows a simple model of the human respiratory system. _ lass tube belljar — balloon stretchy rubber 4. Suggest which parts of the model represent each of these parts of the body. the lungs the diaphragm ......----s0 the trachea .. the rib cage os. ©) 4 seraUnit 4 Respiration (® 2 a What happens to the space inside the bell jar when the stretchy rubber is pulled downwards? Complete this sentence about gas pressure: ‘The more space a gas has, the its pressure is. € What happens to the pressure of the air inside the bell jar when the stretchy rubber is pulled downwards? 3. When the stretchy rubber is pulled downwards, the balloons inflate. Here is some more information about gases and pressure: + The pressure of the air outside the bell jar does not change when the stretchy rubber is pulled downwards + Gases flow from a high pressure area to low pressure area Use this information, and your answers to 2a, b and ¢, wo explain why the balloons inflate when the stretchy rubber is pulled downwards a resites @Wn ® Unit 4 Respiration Exercise 4.3 An investigation using hydrogencarbonate indicator You have probably used limewater to test for carbon dioxide. In this exercise, you will learn about another way to test for this gas, using an indicator. You will also need to use your skills in planning investigations, thinking about variables, using results to make conclusions and making predictions. Hydrogencarbonate indicator changes colour according to how much carbon dioxide there isin it + The indicator is purple when there is no carbon dioxide. + The indicator is red when there is a low concentration of carbon dioxide, + The indicator is yellow when there is a high concentration of carbon dioxide. Kushi set up four boiling tubes like this goure platform lve — dead ~ live germinating plastic “| maggots seeds seeds beads hhydrogencarbonate Indicator solution a 8 c D> Kushi recorded the colour of the indicator in each tube at the start of her experiment. Then she left the tubes in the laboratory for two hours, and recorded. the colour again, This is what she wrote down. A red yellow B red red C red yellow D red red ® 4 RespirationUnit 4 Respiration ‘® 4 Suggest why Kushi used a gauze platform in each tube. 2. Suggest why Kushi put a bung in cach tube. 3, Describe two variables that Kushi kept the same in her experiment. 4 Construct a results table in the space below, and complete it to show Kushi’s results 4 resistor &)5, Explain Kushi’s results. 6 a Predict the result that Kushi would obtain if she set up another tube containing some little living green plants. b Explain your prediction,Unit 4 Respiration (® 7. Plan an experiment, using the apparatus that Kushi used, to find the answer to this question: Do bean seeds respire faster than pea seeds? Remember to think about the variable you will change, the variables you will keep constant, and the variable you will measure. a renotoe @( @® Unit 4 Respiration Exercise 4.4 Recording breathing rate and depth People who are keen on keeping fit often like to measure their breathing rates when they are exercising. In this exercise, you will work out some values from a slightly different kind of graph than you have used before, Once you have found these values, you will try to explain them. Pietro used a machine to measure his breathing rate. He breathed in and out of the machine. The machine recorded the volume of air he breathed in and out, with each breath, for one minute. Pictzo collected a set of results when he was sitting still, and another set when he was running on the spot Then he printed out the results that the machine recorded. ‘This is what they looked like: atest during exercise k ES fy o.5dim? volume {a=} Lt volume time/s time/sUnit 4 Respiration @® 4 How many breaths did Pietro take in one minute when he was resting? 2 a Use the graph to work out the volumes of air breathed in with each of the first ten breaths that Pietro took when he was resting. Write them down, b Calculate the mean volume of these ten breaths. 4 a Use the graph to work out the volumes of first ten breaths that Pietro took when he was rum b Calculate the mean volume of these ten breaths. 5, Explain the reasons for the differences in Pictro’s breathing when he was resting and when he was running. a reviainExercise 4.5 Smoking statistics In this exericise, you will practise displaying a set of data as a bar chart. First, though, you will try to find some data for yourself, using the internet. You will then need to think about the labels for the axes of your bar chart, the scales that you will use and how to draw the bars. Once you have drawn your bar chart, you will use it to help you to answer some questions. The table shows the percentage of women and men who were smokers in ten countries in 2009, Russian Federation 24 chile 32 Indonesia 3 Netherlands 27 3h China 2 5 Maldives rn 42 Egypt 1 40 Pakistan 6 [ 33 India 3 46. Nigeria 4 10 1 If your country is not listed in the table, use the internet to find the data for it. If your country is isted, find data for another country that you are interested in. Country Percentage of women who smoked Percentage of men who smoked ©) 4 eesvronUnit 4 Respiration ® 2 On the grid below, construct a bar chart to display the data in the table, and the other data that you have found. t t H 3a In which country did the greatest percentage of women smoke in 2009? b _ Inwhich country did the greatest percentage of men smoke in 2009? © Inwhich country was there the biggest difference in the percentage of women who smoked, and the percentage of men who smoked? von ©Exercise 5.1 External fertilisation This exercise involves using new information, and what you have already learnt, to work out the answers to questions. You will also think about how different animals are adapted to reproduce in different ways. Read the information below, and then answer the questions that follow. Tn mammals, including humans, fertilisation happens inside the body. A sperm cell fuses with an egg cell inside the oviduct. This is called internal fertilisation In most amphibians and fish, fertilisation happens outside the body. The female lays her eggs in water. Then the male adds sperm cells to them. The sperm cells swim through the water, find the eggs and fertilise them. Amphibians, such as tree frogs, have to go back to water to breed. Tree frogs often lay their eggs in little pools of water that are trapped in holes in trees, or in bromeliad plants, 4 Explain the meaning of the term fertilisation.Unit 5 Reproduction and development (/(, 2 Explain the difference between internal fertilisation and external fertilisation. 4 Most animals that have external fertilisation produce more eggs than animals that have internal fertilisation. For example, humans produce only one egg cell ata time. Fish produce thousands of eggs at a time. Suggest some reasons for this 5 semaiconataetonenAY ( Unit 5 Reproduction and development Exercise 5.3 | The menstrual cycle This exercise gi graph 4 Draw one line from each word to join it to its definition. Words Definitions ovulation the monthly loss ofthe uterus ining the joining together of the nucleus of menstruation ‘amale gamete and a female gamete the cel that is formed when a male | Settee | gamete fetilises 2 female gamete embryo the release ofan egg from an ovary a ite ball of ells, formed when the aygote zygote divides ‘The graph shows how the lining of the uterus changes during one menstrual cycle. ovulation thickness of wall ° z 4 a 28 time / days @) 5 pcan and devtepmentUnit 5 Reproduction and development @® 2 How many weeks does the menstrual cycle shown in the graph last? 3, The first day of the eycle was on 1st, June. On which date did ovulation happen? 4 On which of these dates could fertilisation happen? Circle the correct answer. Ist June 12th June 15th June 5. Explain why it is important for the lining of the uterus to start to get thicker before ovulation happens. 5 tesmactonanddeopmen (@)AS) (& Unit 5 Reproduction and development Exercise 5.4 Gestation periods In this exercise, you will practise organising data in the best way. You will also think about the meaning of the word ‘correlation’, and practise using data to Support an argument. ‘The gestation period of a mammal is the time between fertilisation and the birth of a baby animal. Itis the time during which the young animal develops, inside the mother’s uterus. The table shows the mean mass of an adult female of eight different species of ‘mammal, and the mean gestation period for that species. moose (elk) 550. 245 llama 3 330 goat 45 150 wolf 40. 64, lion 150 108 [rabbit 1 33 elephant 5000 640) chimpanzee 40 227 In the table belovg rearrange the data so that it is easier to see if there is a relationship between the mean mass of a female and the mean gestation time.AY Unit 5 Reproduction and development (® 2 Is there a correlation between the mean mass of a female and the mean gestation time? Explain your answer, and use figures from the table to support it 3. Suggest why the figures in the table are shown as ‘Mean mass’ and “Mean gestation time’, rather than simply “Mass? and ‘Gestation time’. 5 renoucionaedevtopment (@)5 Reproduction and development (@) v Exercise 5.5 Human growth This exercise gives you practice in reading graphs. You will have to think carefully about how you can work out the rate from a graph. The rate of growth is how quickly size changes over time. So you will need to look at the steepness of the line on the graph to answer the questions about rate. “The graph shows the mean heights of boys and girls of different ages. 200 75 150 boys 125, average height /cm 6 50 35 — o 2 4 6 & 0 2 4 6 age / years 4 What is the mean height of boys at age 12? 2. Between what ages is the mean height of girls greater than the mean height of boys? 3. Between which of the following ages is the rate of growth of boys the greatest? Girele the correct answer. 0-2 years 4-6 years 16-18 years ©) 5 Reproduction and development. A) Unit 5 Reproduction and development (Q ‘4 There is a growth spurt ~ that is, the rate of growth increases ~ at puberty. Use the graph to suggest when puberty happens in girls .. in boys 5 repoducionsndceveopne (@)(2 Unit 5 Reproduction and development Exercise 5.6 Does caffeine affect birthweight? In this exercise, you will look at some data collected by researchers in Sweden. ‘You will practise using data to make conclusions, and thinking about how an investigation could be improved. A study was carried out in Sweden to investigate the idea that women who drink a lot of coffee during pregnancy might have smaller babies. 1037 pregnant women took part. ‘They each answered a questionnaire about how much coffee they drank. When their babies were born, their birthweights were measured. The results are shown in the table. less than 100 3660 100 t0 299 =] 3663 300 to 499) 3597, 500 or more 3694 1 Plot these results as a bar chart on the grid. Think carefully about the range for the scale on the y-axis. Remember that you do not need to begin at 0. r tT E : " 4 +4 4 EEEEEE HHH + { + +Unit 5 Reproduction and development (> 2 What conclusion can you make from these results? Explain your answer, and use figures from the table to support it. 3 Suggest two ways in which the researchers could have improved their study. 5, Reproduction and development ©Exercise 6.1 Particle theory This exercise will help you to understand and remember particle theory. Remember that ‘explaining’ something means that you have to say not only what happens, but also how or why it happens. Explaining is more difficult than describing! 4 In the boxes below, draw diagrams to show how the particles are arranged in a solid, a liquid and a gas. Remember that all the particles should be the same size. Solid Liquid Gas 2. Explain, in terms of particle theory, what happens when ice is heated and melts, to form water. holder fron bar © 6 States of matterUnit 6 States of matter (® Use particle theory to explain why this happens. 4 Use the terms below to match the statements below. Each word may be used once, more than once or not at all boil compressed condensation _—_evaporation freeze gas heat liquid melting move solid vibrate A state of matter where the particles do not touch each other: b When a gas is cooled to form a liquid: aeeETONEN Particles in a solid do this: Solid changing wa liquid: @ When aliquid changes into a gas: F ‘The particles in liquids and gases can do this: & The state of matter that can be compressed: 6 States of matter ©@® Unit 6 states of matter Exercise 6.2 _ Diffusion In this exercise you will use particle theory to explain how diffusion takes place. This exercise will also give you practice in answering questions involving data. 4 When you pass a food stall you can smell what is being cooked. Expl particle theory, how this happens. using When there is an unpleasant smell in a room, what can you do to get rid of i Explain why this works, in terms of particle theory. 3 Marco and Jaden are investigating diffusion. They have 12 Petri dishes filled with agar jelly that has been made up with slightly acidic water and Universal Indicator solution. The jelly is red, Marco and Jaden have cut circles from the centre of the jelly using a cork borer. They have been given four bottles of sodium hydroxide of different concentrations. The bottles are labelled A, B, C and D.Unit 6 States of matter @® he students place a measured volume of the sodium hydroxide from bottle A into the well in the jelly. After 10 minutes they mark and sodium hydroxide has diffused into the ‘They do this for the sodium hydroxide from boitles B, G and D. w far the Phey repeat the test twice more. Here are their results, A 32 29 35, 8 o7 | 06 05 c [45 24 2.6 D 46 1a | What safety precautions should Mareo and Jaden take? b Explain how Marco and Jaden know how far the sodium hydroxide has diffused. € Look at the students’ results table, Circle any result which you think does not fit the pattern, 4 Complete the table by calculating the mean distances diffused in 10 minutes. (Remember to do the right thing about any result that you think does not fit the pattern.) @ Which botile contains the strongest sodium hydroxide? Explain how you know this. 6 states of matter ©(® Unit 6 states of matter Exercise 6.3 Investigating diffusion In this exercise you will use ideas about diffusion and ideas about investigation skill 4 You are making tea for some friends. Serena likes her tea very weak, Jose likes his very strong and you prefer yours somewhere in between. Explain, using particle theory, how you make tea for everyone 2. Imagine that you have four food dyes to test, A, B, and D. Imagine that you are going to investigate which food dye diffuses most quickly @ Which variable will you change? b Which variable will you measure? How will you do this? You diagram if it helps you to explain. © Which variables will you keep the same? ( ) 6 States of matterUnit 6 states of matter @® d_— How many times will you carry out each test? Explain why you will repeat the tests, @ How will you know which dye diffuses the most quickly? f — Draw a results table to show how you would display the results, Fill in the headings of the rows and columns. (Of course, of the table, because you don’t have any results.) you cannot fill in the rest & Why did you choose this way to display the results? 6 States of matter ©@® Unit 6 States of matter Exercise 6.5 Gas pressure This exercise will give you the chance to make sure you understand what causes gas pressure. 4 For each sentence, draw a circle round the set of words that correctly completes it Gas pressure is caused when particles: collide with each other collide with the surfaces around them Gas pressure increases when particles are: squashed into a smaller space allowed to spread out into a larger space Gas pressure increases when a gas made colder made hotter 2 Ashraf is at an airport. He has a packet of rice crackers. The packet contains agas. © 6 States of matterUnit 6 States of matter ® Ashraf takes the packet onto an aeroplane. When the aeroplane is high in the sky, the air pressure inside the cabin gets less. The packet inflates. @ When Ashraf was at the airport, the gas inside the packet was at the same pressure as the air around it. What does this mean? Underline the correct answer, * Gas particles inside the packet collided with the packet more often than gas particles outside the packet. + Gas particles inside the packet collided with the packet less offen than ‘gas particles outside the packet. + Gas particles inside the packet collided with the packet just as often as as particles outside the packet. b What changed when Ashraf was in the aeroplane? Underline the correct answer * Gas particles outside the packet collided with it less often than they did at the airport. + Gas particles outside the packet collided with it more often than they did at the airport. ¢ Use your answers to a and b to explain why the packet inflated when Ashraf’ was in the aeroplane. 6 States of matter ©Exercise 7.1 Atoms This exercise will help you to remember the differences between atoms and motecul 14. Which diagrams show molecules? ? “a 2 What can be said about all the atoms in an element? 3 Atoms and molecules are both particles. Explain the difference between an atom and a molecule. 7 Elements and compoundsUnit 7 Elements and compounds @® 4 Draw atoms or molecules in the boxes, Use a circle to represent an atom 6 individual atoms 4 molecules, cach made of 2 atoms 3 molecules each made of 2 atoms, and 2 molecules each made of 4 atoms 7 senertsancconoaines ®)7 Elements and compounds (® v Exercise 7.3. The Periodic Table This exercise will help you to remember the properties of metals and non- metals and some basic information about the Periodic Table. Questions 3 and ‘4 will help you to practise using symbols. 4. Write truc or false next to each of the following statements. a Allnon-metals are gases. b Metals have high melting points. © Metals conduct electricity d= Non-metals have a dull surface. € — Non-metals are found on the lefi side of the Periodic ‘Table f Inthe Periodic Table, a group runs down the table. 2 Draw circles around the examples below that are non-metals. chlorine silver helium carbon iron mercury calcium neon sodium sulfur gold zine @Q) 7 stomenssan compoundsUnit 7 Elements and compounds (® 3 Choose the symbols from the list and match them with the names of the elements, Be §S K C B Ar O Ne Cl Ca H calcium ‘carbon onygen beryllium hydrogen potassium neon chlorine 4 Some elements have symbols that do not appear to match their names. For ‘example, the symbol for sodium is Na. Why is this? 7 Elements and compounds ©Exercise 7.4 Compounds rent elements. This exercise will help you to name compounds made from 4 What is the name of the compound formed when the following elements are combined together? a iron and chlorine b sodium and oxygen © calcium, carbon and oxygen . hydrogen and fluorine € potassium, nitrogen and oxygen .. ashame ReSTER aT f potassium and nitrogen .. 2. Which elements are found in the following compounds? a magnesiumoxide... b carbondioxide. © copper sulfate .. calcium chlorate ......:ssscceesseteeesseeeeenniee aluminium chloride .........004 f sodium sulfide . @) 7 tienensareconsounsUnit 7 Elements and compounds (@® Exercise 7.5 Using formulae This exercise will help you to practise using a compound's name to work out what it contains. You will also practise using a formula to work out not only what the compound contains, but also what its name is. 1 The formula for potassium hydroxide is KOH. Which elements does it contain? 2. Which two elements do all hydroxides contain? 3. The formula for sulfuric acid is H,SO,, Name the three clements that sulfuric acid contains. 3. b How many atoms of each element are contained in one molecule of sulfuric acid? 4 Complete the table. go sulfur dioxide cone sulfur atom bonded to two oxygen atoms - aluminium chloride ‘one aluminium atom bonded to three chlorine atoms calcium sulfide ‘one calcium atom bonded to one sulfur atom Mgco, 7 cenensaniconoinds (@)Exercise 8.1 Mixtures exercise will give you practice in ident compounds. The diagrams show particle diagrams. Use the diagrams in the boxes below to answer the questions, boo 2? . 1 Which boxes contain gases? 2 Which boxes contain a mixture? 3 Which box contains a liquid? © 8 MixturesExercise 8.2 More about mixtures This exercise will give you practi dat playing and interpreting When people talk about gold, you might have heard them say it is 24 carat or 18 carat. What does ‘carat’ mean? It is a unit to describe how pure the gold 24 carat gold is pure gold. If the carat number is lower than 24, then the gold is mixed with another metal ~ it is an alloy. The other metal is usually silver or copper. Acarat stands for one twenty-fourth. So you can use the unit to work out exactly what proportion of an alloy is gold. 24 carat gold is 24 x 57 = 5 tis twenty-four twenty-fourths gold, so it is pure gold, 1_9 9 carat gold is 9X — = =. It is nine twenty-fourths gold. ‘The remaining fifteen twenty-fourths are other metals. How hard the ‘gold’ is depends on the amount of gold used and the type of metal used to make the alloy An assistant in a jewellery store advises a customer (o buy a gold ring that is less than 24 carat. He tells the customer that a ring with a lower proportion of gold looks almost the same as pure gold, but itis harder. Is this true? The table shows some data on the hardness of ‘gold’ 9 80 - 4 90 18 120 22 40 - 24 _ 30@® Unit 8 mixtures 4. Plot a graph of the information in the table, Take care with the scale on the horizontal axis, 130 x20 no # 100 - 90 aes { 0 70 4 hardness/ t nit aroivaryunts 5 50 30 10 purity carats © 8 MixturesUnit 8 mixtures >) 2 Is the advice that the assistant gave the customer based on science or opinion? Explain your answer. 3, Describe the pattern shown by the graph. 4 You may have expected that the 9 carat gold would be harder than the 14 or 18 carat gold. The data shows that it is not Can you suggest why this isso? (Clue ~ is there another variable, other than the amount of gold in the alloy, that could be affecting the hardness?)Exercise 8.4 | Chromatography is exercise will give you pra: interpreting a chromatogram. A food scientist is testing the food colouring used in cans of drink. She has to check that any colouring used does not contain any banned chem She places drops of the drink on chromatography paper. She allows the colouring to separate using water. She also makes another chromatogram, using drops of all the permitted chemical colourings. If she finds anything that does not match with these colourings, she will have to carry out further tests. The diagrams show her two chromatograms, ° 7 _* e e : . 8 e e ’ “es "8 1, Why is the spot of drink placed above the water line at the start of the process? 2. How many different colourings has the scientist found in the drink? 3. Draw a circle around the dye in the drink that is wot on the permitted list of colourings. 4 Explain why the scientist should carry out further tests on this colouring found in the drink. ® : —Unit 8 mixtures (& Exercise 8.5 Scientific terms related to solutions in using the correct terms involve’ 4. Use the terms given below to label the diagrams. Each term may be used once, more than once or not at all. dissolves evaporates filtrate insoluble mixture saturated solid solute solution solvent temperature volume 8 Mixtures )) @@ Unit 9 material changes Exercise 9.4 Before and after the reaction This exercise will help you to understand and explain what happens to the atoms in a chemical reaction. It also gives you some practice in using the idea of conservation of mass. 4. ‘The products of a chemical reaction contain the elements calcium, chlorine, hydrogen, oxygen and carbon, What el s were present in the reactants? 2 The particle diagram shows the reactants in a chemici reaction, Complete the word equation and draw a particle diagram for the missing product. sulfur = + oxygen > @) 9 worsirnea Unit 9 Material changes 3 This the word equation forthe reaction of magnesium arbonate with hydrochloric acid magnesium: | [ hydrochlork | J —| & Which elements are present in magnesivn urbonate Which elements are present in carbon digsisas | © [ater contains the elements oxygen and hydrogen Where dicl the "drogen in the water come foun inthis reacting 4 Where did the chlorine in the magnesiurs hloride come from in this reaction? 4 If the mass of the produets the reaction above was 45g, what was the mass of the reactants? 5 When m, and hyd esiuim reaets with suliar acid the products are magnesium sulfate Uf there are 15.g of magnesium at the start of magne the m the reaction how much sium sulfate? m will be present 6 Explain what is meant by the term conservation of mass, $Me changes ©Unit 9 material changes Exercise 9.6 Detecting chemical reactions his exercise will help you to identify when a chemical reaction has taken ) place. You will also need to use some chemical knowledge that you leantin | earlier units. 4 Give two ways you can tell that a chemical reaction has taken plac 2. Suresh adds some potassium to a beaker of water: The potassium fizz When the fizzing has stopped, Suresh adds Universal Indicator solution to U aw our will the Universal Indicator be when it is mixed with b Explain why the Universal Indicator will be this colour € Has a chemical reaction taken place? Explain your answer ‘odium hydroxide in a beaker of water. The pH changes 3 Joanie dissolves Has a chemical reaction taken place? Explain your answer® Unit 9 material changes (@ 4 Afua mixes a solution of potassium iodide with a solution of lead nitrate. Both of the solutions are clear and colourless. ‘The resulting mixture is cloudy and yellow. State two clues that suggest a reaction has taken place b The yellow precipitate is lead iodide, one of the products in this reaction, What is the name of the other product? € This second product is not a precipitate. Suggest where this product is.Exercise 9.7 Why does iron rust? In this exercise you will practise using what you know about why iron goes rusty. Rusting is a chemical reaction that is not useful. Surriya is investigating the conditions needed to make iron nails rust. She has set up the experiment as below | — boiled water calcium chloride to absorb water ~ water Acryair —Bwaterandair Cater and no air 1 What is the chemical name for rust? 2 In which tube will the nail go rusty? 3, How do the conditions in tube G prevent air reaching the iron nail? 4, In Surriya’s experiment she notices that the nail in tube A goes a little rusty. a Isthis an expected result? b Suggest how this nail could have rusted, 5, What could Surriya do to stop a piece of iron from rusting? Suggest two ideasUnit 9 Material changes @® 6 Plan an experiment to find out if an iron nail rusts more quickly when itis warm than when it is cold. Remember to think about the variable you will change, the variables you will, keep constant, and the variable you will measure. 9 tata chanes H)Exercise 10.1 Allabout movement ‘These questions will make you think about movement and how we can measure speed. 4. The paragraphs helow describe a boy's journey to school. Omar wasn’t looking forward to school. He walked slowly along the road. ‘Then he heard footsteps behind him. It was his friend Wahid, running to catch up with him, ‘Together, they walked to the corner of the street to wait for the bus. A car hurried past, throwing up clouds of dust. On the wall nearby, a spider was creeping along. A lizard dashed out and caught the spider. (Omar saw an aircraft flying overhead, leaving a white vapour trail. He thought it would be good to fly so high, or even to 200m off to Mars in a speeding spacecrafi. @ Inthe paragraphs above, draw circles around all the words that show that something is moving, b Inthe space below list all the things that are moving, from the fastest to the slowest Fastest: 00. Slowest: @) 2 weassins nonUnit 10 Measuring motion (® 2 Imagine that you are in a car, driving along a main road, Along the road, there are signs telling you how far itis to the next town At the roadside, there may be marker posts every 100 metres, Describe how you could use these roadsigns to work out the average speed of the car 20 nevsuinsnoion (@)> Unit 10 Measuring motion Exercise 10.3. Calculations involving speed This exercise will give you practice Take care calculating speed, distance and time. ith units. Speed may be in m/s or km/h. 1 A bird flies 75m in 15s, Calculate its speed. 2A bus travels from one city to another, a distance of &0km. It takes 1.6 hours, Calculate its average speed on the journey 3 Aspider runs along the top of a wall at a speed of 0.24m/s. How far will trun in 58? @) 2 westernUnit 10 Measuring motion 4 An advertisement for a new car states that its top speed is 180km/h. IF it could travel at this speed for 3h, how far would it go? 5. Ahab has been sent to the shops by his mother. The shops are 1200m from his, home. If Ahab can run at an average speed of 6m/s, how long will it take him to reach the shops? 6 A Japanese bullet train can travel at 300km/h, How long will it take to cover section of track 180km in length? 10 nesuinenoton (@)10 Measuring motion (@® v 7 The table shows the World Records for male sprinters in 2011 over different distances. Complete the table by calculating the average speed of each runner. 100 9.58 200) 19.19 400 43.8 Over which distance do sprinters have the greatest average speed? 8 A robber is in a fast car, hurrying away from the scene of his erime. His car can go at 150km/h. He will be safe if he can reach the border, 40km away. A police car arrives at the scene of the crime. The police are late! The robber has already travelled 10km towards the border. The police car sets off'in hot pursuit a How faris the robber from the border at this time? b Calculate how long it will take the robber to reach the border, @) 10 vesuirgmaonUnit 10 measuring motion ® © How fast must the police car travel if it is to catch the robber before he reaches the border? 10 esxsinenotion (@)® Unit 10 Measuring motion Exercise 10.4 Patterns of movement These questions will help you to understand how an object’s movement can be represented rent ways. 4a A ticker timer can show the pattern of movement of an object. The timer marks a dot on the tape 30 times each second. The tape below was made by pulling it at a steady speed through the timer. The dots on the tape are i i 2 On the blank tape shown below, draw the pattern of dots you would expect to see for an object moving at a faster, steady speed. b The tape below was attached to an object that was speeding up. The dots ‘on the tape get farther apart as the object goes faster. start ‘On the blank tape shown below, draw the pattern of dots you would expect to sce for an object that was slowing down. (Mark the ‘start’ point on the tape.)Unit 10 Measuring motion @® € On the blank tape shown below, draw the pattern of dots you would expect to see for an object that speeds up and then moves at a steady speed. (Mark the ‘start’ point on the tape.) 2 Three distance/time graphs are sketched below. a 8 © distance distance distance time time time @ Which graph (A, B or G) represents the movement of an object whose speed is decreasing? b Look at the distance/time graph below. It shows the movement of a car travelling at constant speed along a road. Add a second line to represent the motion of another car which is also travelling at constant speed, but ‘more slowly than the first car. distance time 20 treasinenotion @)@® Unit 10 Measuring motion 3. A railway timetable can provide information which can be turned into a distance/time graph. The timetable below shows some of the stopping points of the Himehal Express, a train that runs northwards from Delhi to Himehal in India. Delhi 22:05 Sonipat 23:52 4 o7 | ‘Samalkha 0014 n 89 Karnal (01:06 323 ‘Ambala City | 03:14 205 Morinda 04:38 275 Ghanauli 05:30 308 Nangal Dam | o735 355 7 | UnaHimchal | 07:50 (arrival) 7 Complete the last column to show the time since departure from Dehli.Unit 10 measuring motion (@® b Use the information to draw a distance/time graph for this journey. € Calculate the average speed of the Himchal Express. 20 tresuinenoion (@)@® Unit 10 Measuring motion Exercise 10.5 Allin a graph This exercise illustrates how much information you can extract from a distance/time graph ‘The graph below (also shown in your coursebook) represents a cyclists journey a hill and down the other side, up Se ah as PR a8 1500 i | distance/m 1000 eB es nee seo ~ | 0 50«100-«150:«200«-280 300 time/s 4 Insection A of the journey, the graph is a straight line sloping upwards. This shows that the cyclist is moving at a steady speed. How far does the cyclist travel during section A? ... How long does section A take? ....... © Calculate the eyclis’s speed during section A. @) 20 tersusng natnUnit 10 Measuring motion ‘® 2 These questions are about section B of the journey. a — How can you tell from the graph that the cyclist is travelling at a steady speed? b How can you tell from the graph that the cyclist is travelling more slowly than in section A? © Why's the cyclist travelling more slowly? culate the eyclist’s speed during section B. 3. This question is about section Gof the journey. How can you tell from the graph that the cyclist is stationary (not moving)? 40 Measuring motion ©@® Unit 10 Measuring motion 4 These questions are about section E of the journey @ How can you tell from the graph that this is the fastest section of the journey? b Why's the cyclist travelling most quickly in this section? culate the eyelist’s speed during section E. 5, Put the sections of the journey in order, from slowest to fastest Fastest @) 1 veosnra neroExercise 11.1 Making music This exercise will help you to understand how different sounds can be produced using musical instruments. ‘Musicians can play many different notes on their instruments. They can play loud notes and sofi notes. They can play high-pitched notes and low-pitched notes. Your task is to interview a musician about how they play their instrument, (You may be able to answer the questions for yourself if you play an instrument.) in the spaces below with answers from your interview. 40a Name of instrument b Name of musician € Type of instrument (stringed, wind, percussion)@® Unit 11 sound 2 How can the musician change the loudness of a note? 3. How can the musician change the pitch of a note? Explain what change: produce a note with a higher pitch, ® 44 SoundUnit 11 sound @® Exercise 11.3 The speed of sound In this exercise, you will interpret information about the speed of sound. How fast does sound travel? When someone speaks to you, you can hear what they say almost as soon as they start speaking, Iv’s bit different if you see a lighting strike. The thunder and lightning are produced at the same time, However, you see the flash first, A lite later, you hear the thunder, This shows that sound (thunder) travels more slowly than light (the flash of lightning) 1. The picture shows an experiment to measure the speed of sound. The person with the timer starts it when he sces the smoke from the starting pistol and stops it when he he: s700m sons ©@® Unit 11 sound The timer shows 5.0 when the person stops it Use the information in 1 sound in air, picture on page 101 to caleulate the speed of Distance travelled by sound Time taken = Speed of sound in air = b How far would sound travel at this speed in 108? ¢ Do you think this is an accurate way to measure the speed of sound in air? Explain your answer:2 The table shows the speed of sound in different substances, air 330 water 1500 concrete 3000 steel 5000 @ Does sound travel faster in steel or in water? Unit 11 Sound @® b Sound travels twice as fast in concrete as in water. True or false? © Whales call to each other when they are underwater. Their calls can travel very long distances. How long will it take for a whale call to reach another whale at a distance of 60 km? sins ©Exercise 11.4 Louder and louder interpret data concerning the loudness of soun ‘Our ears can hear a great range of sounds, from very soft to very loud. The Iouciness of a sound is measured on a scale called the decibel scale. The decibel (AB) is the unit of loudness. ‘The diagram below shows the scale and shows some typical sources of sounds with their loudnesses. Answer these questions, based on the diagram 1, Which end of the scale (left or right) has the loudest sounds? 2 Which is louder, a car or a motorbike? 3. According to the diagram, what is the loudness of a television set? 4 ‘The diagram shows that the loudness of @ conversation is about 50¢B. Do you think that all conversations have the same loudness? Explain your answer.Unit 11 sound @® 5, Loud sounds can damage your hearing. Could a crying baby cause damage? Explain how you can tell from the diagram. 6 Explain why people who work at an airport may have to wear ear protectors 7 Sounds louder than 90dB can damage hearing. Young people can damage their hearing by listening to music that is too loud. ‘They may do this by turning up the volume of their headphones, or by standing by the loudspeakers at a concert or at a club, In the space below, design a poster to encourage young people to look after their hearing by avoiding listening to loud music. sone ©@® Unit 41 sound Exercise 11.5 Range of hearing In this exercise, you will interpret data concerning the different frequencies of sound which we can hear. he frequency of a sound tells us the number of vibrations per second in a sound wave. Frequeney is measured in units called hertz (Hz). 1 Hz = | vibration per second. High frequencies are measured in kilohertz (kHz). I kHz = 1000 Hz = 1000 vibrations per second. ‘The range of human hearing is from 20 Hz.to 20000 Hy. 1 What is 20000 Hz in kHz? 2G uld a person with normal hearing hear a sound of 45 kHz? As people get older, their range of hearing decreases. The graph shows how the highest frequency which can be heard decreases as someone gets older. 2% upper limit of H hearing / kHz 5 PEE 5 | o 1 20 30 40 age /years 3. What is the highest audible frequency when a person is 60 years old? 4 Atwhat age does the range of hearing start to decrease? ...-..... 5 Could a person aged 40 hear a sound of frequency 15kHz? .. ©) 2Unit 11 sound @® Mice can hear sounds with frequencies between | KHz and 70 kHz. 6 Are there frequencies which mice can hear but humans cannot? 7 Which frequencies can humans hear but mice cannot? ....... The picture above shows an experiment to find out the highest frequencies which students can hear. 8 On the picture, label the signal generator and the loudspeaker. When the teacher turns the dial, the frequency of the sound from the loudspeaker increases. The students put their hands down when they can no longer hear the sound, 9 Some students have their hands up while others have put their hands down, What conclusion can you draw from this observation? 10. The teacher suspects that some students are not giving honest responses; they are keeping their hands up even when they can no longer hear the sound, How could he check if he is right? 44 Sound ©Exercise 12.1 Travelling light In this exercise, you will use and interpret information about how light travel: 41 We can see objects that are luminous. They are sources of light. 6: Oo a Name the Inminous objects shown above. b Name some other luminous objects: fone in space sere one in your home ... one that is a living creature ....... € Are you a luminous or non-luminous object? «+... Explain how a friend can see you on a sunny day @® 2mUnit 42 tight @® 2. How fast does light travel? It travels very fast indeed. Barly scientists found it very hard to measure the speed of light. ‘The picture shows how Galileo tried to measure the speed of light in the seventeenth century. n~—ees (This method works ) (fine for sound but \ not for light! ) ae + His friend stood on a distant hill, + Galileo flashed his lamp and started his clock at the same moment. + When his friend saw the light, he flashed his lamp back towards Galileo. + When Galileo saw the flash, he noted the time taken on his clock. Unfortunately, this method didn't work. This was because the light travelled very quickly from one hill to the other. It took only a tiny fraction of a second. It took much longer for his friend to see the light and react to it, flashing his own lamp, This method would work quite well if Galileo wanted to measure the speed of sound. If his friend was 3000 m away, how long would the sound take to travel between the two hills? The speed of sound is about 300 m/s. zn ©@® Unit 12 Light b Light travels one million times faster than sound. How long would light take to travel from one hill to the other? © How quickly can you react when someone flashes a lamp? Suggest how you could find out an answer to this question. @) 200Unit 12 Light (@® Exercise 12.2 Shadows use what you have learnt about how shadows form. 2 Shadows form when light is blocked. The picture below shows a scene on a sunny day: Your task is to show where there will be shadows on the ground. \ ‘The Sun is shining, ‘Two rays of sunlight are shown. They are parallel to each other. Add to the picture by drawing more rays of light. Remember that they must all be parallel to each other. Use a black pen or pencil to mark the areas on the ground where there will be shadows. 2 In the middle of the day, the Sun is much higher in the sky and shadows are much shorter. On the picture below, draw parallel rays of sunlight at midday and mark where the shadows will be.@® Unit 12 Light 3 When the astronomer Galilco first looked through a telescope at the Moon in 1609, he sav that its surface was covered in mountains and craters. He could see these because they were lit up by sunlight and they had very clear shadows. Your task is to find some photographs or drawings of craters on the Moon. Study them carefully and, in the space below sketch a typical crater and label the shadows. Draw an arrow to show the direction of the sunlight which is lighting up the crater. ® 22 LightUnit 12 tight ® Exercise 12.3 Seeing by reflection In this exercise, you will evaluate statements about how we see by reflected light. We see things because light rays travel from them into our eyes. The picture shows a boy looking in a mirror. The girl can also see the boy. Study each sentence below + If the sente correct, put a tick ( ¥ ) at the end. + If the sentence is incorrect, cross out the incorrect words and, in the space below, write words which will make the sentence correct 4. The lamp is a non-luminous object 2. Light from the lamp spreads out into the room. zon ©3 Light rays travel from the gin!’s eyes to the boy’s hair 4 The boy can see an image of his hair in the mirror 5 Angle Qis greater than Angle P 6 The law of reflection allows us to predict the direction of a ray of light when it is reflected by a flat mirror. ® 22: UattUnit 12 tight (@® Exercise 12.4 Refraction of light In this exer you will apply what you have learnt about how light is refracted. 4. Complete the sentences below using the phrases in the box. bends towards the normal. passes from one material to another. must be wansparent. a If light is to pass through a material, the material... b Refraction is the bending of light when it € When a ray of light passes from air into glass, it. 2. Complete the diagrams to show how each light ray will travel.@® Unit 12 Light Exercise 12.6 Coloured light ht and colour to In each part of this exercise, you will be given some information. You will have to answer one question, based on the information (a). You will also have to devise two quiz questions of your own, and give the answers (b and ). 1 The diagram shows how a spectrum of white light can be produced, using a prism, @ What colour is at the opposite end of the spectrum to red?Unit 12 2 The diagram shows what happens when different colours of light combine. ‘This is colour addition. magenta cyan yellow blue green red @ What two colours combine to give yellow light? Light ® 2un @@® Unit 12 Light 3 The diagram shows what happens when white light falls on a blue object, Blue light is reflected. This is colour subtraction. white light @ What colours of light are absorbed when white light falls on a green object? 4 A red filter lets red and orange light pass through. It absorbs the other colours of light, @ White light shines through a red filter on to a blue car: What colour will the car appear?Exercise 13.1 Magnets and magnetic materials This exercise will help you to check that you know how different materials behave when you bring a magnet close to them. 4 Mohammed is testing different materials to discover which are magnet @ Write a sentence to describe what he should do. b_ The table shows the items he tested. Indicate in the second column whether each item would be attracted by a bar magnet (tick) or not attracted (cross), copper coin steel paper clip aluminium foil tray plastic cup wooden stick iron nail ‘water in a cup ¢ Name another item that would be attracted by a permanent magnet. Name another item that would not be attracted by a permanent magnet. 43: Naame ©( ® Unit 13. Magnetism 2. The picture shows the corner of the door of a refrigerator. refrigerator door magnetised strip. fastened to refrigerator door steet case of Explain why the door stays shut after it has been closed. ]) 13 vseUnit 13. Magnetism ® Exercise 13.2 Magnetic forces, making magnets This exercise will test how well you understand what happens when magnets and magnetic materials are brought close together. 1. Nikita’s teacher gives her some pieces of metal to test. They have been wrapped up so that Nikita cannot tell whether they are magnets or not. object A object B object ¢ object D object x object @ Nikita brings objects A and B close together. ‘The objects attract each other. Nikita writes: ‘Objects A and B are both permanent magnets, because they attract each other.’ Do you agree with Nikita? Explain your answer, b Nikita brings objects € and D together: The objects repel each other. What can you say about objects € and D? Explain your answer. 3 ven @@ Unit 13. Magnetism © Nikita brings objects X and ¥ together: The objects neither attract nor repel. Nikita writes: ‘Neither X nor Y is a permanent magnet. Nikita might be right but she might be wrong. Explain how you would test her answer to see if she is correct. 2 Why does a piece of iron become magnetised when you stroke it with a permanent magnet? Scientists imagine that a piece of iron is made up of many tiny regions called domains. Fach domain behaves like a tiny magnet with its own magnetic field + Ina piece of unmagnetised iron, the domains are all jumbled up. Their magnetic fields cancel each other out + When the iron is stroked with a magnet, each domain is attracted by the magnet, The domains all «urn round so that they become lined up. Then all their magnetic fields add together to make a strong field. a Look at the diagrams below. The arrows represent the magnetic domain: Underneath the diagrams, add labels: unmagnetised iron and magnetised iron. 7 tts aa s5 ere Sao a ® 43. MagnetismUnit 13 Magnetism (@® b The next diagram shows what happens when a bar magnet is cut in half. 233] Describe the result of cutting a bar magnet in half like this,Exercise 13.3. Representing magnetic fields c fields exercise will help you to understand how we represent magni 1g magnetic field lines. 4. The picture below shows the magnetic field around a bar magnet. oO a Onthe diagram, label the north (N) and south (S) poles of the magnet. b Explain how you know which is the north pole. € The two circles on the diagram represent compasses. Draw the needle of cach compass, showing how it will line up in the magnetic field of the magnet, d__ Explain how you can tell from the diagram that the magnetic field is, strongest close to the magnet’s poles. @Q) 23 wsr00Unit 13 Magnetism (@® @ Inthe diagram below, you can sce the outline of a bar magnet, Using a pencil, shade the area around the magnet to show how strong the magnetic field is. * Use dark shading to show where the field is strong. + Use light shading to show where the field is weak. f Give a reason why field lines are a better way of showing a magnetic field pattern than shading. 23 vsnein &@® Unit 13. Magnetism 2. The diagram below shows two magnets. On the diagram, label the north (N) and south (8) poles of each magnet. b Are the magnets attracting or repelling each other? Explain how you know. € Add force arrows to the diagram to show the force each magnet exerts on the other. Label the arrows ‘force of A on B’ and ‘force of Bon A’ d_ Imagine that you could place a compass exactly half’ way between the two magnets, Add an arrow to the diagram to show how its needle would point, G) 22 wowsUnit 13. Magnetism @® Exercise 13.5 | Magnets and electromagnets This exercise will test your understanding of permanent magnets and electromagnet: ‘h statement below is incorrect. Gross out the incorrect part of each statement, In the space below, write a correction so that the statement is correct. A bar magnet has a north pole at one end and a west pole at the other. 2 The north pole of a magnet is attracted to the Ea th’s south pole. 3 A bar magnet needs an electricity ipply to make it work 4 The core of an electromagnet must be made of a non-magnetic material 5 An electromagnet remains magnetised when the electric current in its coils is switched off. 6 Decreasing the current i field stronger. an electromagnet will make its magnetic 3 neswin ©@® Unit 13 Magnetism Exercise 13.6 Revising magnets and electromagnets This exercise will test what you have learnt in this topi Here are some terms that you have learnt while studying magnetism. magnetic field electromagnet magnetic pole magnetic field line ammeter core compass like poles 1. The table below shows definitions of four of these terms. Write the terms in the spaces in the first column, 2. Now write the remaining four terms in the other spaces in the first column, Write a definition of each of these in the second column. a permanent magnet which can turn freely in the Earth's magnetic field ‘two north magnetic poles, or two south magnetic poles an instrument used to measure electric current a line drawn to show the direction of a magnetic field ® 43 MagnetismCambridge Checkpoint Science Workbook 8 e Mary Jones, Diane Fellowes-Freeman and Navid Sang Cambridge Checkpoint Science Workbook 8 matches the requirements of stage 8 of the revised Cambridge Secondary 1 curriculum framework. It is endorsed by Cambridge International Examinations for use with their programme. The series is written by a highly experienced author team. This accessible Workbook is intended to be used alongside the Cambridge Checkpoint Science Coursebook 8. It contains exercises that will help students develop the skills they need to succeed with the Secondary 1 programme. The Workbook aims to develop a range of sI + applying knowledge planning investigations ‘* recording and interpreting results. ‘Answers to the exercises are included on the Teacher's Resource CD-ROM 8. Other components of Cambridge Checkpoint Science 8: Coursebook 8 ISBN: 978-1-107-65935-3 Teacher's Resource 8 —_ISBN: 978-1-107-62505-1 Completely Cambridge - Cambridge resources for (oui Cambridge qualifications Se Cambridge University Press works closely with Cambridge International Examinations as parts of the University ‘of Cambridge. We enable thousands of students to pass their Cambridge exams by providing comprehensive, high-quality, endorsed resources. To find out more about Cambridge International Examinations visit www.cie.org.uk Visit cambridge.org/cie for information on our full range of Cambridge IGCSE titles including e-books and supporting digital resources. ML STerW th areal ean YBa ea ac SBN 978-1-107-67964-0 Eee a CAMBRIDGE jini seats 9 781107"679610">