questions 1. 1 1. List ten ways that you have used science 5. Make a cartoon strip or poster about one of today. the things you listed in question 1. 2. List ten things that you could not have 6. In a small group create a play or write a song done without scientists creating or making about using scientifi c skills in your everyday discoveries. life. Perform this for the class. 3. Which of the following are observations and 7. Look through a newspaper or magazine or which are inferences? Present your answers browse the Internet to fi nd an article that in a table. discusses scientifi c methods. Cut out or Aaron is 168 cm tall. print out the article and paste it into your The bushfi re was caused by lightning. workbook. Explain to your class what the Steven is stronger than David. article is about and what will be its benefi ts The population of Darktown is 1.2 million. or problems. Lanah’s cat weighs 2 kg. 8. Find some examples of how scientists use Jaimie is a faster runner than Soula. models. Explain what the model is for and 4. Every branch of science has a special name. how it helps our understanding. Can you match the names below with what they study? acarology fungi oology fruit anemology snakes ophiology mountains bryology clouds orology reptiles and amphibians dendrochronology wind palynology ants herpetology mouth disorders pomology rivers mycology fossil pollen potamology age of trees by rings myrmecology birds’ eggs pteridology mosses nephology fermentation stomatology dreams nosology ferns trichology classifi cation of diseases oneirology hair zymology mites and ticks 11.2.2 Working safely A science laboratory is a place where you can carry out scciifiilele investigations and conduct experiments. You have already learned that everybody can be a scientist and science is used all Experiments are carefully around us every day. So there are many places that can be called planned step-by-step practical activities, which can be science laboratories, not just your school laboratory or a research recorded and reported in many laboratory at a university, hospital or factory. different ways. A laboratory can be a source of accidents. So wherever your science laboratory is located it is essential that there are rules for your safety. Always ensure that you think before you act so that you don’t endanger yourself or others. 6 Science 8: A Contextual Approach 001_HQSP8_SI.indd1_HQSP8_SI.indd 6 112/5/062/5/06 33:48:25:48:25 PPMM SCIENCE work Activity 1.4 Recognising some science equipment What you need • Bunsen burner • test-tube brush • spatula • gauze mat • boss head and clamp • evaporating dish • test-tube • test-tube rack • watch-glass • fi lter funnel • test-tube holder • heatproof mat • measuring cylinder • tripod • pipe clay triangle • dropping pipette • tongs • stirring rod • retort stand • beaker • conical fl ask What to do 1. Divide the class into groups of two or three students. 2. Your teacher will give each group three pieces of equipment plus nine blank cards or pieces of paper. 3. The task for each group is to prepare a set of three cards for their equipment—‘equipment name’, ‘scientifi c drawing’, and ‘what it is used for’. 4. Each group presents their cards to the class and answers any questions about their equipment. 5. Cards can then be swapped between groups and used for matching activities. The Bunsen burner scciifiilele In a laboratory many experiments require heat. A Bunsen burner is often used to provide heat, and it is important that you are able to use it safely. Robert Wilhelm Bunsen did not actually invent the Bunsen burner At the top of the Bunsen —he just improved it. He made burner this mixture of gas and air can be much greater contributions to ignited to produce a areas of chemistry such as organic Opening and closing the air hole barrel flame, which is used to chemistry, arsenic compounds, changes the amount of air mixing heat substances. with the gas and so allows you to gas measurements and analysis, control the amount of heat the galvanic battery, elemental produced by the Bunsen burner. spectroscopy and geology. The amount of heat As gas moves into the Bunsen burner produced by the burner from the gas tap, air moves into the collar can be controlled by barrel of the burner through the air turning the metal ring or hole and mixes with the gas. collar at the bottom of the barrel. rubber tubing gas supply The base of the Bunsen burner can get very hot so the burner should Figure 1.7 always be used on a How does the Bunsen burner work? base heatproof mat. Steps for using a Bunsen burner: 1. Always use a heatproof mat. 2. Connect the gas tube to the gas outlet. 3. Close the air hole before lighting. 4. Hold a lit match beside the mouth of the barrel. Turn on the gas and move the match over the barrel to light the gas. 5. Open the air hole slowly. Set the air hole and gas for the fl ame required. 8 Science 8: A Contextual Approach 001_HQSP8_SI.indd1_HQSP8_SI.indd 8 112/5/062/5/06 33:48:31:48:31 PPMM SCIENCE work Using a Bunsen burner EXPERIMENT 1.5 Aim To learn to use a Bunsen burner safely. Materials • Bunsen burner • platinum or nichrome wire • matches • test-tube • heatproof mat • test-tube holder Method: Lighting the Bunsen burner 1. Your teacher will demonstrate how to use a Bunsen burner. You may need to write some notes or draw some diagrams. 2. Connect your Bunsen burner to the gas tap. 3. Close the air hole by turning the collar. 4. Hold a lighted match at the top of the barrel towards the side of the opening. 5. Turn the gas tap to the fully open position and move the match over the barrel to light the gas. 6. Note the appearance of the fl ame. This fl ame is called a safety fl ame. 7. Using the test-tube holder, hold the test-tube near the top and place the bottom of the test-tube into the fl ame. Observe the deposit that forms on the test-tube. Record your observations in your book. 8. Place the test-tube into the test-tube rack so that your bench is not damaged. Remember, it will be hot! 9. Slowly turn the collar of the Bunsen burner until the air hole is fully open. As you do so, working scientifically observe and report the changes in: (a) the amount of light and heat given off 01 (b) the colour of the fl ame (c) the size of the fl ame. Results and discussion Draw a fl ow chart showing the steps involved in lighting and using a Bunsen burner. Include any safety rules. chapter questions 1.2 1. Think about two laboratory safety rules you 2. Many chemicals can stain, irritate or burn consider important. the skin and some are poisonous. Many (a) Share your rules with a partner and make chemicals are only safe if used correctly. up a list of fi ve rules. What should you do in each of the situations (b) With your partner, decide on how you will listed below? share your rules with the rest of the class. (a) You spill a solid powder. Some ways to present your rules are as a (b) You spill a liquid. rhyme, song, rap or role play. (c) You break some glassware. (c) Swap your list with another pair and (d) Your experiment is fi nished. evaluate their rules. 9 001_HQSP8_SI.indd1_HQSP8_SI.indd 9 112/5/062/5/06 33:48:33:48:33 PPMM 3. Why is it important that you let your teacher know if there has been an accident or breakage in the science laboratory? 4. Some chemical bottles have warning labels on them. So do some household substances. At home try to fi nd some of these warning labels and sketch what they look like, or design your own warning label for the following: (a) a poisonous substance (b) a fl ammable substance (c) a corrosive substance. Figure 1.8 How many pieces of science 5. Name the item(s) of science equipment that equipment can you fi nd? can be used to: (a) mix large amounts of liquids together 8. Why should you never point the mouth of a (b) heat small amounts of liquid test-tube towards yourself or others when (c) measure small volumes of liquid heating it? (d) hold test-tubes 9. Describe one piece of science equipment as carefully and accurately as you can without (e) support equipment naming it. See if your partner can identify it. (f) heat small amounts of solids. 10. Write your own ‘dangerous laboratory There are two different fl ames on the Bunsen 6. drama’. Perform your play and ask the other burner. Draw them both and explain when students to list any dangers shown in your you would use each one. play. Watch the dramas by other students 7. Can you fi nd the ten pieces of science and make a list of their dangers. equipment in the puzzle in fi gure 1.8? Draw 11. Create a multimedia presentation or movie each piece separately into your book and to explain how different pieces of science label it. equipment can be used in a laboratory. 11.3.3 Microscopes and magnification There are many things in our environment that we cannot see without help. We use telescopes to help us see things that are far away such as the planets and details of the surface of the Moon.