Sciasp1cb Ch01 4Pp.Indd

Working scientifically 1

Investigating experiments as fair tests dependent, independent and controlled variables in experiments the importance of replication and repeat trials in experiments science skills of observing, measuring, classifying and recording data equipment and safety in the science laboratory how evidence, experiments, what is known, and being creative and critical help in science Curriculum guide learning focus Communicating scientifically using scientific terms written and spoken reports for different types of audience collecting, evaluating Sample pages and displaying scientific information Science in daily life using science to solve problems in everyday life understanding that there are alternative scientific arguments and theories Science in society Outcome level descriptions Acting responsibly how science and the rest of society The outcome level descriptions the effects of science on affect each other the environment for Investigating covered in this the value that the scientific section of the book are mainly I 2, monitoring the effects of community places on honesty, I 3 and I 4. science reasoning and respect for evidence FOCUSFOCUS 11..11 Science is a word you often hear or read. On of science are everywhere and it is a vital part of our the news scientists are reported as making new lives. This is why every educated person needs to discoveries which change our world. You often know about science. It is certain that science will go hear about science in science fiction movies or on changing our lives at an ever-increasing speed. on television. Many devices, such as the mobile

Context Those who do not understand it will be left behind. phone, television and compact disc player, are This is why it is important to study science at school. based on scientific discoveries. Medical advances are largely carried out by scientific research. The effects

Integrated circuits enabled the development of Fig 1.1.3 electronic devices.

What is science? One part of the answer is that science is a store of knowledge. Science is also a way of finding answers to questions. Fig 1.1.1 Science affects many areas of our lives. The MRI machine enables doctors to look inside our bodies. Science as a store of knowledge Hundreds of years of using a scientific approach have resulted in the accumulation of a large body Sampleof scientific pages knowledge. The total extent of this knowledge is now more than any one person can ever hope to learn. For example, we know how the heart works, what makes stars shine, why children look like their parents, why some chemicals explode and how a virus can make you ill. But there are many things we do not know enough about, such as how the human brain works, or all the causes of cancer, or whether life exists on other planets. The thrill of science is that we can discover new information. The branches of science The study of science is divided into smaller sections, This X-ray shows a heart pacemaker used to Fig 1.1.2 called the branches of science. Usually a scientist regulate a person’s heartbeat. becomes a specialist in one of these branches.

3 What is science? >>>

There are four main branches Let science help asthma attacks, how animals can navigate over long of science. If you learn about science distances, how to cure diseases such as AIDS and how d our 1 Biology is the study of you will understan to prevent pollution of the environment. world a lot better. It can living things. It has two help you make decisions Some questions take many years to be answered. main sub-sections. Botany about how you live and We may have to do many experiments to find answers.

is the study of plants, and the things you do. It can help you make the world Saving endangered species from extinction zoology is the study of a better place for all. You Fig 1.1.5 is an important goal of science. animals. People who study may be surprised to learn biology are called biologists. that people in many types tific 2 Geology is the study of the of jobs use scien knowledge—for example structure of the Earth and electricians, mechanics, of the rocks and minerals pilots, nutritionists and aches. of the Earth’s crust. People sports co who study geology are called geologists. 3 Chemistry is the study of the tiny particles from which all the living and non-living materials of the Universe are formed, and how these materials can change and affect each other. People who study chemistry are called chemists. 4 Physics is the study of the behaviour of matter and energy. When you study physics you will learn Some questions may never be able to be answered by about sound, electricity, light and heat. People who science. So science does not have all the answers to study physics are physicists. every question we may ask. There are many ways of finding the answers to our questions. Science investigations come in a variety of different forms but the key approach or method that science uses to discover answers is the ‘scientific method’. You will learn about many of the variations on this method over the next few years. Scientific method The scientific method is a series of steps used to discover new information. While there can be some Samplevariations pages in this method, most scientists would agree the process generally consists of the following steps. 1 Making observations Fig 1.1.4 Microscopes are most widely used in the We make observations using our senses of sight, branches of biology, but can be used in hearing, touch, smell and taste. More accurate other fields. observations need measuring instruments such as thermometers and clocks. Science as a way of answering 2 Posing a question Scientists are curious people. They want to know questions why. So the next step is to ask why something Science is also a method by which we can find the happened. answers to questions about the world around us. 3 Making a hypothesis A method is a series of steps or rules to follow to A hypothesis is a possible answer to the question. discover an answer to a question. Some questions You use your knowledge of science to decide that science is trying to answer include what causes what the answer to the question is likely to be.

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This is where knowing quite a lot of science is really useful. A guess is a ‘lucky shot’, when you 9 What type of scientist would work in each of the don’t know anything about the subject concerned. following situations? FOCUS FOCUS A hypothesis is not a guess, as you use your a an oil drilling company knowledge to help you decide on a likely answer. b a plastics factory 4 Testing the hypothesis c a plant nursery The hypothesis is then tested to see if it is backed d a company that generates electricity up by evidence. You are trying to find out if it e a company that builds aircraft seems to be correct or not. This test is usually f a zoo done by an experiment. Sometimes a second g a gold mine. hypothesis has to be put forward if the first one is 10 Consider each of the following quotes. Indicate which not supported. step of the scientific method each one represents. 5 Making a theory a ‘… before you base a law on this case, test it two If a hypothesis is tested many times and is found or three times to see whether the tests produce the same effects’ (Leonardo da Vinci) always to be supported by evidence it may be b ‘Once you have asked the right question, many called a theory. An example of a theory is the likely answers become obvious’ (Karl Kruszelnicki) atomic theory, which is about all matter being c ‘… all sciences are vain and full of errors … that made of very small particles called atoms. do not … pass through any of the five senses’ This is only a brief outline of the scientific method. (Leonardo da Vinci). You will look at it in more detail in later foci. 11 Imagine you discover a dog with a cut and bleeding paw. The cut is 3 centimetres long and has clean, sharp edges. Indicate which of the following hypotheses are . likely to explain this, and give reasons for your answers. 1 1 [ Questions ] a The dog stood on a piece of wire. b The dog bumped its paw against a wall. Use your book c The dog caught its paw in a door. Science as a store of knowledge d A cat slashed it with its claws. e The dog stood on a sharp object like a piece of 1 Give two answers to the question ‘What is science?’ FOCUS sheet metal. In which branch of science do you study: 2 f Someone stood on the dog’s paw. a animals and plants? 12 Consider your answer for Question 11 above. b plants? a What would your answer be if you were told the dog c light and sound? had been inside the house all day? earthquakes? d b Do you need a new hypothesis? Science as a way of answering questions 3 Do science investigations all use the same method? Investigating questions 4 What do we mean when we saySample science is ‘a way of 13 Findpages out what work is done by scientists who work as: answering questions’? a archaeologists c biochemists The scientific method b entomologists d engineers. 5 Rearrange the letters in the following jumbled-up words to 14 Name two current problems that scientists are trying make words in the scientific method, and put the words to solve. You might need to look through some in the correct order : stqeunio, pythishsoe, onsebriovat, newspapers or on the Internet for information. pertixemne. 15 Watch the news on television or listen to the radio 6 What do we mean by a hypothesis? news. Briefly describe one story which was about 7 Is a hypothesis a wild guess? science. 16 Which branch of science you would have to study Use your head to be: 8 a Identify three items at your school that you think may a a doctor e a veterinarian have been produced by a scientist. b an electrician f a computer technician b Indicate the type of scientists who probably helped to c a physiotherapist g a nurse produce these items. d a pharmacist h a pilot?

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For the next three to five years you will be using science equipment and science laboratories to study science. You need to learn about the equipment you will be using. Science can be a dangerous subject and so Context requires you to learn about working safely. Safety rules are vital in science. This focus will help you learn the names and uses of science equipment and the safety rules needed to protect you and your friends.

Safety features in the science laboratory A science laboratory is a room in which science activities are done. Many people work in science laboratories in hospitals, universities, large industrial Fig 1.2.1 A fire extinguisher complexes and factories and special research facilities. The following safety features are common to most laboratories. • Main gas and water taps. Usually a laboratory will have a gas shut-off valve and a main water tap so that all the gas and water can be turned off in an emergency. There usually is a master switch to turn off all the electricity. Make sure you know where it is. • Exhaust fan. Chemical laboratories usually have an exhaust fan to remove dangerousSample fumes. pages • Emergency exits. In a laboratory there are usually at least two exits that can be used in an emergency evacuation. • Fire extinguishers. Fire extinguishers are available in case there is a fire in the laboratory. You should learn how to use a fire extinguisher as you may have to use one in an emergency. Safety glasses are essential to protect your eyes. Fig 1.2.2 • Fire blanket. A fire blanket is a non-flammable blanket which can be thrown over a fire to put it out or to wrap up a person whose clothes are on An eyewash should be available in case of fire. Non-flammable means that it will not catch accident. An eyewash is a bottle of water, which fire or burn with a flame. you can use to wash out any chemicals that have • Eye protection. Safety glasses should be used accidentally splashed into your eyes. Make sure whenever your teacher advises you to wear them. you know where yours is. 6 11..22

Laboratory rules Science rules! Laboratory equipment The main rules for the Laboratory rules are to You will learn the names and uses of the different pieces FOCUS laboratory are the following: protect everyone, including of equipment as your study of science continues. Below FOCUS you and your friends. Y 1 Be careful when moving ou is a list of common pieces of laboratory equipment that must learn these rules and around the laboratory. follow them at all times. you will use regularly during your science course. 2 Tie back long hair and wear Find out if your teacher has You can see what they look like in Figure 1.2.3. protective glasses. given you a list of extra rules 1 Test tubes are used for holding small amounts of for your class. You may 3 Wear covered footwear. need to keep a copy in your chemicals. Thongs are not acceptable science notebook. Find out 2 Beakers are used for holding larger amounts of footwear. why your teacher wants you substances. They can be used when heating liquids. 4 Only do experiments to follow these extra rules. 3 Measuring cylinders are used to measure volumes directed by your teacher. of liquids. 5 Report accidents, breakages and damaged equipment. 4 Filter funnels are used for pouring liquids into 6 Clean up and return equipment when finished. narrow containers, and for filtering solid particles 7 Do not wash solids down the sink. out of liquids. 8 Listen carefully to your teacher’s instructions. 5 Flasks are used in some experiments in which liquids are used. They may be round-bottomed, Homework book 1.1 Commonsense safety rules flat-bottomed or conical.

test tube mortar and holder pestle beaker filter funnel test tube tongs

measuring watch-glass cylinder clamp gas jar and lid

Sample pagesretort stand boss head round-bottomed flask test tube rack

pipeclay triangle

conical flask

tripod filter stand

Bunsen burner evaporating basin

flat-bottomed flask wire mat spatulas

Fig 1.2.3 Some science equipment used in school laboratories

7 Equipment and safety >>>

6 Watch-glasses are small dishes used for holding Fig 1.2.4 How to sketch science equipment small specimens, and for helping liquids to evaporate quickly. 7 Bunsen burners burn gas to heat substances. 8 Tripods are stands with three legs. When a beaker tripod is heated on a Bunsen burner, a wire mat is placed filter beaker on the tripod, and the beaker is placed on the wire funnel retort mat. The wire mat spreads the heat evenly. test tube stand 9 Bench protection mats are placed under the equipment to protect the bench. 10 Retort stands and clamps are used for holding wire mat clamp equipment. The boss head holds the clamp to the conical boss head retort stand. Bunsen flask measuring 11 Tongs and test tube holders are used for holding burner evaporating basin watch-glass cylinder hot objects, such as a test tube being heated over a Bunsen burner. 12 Test tube racks are for holding test tubes. 13 Pipeclay triangles are used for holding containers such as crucibles when they are being heated by beaker a Bunsen burner. 14 Spatulas are used for picking up solids and putting water them into containers. 15 Gas jars are used for holding gases produced in wire mat experiments. 16 A mortar and pestle are used to grind up solids into a powder. The mortar is the bowl-shaped piece. tripod 17 Filter stands are used for holding filter funnels. 18 Evaporating basins are used to evaporate liquid quickly. Bunsen There are, of course, many other specialised pieces burner of equipment. You will learn their names and uses as you progress through this book. Some of these are stethoscopes, van der Graaf generators, How to sketch and label equipment Fig 1.2.5 dissecting instruments, microscopes, used in an experiment electrical meters, thermometersSample and pages manometers. your diagrams. This means you must write the name of each piece of equipment next to it and join it to the Homework book 1.2 Science equipment wordfind diagram with an arrow or line. Homework book 1.3 Identifying science equipment Using a Bunsen burner Lighting Sketching equipment Figure 1.2.6 shows a Bunsen burner. When using a You always draw a piece of laboratory equipment Bunsen burner you should follow these steps: as though it has been cut from top to bottom in the 1 Clear the work area and place a bench protector middle and you are looking at it from the side view. under the Bunsen burner. This is called a vertical transverse section. Figure 1.2.4 2 Close the air hole of the burner by turning the collar. shows you how to sketch some laboratory equipment. 3 Light a match and hold it at the top of the burner, Figure 1.2.5 shows you how to sketch equipment but not directly over the hole. set up for an experiment. You must always label 4 Turn on the gas and light the burner.

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5 Leave the collar closed and the yellow luminous Safety flame burning until a hot flame is needed. Here are some very important safety rules to follow 6 Slowly turn the collar around to open the air hole FOCUS

when using a Bunsen burner: FOCUS if you need a hotter flame. If the burner flame goes 1 Always follow the steps described above when out, turn off the gas and start again. lighting a burner. 2 Do not lean over a burner because your hair or clothes could catch alight or you could be burnt. top 3 When not using the burner for heating close the collar to produce the yellow luminous flame—it is barrel easier to see and there are less likely to be accidents. 4 When heating a test tube over a burner make sure that the open gas inlet end is not pointing at anyone in collar case some of the contents spit Prac 1 Prac 2 air hole p. 10 p. 10 out of the test tube.

base Sketching equipment Fig 1.2.6 The parts of a Bunsen burner 8 Sketch and label a diagram that shows a flat-bottomed flask clamped to a retort stand and being heated by a Bunsen burner. The bottom of the flat-bottomed flask is Homework book 1.4 The Bunsen burner just touching a wire mat, which is on a tripod stand. Using a Bunsen burner . 9 Why should the Bunsen burner be left burning with a 1 2 [ Questions ] yellow luminous flame when it is not being used for heating? Use your book 10 What is the important rule to follow when heating liquid in a test tube? Safety features 11 Why should you light the match before turning the gas 1 Name four items in a science laboratory that you would FOCUS on when using a Bunsen burner? not find in other classrooms. 2 Where are the main gas shut-off valve tap and the main Use your head water tap in your laboratory? 12 What five rules do you think are the most important? 3 Where are the exits from your laboratory that could be Give your reasons. used in an evacuation? 13 What would you do if you splashed some acid in your Laboratory rules eye? 4 Write down any five rules youSample remember. Now check your 14 Whypages must you tie back long hair and be careful not to book and write down any rules you could not remember. lean over a Bunsen burner when it is burning? 5 If you are doing an experiment and you break some 15 If you had a test tube containing a solid and some glassware, what should you do? liquid, what should you do to clean it? Laboratory equipment 16 Why is it especially important in science rooms that you 6 Give the uses of the following pieces of equipment: wire are well behaved and thinking about what you are doing mat, spatula, tongs, evaporating basin. at all times? 7 Use Figure 1.2.3 to answer the following questions: 17 Why do you think so many of the containers and a What six glass containers can be used to hold liquids? vessels used in a laboratory are made of glass? b What piece of equipment can be used to measure the Investigating questions volume of a liquid? c What would you use to hold a clamp to a retort stand? 18 What instructions are written on the side of the fire d What would you use to hold a hot test tube? extinguisher in your laboratory? e What would you use for pouring water from a beaker 19 What are the evacuation procedures for your science into a narrow container? classroom?

9 Equipment and safety >>>

1.2 [ Practical activities ]

Bunsen burner flames How to mount the match on the pin Fig 1.2.7 Purpose Prac 1

FOCUS To investigate the properties of different Bunsen Focus 1.2 burner flames Requirements Bunsen burner, matches, 2 test tubes, water, tongs, 2 nails, unburnt gas pin pin Procedure 1 Light the burner and leave the collar closed. The flame match produced is called the luminous flame. Describe the Bunsen burner appearance in your notebook. 2 Hold a clean test tube half full of water in the flame for about 20 seconds. Record the appearance of the test tube. 6 Push the pin through a match and place it in the Bunsen 3 Using the tongs, hold a clean nail in the flame for as shown in Figure 1.2.7. Then light the Bunsen burner 20 seconds. Record the appearance of the nail. and switch to the blue flame. Record what you observe. 4 Open the collar to produce a blue flame. The flame Questions produced is called the non-luminous flame. Notice it has two areas, a darker blue inner cone and a lighter blue 1 Which flame do you think is hotter? Give your reasons. outer cone. Draw the appearance of the flame. 2 The luminous flame is also known as the dirty flame. 5 Repeat steps 2 and 3 with the blue flame, holding the Which of your observations showed this? object a few centimetres above the tip of the inner cone. 3 Which is the safer flame if you have to leave your Record the appearance of the test tube and the nail. Bunsen burner alight? Give two reasons.

Doing an experiment with the Bunsen burner

Purpose 3 Loosen the boss head and lower the clamp so that the Prac 2 To do an experiment using the Bunsen burner. bottom of the thermometer is in the middle of the water, Focus 1.2 You will find out whether water keeps on about halfway between the surface and the bottom of becoming hotter if you Samplekeep on heating it. thepages beaker. Requirements 4 Copy the table below into your notes and then record the temperature of the water in the table. Add as many 250 mL beaker, tripod, wire mat, Bunsen burner, 110°C rows as you need for your records. mercury thermometer, retort stand, boss head, clamp, one-hole stopper, clock or timer, safety glasses, matches. Temperature change while heating water >> Procedure 1 You will be setting up your equipment as illustrated in Time Temperature Observations Figure 1.2.8. However, you need to read through steps (minutes) (°C) 2 to 4 below before you set up the equipment. 0 2 Very carefully push the top of the thermometer into the 1 hole in the stopper so that it holds the thermometer. 2 You must still see the 100°C mark. Fix the stopper into the clamp and attach it to the retort stand. Be very 3 careful not to break the thermometer.

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5 Put on your safety glasses. Light the Bunsen burner, following the correct steps. FOCUS

6 Using the hottest flame, heat the water. Record the FOCUS

90 0

11 temperature every minute until the water boils. Note 80

100 stopper 7060 how the water appears in the ‘observations’ column. clamp

50 thermometer 7 Continue recording the temperature for three minutes

after the water boils.

0 3

20 beaker

10 Questions 0 1 Did the temperature rise through the whole water experiment? 2 When did the temperature stop rising, and what did you see was happening to the water at this time? wire mat 3 Pure water boils at exactly 100°C, measured with an Bunsen accurate thermometer. Does your experiment suggest burner anything to you about tap water?

tripod 4 Your teacher could do a demonstration with distilled water, or they may let you try it yourself—though distilled water is expensive. retort stand

Fig 1.2.8 Set up your equipment as illustrated in this diagram.

Sample pages

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We discussed the scientific method in Focus 1.1. What was the first part of this method? If you said ‘observation’, you were correct. All science is based on observation as the first step. Making careful and accurate observations Context is the beginning of the process of trying to explain the world around us. You have to practise observing to become good at it. You also need to understand the process of measurement, which is using instruments to find a number.

Observation An observation is information gained from your senses. Your five main senses are sight, hearing, touch, taste and smell. When you use any of your senses to detect something, you are therefore making an Fig 1.3.1 Wafting is the method used for smelling observation. chemicals. Taking care with our senses Extending the senses You must use your senses of smell, taste and touch In science you can use instruments to help extend carefully in science laboratories. It is not wise to taste your senses to make observations. unknown chemicals, or even familiar ones. There is You can extend your sight with microscopes, always the chance that they may be contaminated. telescopes, hand lenses and other devices. This means they may have been mixed with other You can extend your hearing with a stethoscope. chemicals, which could be poisonous. Doctors use these to hear sounds such as heartbeats. It is very important to be careful when touching things in the science laboratory.Sample Some chemicals pages are poisonous. A good rule to follow is not to touch chemicals with your skin unless you are certain they are harmless. Many objects you use in science are hot and can burn. Others can give an electric shock. When smelling things scientists use a method called wafting. You hold the substance to be smelled about 30 centimetres or so away from your nose. You then wave your hand towards and away from your nose to push the air from around the object towards your nose. In this way only a small amount of the substance is inhaled. If the substance is dangerous it will not do as much harm as if you Using a stethoscope to listen to chest sounds Fig 1.3.2 took a deep sniff.

12 f Build your gliders and carry out some preliminary trials h Report on your conclusions about the two on them. If they are flying poorly then you may need to independent variables you tested. identify the problem. You may have to reconsider your i Is the glider you have built the most cost-effective variables and change your design. What problems did glider for the job? How do you know? you have? Have you decided to try a different variable? g If you have fixed up any problems you had and the glider now appears to be flying, then do your trials and record the results.

[ Extended investigation/research]

3 You are a member of a group of scientists in a company d the steps you will take to determine the variables that is investigating setting up in the ‘super ball’ business. involved in making the ball You want to produce a super ball that will bounce as e how you will determine the ball quality high as possible. You have to find a good recipe in the f what jobs each person has in your group laboratory to make the ball. You have discovered from g how you will report your research findings. your reading that the ingredients of a super ball are PVA You need to hold discussions in your group first about glue, and borax solution, and that borax should not be all the points listed above before you even start trying ingested. To make a borax solution, borax powder must out any experiments. You may need to do a few small be dissolved in water, but you have no idea how much tests first and go back to modify your plan again. When powder you need to dissolve. You have heard verbal you have a fairly good idea of a plan to tackle this reports that you need to mix similar amounts of glue and task, talk to your company chief scientist (who looks borax solution, and that you have to stir them together. remarkably like a science teacher you had when you But you are not really sure how accurate these reports were a year 8 student). If the chief scientist is happy, are. You have decided to test two different PVA glues you can begin some preliminary experiments. The chief to see if one is better than the other. You must be wary scientist will monitor your progress and you need to give of wasting company money on large quantities of these them a regular verbal report on your progress. ingredients. It is also important that you are tidy and clean up any glue you spill. When all your experiments are done you need to clear up and then get down to the report writing. Your group needs to determine: The chief scientist will probably think you can achieve a how much of each ingredient you need all this in about four hour’s laboratory time, but you may b how you should mix the ingredients need to negotiate this. c what equipment you will use for your laboratory investigation Sample pagesHomework book 1.14 Working Scientifically crossword Homework book 1.15 Sci-words

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