Science Form 4 - Safety Measures in the Laboratory - PDF

# **SCIENCE FORM 4** ## **DUAL LANGUAGE PROGRAMME** ### **THEME 1: SCIENTIFIC METHODOLOGY** #### **Chapter 1: Safety Measures in the Laboratory** **Keywords** - Face mask - Gloves - Fume chamber - Biological waste substances - Mercury poisoning - Types of fire extinguishers **What you will lea...

# **SCIENCE FORM 4** ## **DUAL LANGUAGE PROGRAMME** ### **THEME 1: SCIENTIFIC METHODOLOGY** #### **Chapter 1: Safety Measures in the Laboratory** **Keywords** - Face mask - Gloves - Fume chamber - Biological waste substances - Mercury poisoning - Types of fire extinguishers **What you will learn about:** - Personal protective equipment - Disposal of waste - Fire extinguishers **What are the examples of personal protective equipment and their functions?** **What are the characteristics of substances that cannot be disposed into sinks? ** **How should biological waste substances be managed?** **How should accidents in the laboratory be handled?** **How many types of fire extinguishers are there?** **Science Digest** **Mercury Spill in School Laboratory** On Wednesday, 2 May 2018, a total of 21 students and a teacher were quarantined for about 20 minutes due to a mercury spill from a broken thermometer at a secondary school. The incident occurred at 2.20 p.m., when the students conducted an experiment in the science lab. A team of 10 firefighters was rushed to the scene after receiving an emergency call at 2.24 p.m. The firefighters responded quickly to quarantine the area, before the disinfection process took place. The disinfection work at the scene was completed at 3.30 p.m. **Source:** myMetro ### **1.1 Personal Protective Equipment** You learned about safety rules and measures in the laboratory in Form 1. In order to keep you safe in the lab, there is a variety of protective equipment that you need to know and use correctly. **Personal Protective Equipment on a Student and their Functions** Personal protective equipment is needed to protect the wearer from danger. - **Goggles** Protect the eyes from hazardous chemical substances such as acid, bromine, ammonia, and reactive metals. - **Face mask** Protects the nose and mouth from inhaling pungent and volatile chemical substances and dust. - **Gloves** Gloves made of rubber protect the hands from hazardous chemical substances. - **Lab coat** A lab coat is made up of safety layers and is easily removed if there is an emergency. The lab coat is important to protect clothing from damage. - **Closed shoes/safety shoes** Closed shoes must be worn in the laboratory. Their function is to protect the feet from chemical substance spills and glass splinters. **Photograph 1.1 Personal protective equipment on a student** **Personal Protective Equipment in the Laboratory** Personal protective equipment that is available in the laboratory includes the safety shower, eyewash station, fume chamber, and laminar flow cabinet. Even though there is personal protective equipment in the laboratory, every accident or injury in the laboratory must be reported immediately to the teacher. - **Laminar flow cabinet** This cabinet is used to avoid contamination when microbiological activities are carried out. - **Safety shower** The safety shower is used to immediately clean and rinse parts of the body or clothing that have come into contact with chemical substances. - **Fume chamber** The fume chamber is used to carry out experiments that use substances which are volatile, flammable, poisonous, corrosive or pungent. - **Eyewash station** The eyewash station is used to immediately rinse and wash the eye that has come into contact with chemical substances. **Photograph 1.2 Personal protective equipment in the laboratory** ### **1.2 Disposal of Waste** **Waste that Can be Disposed of into Sinks and Waste that Cannot be Disposed of into Sinks ** After you have carried out an experiment, how should you manage the waste from the experiment? Can all waste substances be disposed of into sinks? **Photograph 1.3 Examples of waste substances from the laboratory** Waste substances can be divided into two types: - Substances that can be disposed of into sinks - Substances that cannot be disposed of into sinks Substances that can be disposed of into sinks are substances that have low concentration and are non-hazardous such as neutral substances, weak acids and weak alkalis. **Examples of substances that cannot be disposed of into sinks are:** - Solid waste - Substances with pH value lower than 5 and more than 9 - Organic solvent compounds -Chemical substances (acid, grease, oil, oil paint, hydrogen peroxide) - Toxic substances - Heavy metals - Organic waste substances (microbes, carcasses) - Radioactive waste - Volatile substances - Reactive substances These substances can pollute the environment and are hazardous to living things. ### **Activity 1.1** **Aim:** To search for the effects of disposing substances that cannot be disposed of into the sink. **Instructions:** 1. Carry out this activity in groups. 2. Find the effects of disposing the following substances into the sink: - Solid waste - Substances with pH less than 5 and more than 9 - Grease and oil - Heavy metals - Organic waste (such as animal carcass). 3. Use various resources such as the Internet and the library to obtain relevant information. 4. Present the results of your discussion in class ### **Managing Biological Waste Substances** What are you disposing? Not all biological waste substances can be disposed of into the sink or dustbin in the laboratory. Biological waste substances are managed by using Standard Operating Procedure (SOP). Let us look at the types of biological waste substances and the SOP to manage them. **Science Gallery** Biological waste substances include disposed biological substances that can cause serious harm or biological hazards. These biological waste substances include waste materials, tissue, carcasses, culture medium, plastic containers, glass and gloves. **Really, teacher? What is the proper way to manage biological waste substances?** The Standard Operating Procedure (SOP) for the disposal of biological waste products is the procedure that is used for the purpose of managing biological waste substances in a laboratory. **Table 1.1 Standard Operating Procedures for disposal of biological waste substances** | Waste substance category | Category A | Category B | Category C | Category D | |---|:---:|:---:|:---:|:---:| | Type of biological waste substance | Sharp equipment | Non-sharp solids | Carcasses/organs | Liquid | | Examples | Syringe, needle, scalpel blade | Gloves, culture medium | Lab animals, experimental animals | Blood, serum | | Biological waste management | Placed in special containers (sharps waste bins). Container is stored in a safe place before disposal | Packaged and placed in biohazard plastic bags. Autoclaved and placed into biohazard bins | Wrapped in absorbent material (tissue paper), packaged well in a biohazard plastic bag and frozen before disposal | Decontaminated by autoclave. Disposed of directly into a sewage system through the sink or toilet | **Waste substance category:** - Category A - Temporarily stored in a safe place. - Category B - Placed in a leak-proof autoclave bag and autoclaved (temperature 121°C, pressure 15 psi, 20 minutes). - Category C - Packaged carefully and temporarily stored in a freezer. **Waste that has been decontaminated is placed into a biohazard bag.** **Waste that has been packaged is labelled and placed in biohazard bins. Biohazard bins are temporarily stored in a safe, controlled condition and cooled before centralised disposal is carried out. ** **Figure 1.1 Flow chart of Standard Operating Procedure for disposal of biological waste substances ** **Source:** Laboratory Management, Department of Chemistry, Faculty of Science, UTM ### **Activity 1.2** **Aim:** To create a multimedia presentation about new ideas to manage biological waste substances in the future. **Instructions:** 1. Carry out this activity in groups. 2. Discuss new ideas on how to manage biological waste substances that cannot be accommodated by Earth in the future, such as inventing disposal equipment or future incinerators. 3. Present the results of your group discussion in the form of a multimedia presentation. ### **1.3 Fire Extinguishers** **Types of Fire Extinguishers** A fire extinguisher is a device that is used to control or extinguish fire. There are four types of fire extinguishers that are commonly used. Fire extinguishers are classified based on their medium. The types of fire extinguishers that are commonly used are shown in Figure 1.2 below. **Types of Fire Extinguishers** | **Type of Fire Extinguisher** | **Label Colour** | **Extinguishes** | |---|---|---| | **Water** | Red | Flammable solids such as cloth, paper and wood | | **Foam** | Cream | Flammable solids such as wood and paper, as well as types of liquid or gas that are flammable such as oil, paint and natural gas. | | **Carbon dioxide** | Black | Fires that involve electrical appliances, gas and vapour. | | **Dry powder** | Blue | All types of fires | **Figure 1.2 Types of fire extinguishers** Fires can be divided into a few types based on the substance that burns. Fire extinguishers are used based on the potential sources of fire that are identified in a building or area. Table 1.2 shows the types of fires and the fire extinguishers that are suitable to be used. **Table 1.2 Types of fires and fire extinguishers that are suitable for use** | **Type of Fire** | **Explanation** | **Type of fire extinguisher** | |---|---|---| | **Class A** | Fires that involve flammable solids (except metals) such as wood, paper, cloth and any flammable material | Water, Foam, Dry powder | | **Class B** | Fires that involve liquids such as petrol, kerosene, diesel, paint, and varnish | Foam, Dry powder, Carbon dioxide | | **Class C** | Fires that involve gases such as LPG, LNG, and oxygen | Dry powder, Carbon dioxide | | **Class D** | Fires that involve metals such as magnesium, aluminium, sodium, and potassium | Dry powder | | **Class E** | Fires that involve electrical appliances | Dry powder, Carbon dioxide | | **Class F** | Fires that involve fats and oils | Dry powder, Carbon dioxide | **Other fire extinguishers that are used include the ABC fire extinguisher, fire blanket, sand and water. Sand can be used to extinguish early stage fire. Water can be used to extinguish fire except fire resulting from oil.** **Fire blanket** - Made of two layers of glass fibres - Able to extinguish small or moderate fires that are difficult to extinguish with water - Extinguishes fire on the victim when it is wrapped around him **ABC fire extinguisher** - Can be used for all types of fires except fire that results from metals and gases that will not allow explosion - Not harmful to human and animal - Does not pollute the soil - Easy to maintain (at least once a year) - Moisture produced lasts longer, thus preventing fire from spreading again **Photograph 1.4 ABC fire extinguisher ** **Photograph 1.5 Fire Blanket** ### **How to Use a Fire Extinguisher** Fire extinguishers are very easy to use. Nevertheless, we need to learn the correct way of using a fire extinguisher. **Simple fire safety checklist:** - Install smoke detectors - Ensure that there is an emergency plan and an emergency route from each room. All the occupants should be aware and also trained to use it - Use light bulbs with suitable wattage - Store electrical appliances that produce heat at least one metre away from curtains, furniture and other flammable equipment - Avoid charging electronic equipment on the bed - Check electrical wiring from time to time to identify any damages in order to prevent fire resulting from short circuits. - Avoid making unauthorised extensions or overloading electrical circuits - Place matches and lighters out of the reach of children - Store containers filled with flammable liquid far from fire sources and children - Keep one dry powder or ABC-type fire extinguisher at your home **1. Remove the safety pin from the fire extinguisher. Ensure that the fire extinguisher is positioned upright.** **2. Aim the nozzle of the fire extinguisher at the base of the fire. Ensure that you are at a distance of around 2.0-2.5 meters from the fire.** **3. Squeeze the handle on the top of the fire extinguisher.** **4. Spray evenly on the entire fire source by sweeping the nozzle from side to side.** ### **Activity 1.3** **Aim:** To demonstrate how to use a fire extinguisher. **Instructions:** 1. Carry out this activity in groups. Each group consists of four members. 2. Choose a member who will play the role of a firefighter. 3. The student who plays the firefighter is given 5 minutes to read the instructions on how to use the fire extinguisher. The student can look up the information from the Internet, research or ask the laboratory assistant or teacher. 4. After 5 minutes, the student must play the role of a firefighter using the fire extinguisher. Observe the demonstration. 5. Choose another group member to be the firefighter and role-play until every member has successfully used the fire extinguisher. ### **Carrying Out an Audit on Fire Extinguishers at School** Usually, a few fire extinguishers are available and placed around the school. However, can the fire extinguishers in your school function well if there is a fire? How would you carry out an audit on the fire extinguishers at your school? ### **Activity 1.4** **Aim:** To carry out an audit on fire extinguishers at school. **Instructions:** 1. Carry out this activity in groups. Each group should consist of four members. 2. Collect information about the fire extinguishers in the school compound. 3. Record: - The types of fire extinguishers - Expiry date of fire extinguishers - Pressure reading on the fire extinguishers - The number of fire extinguishers based on types - The location of fire extinguishers in the school’s emergency route plan 4. Pass your respective records in a clockwise direction. The other members must correct your record if there is any error. 5. After 30 minutes, return to the laboratory and present your findings. ### **Creating a simple Fire Extinguisher** **Activity 1.5** The kitchen has a variety of flammable substances such as flour, sugar, and oil. The existence of fuel can also be a source of fire at home. Based on the problem statement above, create a simple fire extinguisher that works by using materials available at home. The following are the basic steps of the STEM activity that must be carried out by students: 1. Raise questions and identify the problems 2. Develop and use a model 3. Plan and carry out an investigation in the form of inquiry 4. Analyse and interpret the obtained data 5. Use mathematical thinking and computational thinking 6. Create explanations and design solutions 7. Involve in debates and discussions based on evidence 8. Obtain information, then evaluate and communicate the information ### **FORMATIVE PRACTICE 1.3** 1. State four types of fire extinguishers. 2. What is the function of a fire blanket? Explain how it can save victims of small fires. 3. Arrange the correct sequence in using a fire extinguisher. ### **Summative Practice 1** 1. (a) Give three examples of personal protective equipment that can be found in your school laboratory. - Laminar flow cabinet - Fume chamber - Safety shower - Eyewash station (b) Why is the school laboratory regarded as a restricted area? (c) Jasman disposed of lemon juice, the waste from a science activity, into the sink. Justify Jasman’s action. ### **Mind Challenge** 3. When you enter the laboratory, do you always have to wear a face mask? Explain your answer. 4. Haziq received a task to carry out an experiment to determine the boiling point of salt water. Explain how Haziq can ensure that all the safety measures in the laboratory are observed while he is carrying out the experiment. 5. Explain the correct steps to disposed of sharp objects that have been used in experiments in the science laboratory. ### **Summary** - **Personal Protective Equipment** - Goggles - Gloves - Lab coat - Lab shoes - Face mask - **Disposal of Waste** - Substances that can be disposed of into the sink - Substances that cannot be disposed of into the sink. - **Fire Extinguishers** - Types of fire extinguishers - Using a fire extinguisher - **Managing Biological Waste Substances** - **Auditing Fire Extinguishers** - **Steps to Handle Accidents in the Laboratory** - **Creating a Simple Fire Extinguisher** ### **Self-Reflection** After studying this chapter, you are able to: - **Personal Protective Equipment** - Explain and give examples of personal protective equipment and their functions. - **Disposal of Waste** - Explain with examples of substances that can be disposed of into the sink. - Characterise substances that cannot be disposed of into the sink. - Manage biological waste substances. - Communicate steps to handle accidents in the laboratory. - **Fire Extinguishers** - Identify the types of fire extinguishers. - Explain how to use a fire extinguisher. - Carry out an audit on fire extinguishers at school. - Create a simple fire extinguisher. ### **Figure 1: Fire in the Science Laboratory** - Ethanol is too close to the Bunsen burner/fire. - The type of fire is Class B. - The suitable fire extinguisher to stop the fire: Foam, Dry powder, Carbon dioxide. **In your opinion, why did the fire occur?** Ethanol is a flammable and volatile substance. It is likely that Azhar did not follow proper safety procedures. He did not have a good understanding of safety measures. **What should Azhar do to extinguish the fire?** 1. Azhar should immediately turn off the gas supply to the Bunsen burner. 2. Azhar should use a fire blanket to cover the fire and suffocate it. If a fire blanket is not readily available, he could use a damp cloth or towel. 3. If the flames are small, Azhar could use a fire extinguisher. 4. If the fire cannot be extinguished, Azhar should call the fire department. **As a precautionary step, fire extinguisher audits should always be carried out. State five things that should be observed when the audit is being carried out in your school.** 1. **Expiry date** - Ensure that all fire extinguishers are not expired. 2. **Pressure gauge** - Ensure that the pressure gauge on each fire extinguisher is in the green zone, meaning it is fully charged. 3. **Type of fire extinguisher** - Ensure that the type of fire extinguisher is appropriate for the type of fire hazard present in each area. 4. **Location** - Ensure that fire extinguishers are located in easily accessible places. 5. **Maintenance** - Ensure that fire extinguishers are regularly inspected and maintained.