Laboratory Safety Rules PDF

# 1.3 Safety in the Laboratory ## Flipped Classroom Watch a video and answer the questions. ## A Knowing Your School Laboratory A laboratory has many types of equipment. Figure 1.11 shows some of them. They provide us with water, electricity, and gas. * **Sink** * **Water tap** * **Electric soc...

# 1.3 Safety in the Laboratory ## Flipped Classroom Watch a video and answer the questions. ## A Knowing Your School Laboratory A laboratory has many types of equipment. Figure 1.11 shows some of them. They provide us with water, electricity, and gas. * **Sink** * **Water tap** * **Electric socket** * **Gas tap** **Figure 1.11 Some equipment in the laboratory** To ensure safety when we do experiments, there is **safety equipment** in the laboratory. Let us learn about some items on the next page. **Glossary** * Laboratory: 實驗室 * Equipment: 設備 * Electric socket: 電插座 * Gas tap: 煤氣掣 * Safety equipment: 安全設備 ## **Key Point** Safety equipment in the laboratory ### 1 Personal protective equipment * **Safety spectacles** * **Gloves** * **Laboratory coat** ### 2 Fire-fighting equipment * **Fire extinguisher** * **Sand bucket** * **Fire blanket** ### 3 Others * **First aid box** * **Eye wash bottle** * **Fume cupboard** ## **Key Point** A laboratory is a suitable place for doing experiments. **Glossary** * Safety spectacles: 安全眼鏡 * Fire extinguisher: 滅火筒 * Sand bucket: 滅火沙桶 * Fire blanket: 滅火氈 * First aid box: 急救箱 * Eye wash bottle: 洗眼瓶 * Fume cupboard: 通風櫥 ## B Laboratory Safety Rules Doing experiments in the laboratory is exciting, but it can also be dangerous. Accidents can occur if we are not careful. Let us learn about some potential dangers in the laboratory in Activity 1.6. ## **Activity 1.6** Potential Dangers in the Laboratory Identify the potential dangers in the laboratory shown below. Circle the potential dangers. Discuss with your classmates what the dangers are, and suggest what we can do to avoid these dangers. **Glossary:** * Potential danger: 潛在危險 ## **Key Point** To avoid accidents in the laboratory, we must follow laboratory safety rules. Below are some general safety rules. ## General Safety Rules ### **DOS** 1. Strictly follow your teacher's instructions. 2. Keep all exits and passages clear. 3. Keep the laboratory clean and tidy. 4. Wear safety spectacles when heating or mixing substances. 5. Tie up long hair and fasten school ties when doing experiments to prevent them from catching fire or dipping into chemicals. 6. Wash your hands thoroughly after doing experiments. 7. Report all accidents to your teacher at once. ### **DON'TS** 1. Do not enter the laboratory or do experiments without your teacher's permission. 2. Do not eat, drink, run or play in the laboratory. 3. Do not leave experimental set-ups unattended. 4. Do not point a test tube towards anyone when heating it. 5. Do not touch hot objects with bare hands. 6. Do not touch electric plugs with wet hands. 7. Do not smell or taste any chemicals unless instructed by your teacher. ## **Key Point** We must follow laboratory safety rules to prevent accidents in the laboratory. **Glossary:** * Laboratory safety rule: 實驗室 güvenlik kuralları * Electric plug: 電插頭 ## C Hazard Warning Symbols Look at Figure 1.12. There is a hazard warning symbol on the bottle of cleaner. The symbol warns us of the potential dangers of the cleaner. When we use or store the cleaner, we need to take safety precautions. **Figure 1.12 Hazard warning symbol on a bottle of cleaner** There are many different kinds of chemicals in the laboratory. Some of them are dangerous. Their cantainers also have hazard warning symbols (Figure 1.13). We should pay attention to these symbols and handle the chemicals with great care. **Figure 1.13 Chemical container with hazard warning symbol** Below are some hazard warning symbols and safety precautions to follow. | Hazard warning symbol | Safety precaution | |---|---| | FLAMMABLE易燃 | Keep away from flames and sparks. Keep flammable and oxidizing chemicals away from one another. | | OXIDIZING助燃 | Keep away from flames and sparks. Keep flammable and oxidizing chemicals away from one another. | | CORROSIVE腐蝕性 | Wear safety spectacles and protective gloves Keep the room well-ventilated. | | IRRITANT刺激性 | Wear safety spectacles and protective gloves. Keep the room well-ventilated. | | HARMFUL有害 | Wear safety spectacles and protective gloves. Keep the room well-ventilated. | | TOXIC有毒 | Carry out experiments in a fume cupboard if the chemicals give out toxic or irritating gases. | ## **Key Point** When we handle chemicals in the laboratory, we must read the hazard warning symbols on their containers and take safety precautions. **Glossary:** * Hazard marking symbol: 危險警告標記 * Safety precaution: 安全措施 * Chemical: 化學品 * Well-ventilated: 通風的 * Irritating: 刺激性 ## D 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: * **Laboratory accident:** * **Cuts** * **Heat burns** * **Splash of chemicals on skin** * **Splash of chemicals into eyes** * **Emergency action:** * **Clean and dress the cut.** * **Wash the affected area under slow-running water.** * **Wash the eyes with distilled water from an eye wash bottle.** ## **Key Point** When there is an accident in the laboratory, we must keep calm, report it to the teacher at once, and take emergency actions. ## **Quick Check** 1. The photo shows the hazard warning symbol on a correction pen. The liquid in this correction pen is: * **A corrosive.** * **B harmful.** * **C toxic.** * **D flammable.** 2. Betty breaks a glass apparatus when she is doing an experiment. She should: * **A report the case to the teacher at once.** * **B take the broken pieces of glass to the teacher.** * **C clean up the broken pieces of glass herself.** * **D ask her classmates to tell the teacher and continue her experiment.** ## E Handling Fire in the 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. **Figure 1.14 Flame goes out when the wax is used up** ### 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 (Figure 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** (Figure 1.15). **Figure 1.15 The fire triangle** **Glossary:** * Necessary condition: 必需條件 * Fuel: 燃料 * High temperature: 高温 * Oxygen: 氧 * Fire triangle: 火三角 ## **Practical 1.1 Studying Some Necessary Conditions for a Fire to Occur (Teacher Demonstration)** ### Aim To study some necessary conditions for a fire to occur. ### Apparatus and Materials per Class * **Power supply:** 1 * **Connecting wire:** 2 * **Insulating mat:** 1 * **Coiled nichrome wire (20 cm):** 1 * **White tile:** 1 * **Gas jar:** 1 * **Candle:** 2 * **Gas lighter:** 1 **Wear safety spectacles!** ### Part I High Temperature 1. Your teacher will prepare the set-up as shown in the photo on the left. 2. Turn on the power supply and slowly increase its voltage output until the coiled nichrome wire becomes red-hot. 3. Your teacher will put the wick of a candle onto the nichrome wire. * **a What happens to the candle?** **The candle lights up.** * **b What does the observation in a suggest?** **This suggests that high temperature is needed for a fire to occur (a condition of the fire triangle).** ### Part II 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 goes out.** * **b Suggest a reason for the observation in a.** **Oxygen (a condition of the fire triangle), which is needed for a fire to occur, is removed.** **Glossary:** * Nichrome wire: 鎳鉻線 * Voltage: 電壓 ## **Key Point** In our daily lives, the concept of the fire triangle is often applied. Below is an example. * **1 To start a fire in a barbecue, we put charcoal (fuel) into the barbecue pit. Then we may use some lighted paper to provide a high temperature for the charcoal to start burning.** * **2 We can make the charcoal burn more brightly by fanning because fanning removes the ashes and exposes the burning charcoal to the air (containing oxygen)**. For a fire to occur, a **fuel**, a **high temperature** and **oxygen** are needed. These three conditions form the **fire triangle** ## 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**. ## **Activity 1.7** Different Methods of Putting Out a Fire The table below shows some methods that we use to put out a fire. Complete it to show which condition in the fire triangle is removed in each case. | Method of putting out a fire | | | |---|---|---| | **1 Turn off a gas stove** | **Fuel** | | | **2 Cover the flame of a burner with a metal lid** | | **Oxygen** | | **3 Spray water onto a barbecue fire** | | **High temperature/Oxygen** | **Glossary:** * Thermal energy: 熱能 ## **Key Point** After-class activity Watch videos about the proper ways of using fire extinguishers, fire blankets and sand buckets on the internet. We learnt that there are several kinds of fire-fighting equipment in the laboratory (p. 29). If a small fire breaks out in the laboratory, the teacher may use this equipment to put out the fire (Figure 1.16). Can you point out which condition(s) in the fire triangle is/are removed in each method? * **1 Using a fire extinguisher:** **Oxygen** * **2 Using a sand bucket:** **Oxygen** * **3 Using a fire blanket:** **Oxygen** **Figure 1.16 Methods of putting out a fire in the laboratory. (DO NOT use the fire-fighting equipment by yourself!) ** ## **Key Point** We can put out a fire by removing any one of the conditions in the fire triangle. ## **Quick Check** 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** **This puts out the fire by removing the high temperature and oxygen from the fire triangle.** * **2 Hit the fire with a fire beater.** **This puts out the fire by removing the oxygen from the fire triangle.** * **3 Clear a strip of plants to make a fire break** **This prevents a fire from spreading by removing the fuel from the fire triangle.** **Glossary:** * Fire beater: 山火拍 * Fire break: 防火帶 ## **Section Summary 1.3** 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. 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.** 5. We can put out a fire by removing any one of the conditions in the fire triangle. ## **Section Exercise 1.3** ### Level 1 **Questions 1 to 3: Fill in the blanks.** 1. We must follow **laboratory safety** to prevent accidents in the laboratory. p. 31 2. Fire extinguishers, fire blankets and **sand buckets** are different types of fire-fighting equipment commonly found in the laboratory. p. 29 3. For a fire to occur, **oxygen**, a **fuel** and a **high temperature** are needed. These three conditions form the **fire triangle.** p. 34 ### Level 2 **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) * **b Give ONE safety precaution that you should take when using this bleach.** (1 mark) * **c Suggest what you should do if a small amount of bleach accidentally splashes onto your skin.** (1 mark)