Hilary Sci 1.3 Laboratory Safety Rules PDF

Safety In the laboratory To avoid accidents in the laboratory, we must follow laboratory safety rules”. Below are some general safety rules. General safety rules Et nn...

Safety In the laboratory To avoid accidents in the laboratory, we must follow laboratory safety rules”. Below are some general safety rules. General safety rules Et nn sedi 1 ~ Strictly follow your teacher’s instructions. Do not enter the laboratory or do Lo experiments without your teacher's permission. [2 Keep all exits and passages clear. Do not eat, drink, run or play in the laboratory. | 3 Keep the laboratory clean and tidy. Do not leave experimental set-ups unattended. 4 Wear safety Do not point a spectacles when test tube towards | : heating or mixing anyone when substances. heating it. 5 Tie up long hair Do not touch hot and fasten school objects with bare ties when doing hands. experiments to prevent them from catching fire or dipping into chemicals. 6 Wash your hands thoroughly after doing Do not touch electric plugs™ with wet experiments. hands. 7 Report all accidents to your teacher at once. Do not smell or taste any chemicals unless instructed by your teacher. v 2 ES Rad : EAE S 3 3 (43 Fa = 1 1:4 p35) R hot v 5 Cea 0 y A ERM et Sg TA a. Ve Ct SL WARES Wen us tf ollaty Iaboratory safety rule ¥ iy a kin La laboratory safety rule BBRZEZ25FAl electric plug Bil x WW po! 1% Safety in the laboratory (® Handling common laboratory accidents Accidents are less likely to occur if we follow laboratory safety rules and handle chemicals carefully. But if accidents do occur, we must keep calm. We should report it to the teacher at once and follow his/ her instructions to take emergency actions. Below are some common laboratory accidents and the emergency actions needed. Pg ey TD Sun TNA TS, EOTTIRTT SIR A —— Sr Et ICE LA ER TA AC ST TT = 4 te] 3 Cad GA ) g Heat burns a eo Splash or ~ O Splash of chemicals chemicals onn skin into eyes GER dL Ty AN Laboratory accident Wash the eyes with distilled water from an eye wash bottle. Emergency action vi § Re a ee ARE 8 ek Sak te an acceident iin the laboratory, we must keep cals iL once>and takece emergency actions. J 33  R ss E l si en on E — i — 1 The photo shows the hazard 2 Betty breaks a glass apparatus when she is warning symbol on a doing an experiment. She should correction pen. A report the case to the teacher at once. The liquid in this B take the broken pieces of glass to the correction pen is teacher. C clean up the broken pieces of glass A corrosive. herself. B harmful. D ask her classmates to tell the teacher and C toxic. r continue her experiment. D flammable. Check your answers (p: £3) E Handling fire in laboratory If a fire accident occurs in the laboratory, keep calm and report it to the teacher at once. The teacher can help put out the fire in a proper way. To understand methods of putting out a fire, we need to know the necessary conditions” for a fire to occur. 1 Necessary conditions for a fire to occur You should have noticed that the flame of a candle goes out when the wax is used up (Fig 1.14). This tells us that a fuel” is needed for a fire to occur. Besides a fuel, a high temperature” and oxygen” are also needed for a fire to occur. These three conditions (fuel, high temperature and oxygen) form the fire triangle” (Fig 1.15). Fig 1.14 Flame goes out when the wax is used up RE Nr PR LR LE Ll LP EE EE EE ET PPE PRET EE RTL LLL EE EE ELA necessary condition 4% 1514 fuel #4%} high temperature =)8 oxygen & fire triangle X =f “ Kw po ind, Part Il Oxygen 1 Your teacher will put a burning candle on a white tile. 2 Cover the burning candle with an inverted gas jar. a What happens to the candle flame? The candle flame | A MA b Suggest a reason for the servation in a. (a condition of the fire white tile — QUA triangle), whith isi needed for a fire to occur, is removed. In our daily lives, the concept of the fire triangle is often applied. Below is an example. @ To start a fire in a barbecue, @ We can make the charcoal we put charcoal (fuel) into the burn more brightly by fanning barbecue pit. Then we may use because fanning removes the some lighted paper to provide ashes and exposes the burning a high temperature for the charcoal to the air (containing charcoal to start burning. oxygen). : faa El } : EE Ts via ye eras W Akad ; Pe PA bc {5i Cfe &:. =_al re:needed. These three conditions form the i.) A ;fire triangle. NRE LN a bd RE Teele ~ V\  Safety in the laboratory “ Did you know?.( } Fireproof balloon Look at the photo. The balloon does not catch fire and burst when it touches the flame! Why? The balloon has some water inside it. The water absorbs the thermal energy® given out by the flame. The balloon is kept below the temperature required for a fire to occur. 2 Methods of putting out a fire We learnt that a fuel, a high temperature and oxygen are needed for a fire to occur. If any one of these conditions in the fire triangle is removed, the fire will go out. We use this principle to develop methods of putting out a fire. Let us learn about this in Activity 1.7. 4 A ctivity 1.7 Different methods of putting out a fire The tabl e belo w show s some met hod s that we use to put out a fire. Com ple te it to sho w which condition in the fire triangle is removed in each case. Method of @ Turn off a gas @ Cover the flame of a | @ Spray water onto putting out a burner with a metal a barbecue fire. fire Condition(s) in the fire triangle removed thermal energy ZA8E 57 FAW pon We learnt that there are several kinds of fire-fighting equipment in Waich videos the laboratory (p. 29). If a small fire breaks out in the laboratory, the about the proper teacher may use this equipment to put out the fire (Fig 1.16). Can you ways of using fire extinguishers, 1ire point out which condition(s) in the fire triangle is/are removed in blankets and sand each method? Said @ Using a fire ® Using a sand © Using a fire XRg TY bucket blanket hkedcity fire safety / / J / / i ? \ ~~ / \ / | rH 4 7 ‘ 4 7) v 4 A ' ‘ - ’] Y 1 A and fire fighting |X % NG | [ - vi { ; ‘ Pom [| -. | equipment \ / / ~ / \ 4 < ’ ILf % A ). ) Fig 1.16 Methods of putting out a fire in the— (DO NOT use the fire-fighting equipment by yourself!) ———————— St Ey # § Ap _ ¥ waa Ed. gat 3 a La F ih JE “ww Nw» DL Lo oe tT SE } # Re li SF Ba A a Er T Key point We can put out a fire by removing any one of the conditions in the fire triangle. : 3 ane RE aa MA hn ta i * 3 ater er Vi SERS A 4 I a i I a a M1 Below are some methods of putting out a fire or preventing a fire from spreading. Complete the sentences to explain how each method works. 1 Spray water on the fire 2 Hit the fire with a fire 3 Clear a strip of plants to beater” make a fire break” This puts out the fire by This puts out the fire by This prevents a fire from removing the Sd the Sprasding by removing the Ii Ih ARVANA png & yon LyLLL [ (WL from the fire triangle. from oea ‘e triangle. a the fire triangle. Check your answers (p. 78) 38 fire beater IWF fire break ByA#  Safety in the laboratory @¥Sectionfsummaryrlss 1 We must follow laboratory safety rules to prevent accidents in the laboratory. 2 When we handle chemicals in the laboratory, we must read the hazard warning symbols on their containers and take safety precautions. Some common hazard warning symbols: \ 4 4 3 When there is an accident in the laboratory, we must keep calm, report it to the teacher at once and take emergency actions. 4 For a fire to occur, a fuel, a high temperature and oxygen are needed. These three conditions form the fire triangle. «cccccceeeeceeevcccccncnen.. 5 We can put out a fire by removing any one of the conditions in the fire triangle. iSectionlexerciseRlss, IETED Questions 1 to 3: Fill in the blanks. 1 Wemust follow | 4 jh 04Y WAAR to prevent accidents in the laboratory. « p. 31 } i [ \ \ ron /.. J 2 Fire extinguishers, fire blankets and _ Jnr )| 1x AL { J tare different types of fire-fighting equipment commonly found in the laboratory. &p.29 17 are needed. These three nN - conditions form the + |Y? i RRA es &p. 34 4 The photo on the right shows the hazard warning symbol on a bottle of bleach. a State the meaning of the hazard warning symbol shown. (1 mark) &p. 32 b Give ONE safety precaution that you should take when using this bleach. (1 mark) &p. 32 ¢ Suggest what you should do if a small amount of bleach accidentally splashes onto your skin. (1 mark) & p. 33 39