School Science Lessons
2024-08-30
(topic03)
Chemical safety
Contents
3.1.0 Chemicals Not permitted in schools, Australia
3.2.0 Duties of a teacher
3.3.0 Chemical residues
3.4.0 Chemicals safety
3.5.0 Chemical hazards
3.6.0 Safety items
3.9.8 Scheduling
3.7.0 Storing chemicals
3.8.0 Workplace Health and Safety
3.2.0 Duties of a teacher
Teachers should select school science lessons and laboratory experiences that are appropriate to the student group and the level of learning.
When selecting laboratory experiences the teacher must check that school authorities approve the activity.
This document contains suggestions for practical teaching by a trained science teacher.
After choosing an experiment, the teacher should practise it in the preparation room before demonstrating it to students or before requiring students to do it.
The teacher has the duty of making the decision about whether the experiment is safe for the children in the classroom or laboratory.
The level of risk of injury to students and teacher will vary from school to school, depending on:
1. expertise of the teacher,
2. size of the student group,
3. diversity of students, and
4. the facilities and equipment.
3.2.1 Experimental procedures
3.2.2 Protective clothing and equipment
3.2.3 Supervision of students
3.2.4 Teach manipulative skills
3.2.5 Teacher responsibility
3.3.0 Chemical residues
3.3.1 Copper residues
3.3.2 Hydrogen sulfide waste bottle
3.3.3 Lead residues
3.3.4 Mercury residues
3.3.5 Organic liquid residues
3.3.6 Silver residues
3.3.7 Zinc residues
3.4.0 Chemicals safety
3.4.1 Chemicals safety
3.4.2 Chemicals spill kit
3.4.3 Chemicals swallowed
3.4.4 Chemical vapours and smelling chemicals
3.4.5 Correct names of chemicals
3.4.6 Corrosive substances
3.4.7 Disposal of waste chemicals
3.4.8 Gas or vapour inhalation, EAR, CPR
3.4.9 Handling and transferring chemicals
3.4.10 Prepare dilute acids and bases. (Safety instructions)
3.4.11 Quantity of chemical to be used in experiments
3.4.12 Skin contamination
3.4.13 Tasting chemicals
3.6.0 Safety items
3.6.1 Carbon dioxide soda siphon bulbs, (Safety)
3.6.3 Eye washing, safety showers
3.6.4 Glass wool
3.6.5 Sharps safety
3.6.6 Test-tubes, microscope slides
3.7.0 Storing chemicals
3.7.1 Storing chemicals, rules
3.7.2 Storing acids, acetic acid
3.7.3 Storing alkalis, ammonia solution
3.7.4 Storing chromium (VI) oxide
3.7.5 Storing flammable liquids
3.7.5 Storing hygroscopic and deliquescent substances
3.7.7 Storing organic chemicals
3.7.8 Storing oxidizing agents
3.7.9 Storing sodium and potassium
3.7.10 Storing sodium chlorate and potassium chlorate
3.8.0 Workplace Health and Safety
3.8.1Workplace Health and Safety
3.8.2 Hazard classification and experiments
3.8.3 Laboratory organization
3.8.4 Risk assessment
3.2.1 Experimental procedures
1. Read the label on reagent bottles twice to avoid errors.
2. Always follow exactly the instructions for chemical experiments.
3. Do not substitute another chemical for chemicals specified in the experiment instructions.
4. Always add a solid to a liquid reagent to achieve better control of gases that form in the reaction.
5. Do not let students do unauthorized experiments.
Chemicals are safe by themselves, but they may form explosive mixtures when mixed with oxidizing agents, e.g. sulfur, sucrose, (cane sugar), and powdered zinc.
6. This document does not recommend the use of gas generators, e.g. Kipp's apparatus.
3.2.2 Protective clothing and equipment
1. Students in chemistry classes should wear strong shoes and take care of unbuttoned long sleeves and long hair.
Students must wear protective clothing, e.g. aprons, safety glasses and nitrile chemical-resistant gloves when chemicals are being handled.
Teachers should be aware of students who wear contact lenses.
2. Safety spectacles, | safety goggles
Students should wear safety spectacles or safety goggles if the experiment could propel chemicals into the eyes.
Students wearing prescription glasses should change to use safety glasses.
There is always the danger of hot or caustic materials being splashed into the eyes.
3. Safety gloves
Many schools require students to wear heavy gloves, safety spectacles or safety goggles, and closed shoes for all experiments.
The four kinds of gloves are as follows:
3.1 Disposable surgical gloves, which are used during dissections, handling animal tissue and blood products, but not for chemicals,
3.2 Rubber washing-up gloves, which are not designed to protect against concentrated chemicals or organic solvents, e.g. acetone,
3.3 Nitrile chemical-resistant gloves, which are designed for handling concentrated acids and organic solvents,
3.4 Insulated heat-proof gloves.
Safety gloves
Students must use safety glasses and nitrile chemical-resistant gloves if:
diluting concentrated acids or bases, (senior students only), and
when heating chemicals, to avoid the danger of hot or caustic materials being splashed into the eyes.
Students must wear insulated heat-proof gloves and aprons if the activity could result in damage to their hands or body.
Pay attention to unconfined long hair, jewellery, ties, unbuttoned long sleeves and loose clothing.
Synthetic garments that may be a fire hazard.
Students in chemistry classes should wear strong shoes that completely cover the feet and protect them from spilt corrosive or hot liquids.
Students may NOT wear sandals in the laboratory.
3.2.3 Supervision of students
Supervision of students must be continuous so that unauthorized or inappropriate behaviour does not lead to accidents resulting in physical injury or fires
Teachers must choose a set of laboratory rules to be prominently displayed and with copies given to students.
Students must know the rule and understand them.
Teachers must pay particular attention to the following rules:
1. Students do not enter any laboratory or storeroom unless a teacher is present.
2. Students do not eat or drink in the laboratory or storeroom.
3. Students do not taste chemicals.
4. Students must behave in a careful and businesslike manner.
5. Students are safely seated and not crowded, with fellow students, chemicals and glassware not within "elbow width".
3.2.4 Teach manipulative skills
Teachers should teach the necessary manipulative skills by demonstration before asking students to use the skills in an experiment.
These skills include heating chemicals in test-tubes, heating large volumes of liquids, handling glassware containing hot liquids, carrying glassware and reagent bottles.
Diluting concentrated acids, inserting glass tubing or thermometers in rubber stoppers, should be done by the teacher in the preparation room before an experiment.
3.2.5 Teacher responsibility
In accordance with the Department of Education Manual module HS-07: Occupational Health and Safety, teachers are responsible for the health and safety of students while on school premises and participating in official school activities, wherever these may take place.
Teachers should take care to ensure that appropriate use is made of all safeguards, safety devices, personal protective equipment and other appliances provided
for health and safety,
(a) maintain healthy and safe procedures and practices,
(b) collaborate with Regional Occupational Health and Safety Consultants, employees of Education Queensland, workplace health and safety representatives or workplace health and safety committees to assess hazards, which exist in the school or workplace, and to eliminate or reduce the associated risks as required,
(c) identify hazards and minimize risks in science teaching areas,
(d) ensure that employees, students and other users of educational facilities receive appropriate workplace health and safety information and training (see your School Health and Safety Officer or Principal),
(f) manage behaviour of students (including school ground and excursion activities),
(g) ensure all work injuries, work related illnesses and dangerous occurrences at the workplace are recorded.
Such records are to be completed and dispatched to the appropriate authorities within the designated period (see your Principal or Registrar),
(h) ensure special needs groups, e.g. people with disabilities and persons from non-English speaking backgrounds, are considered in regard to workplace health and safety issues.
3.3.1 Copper residues
Copper residues can be used to demonstrate recovery of the metal by displacement from solution by a more active metal, e.g. scrap iron or steel wool.
Precipitate insoluble copper or zinc sulfide by adding sodium sulfide solution, filter off the insoluble sulfide, dry and dispose of as solid waste.
Copper residues can be treated to recover copper sulfate by evaporation.
If disposal is intended, copper residues can be treated with iron to reduce copper ions to metallic copper.
Place copper residues in a large container and add sufficient steel wool to achieve discoloration of the blue solution.
Pour off the iron solution.
Wrap the solid reduced copper in newspaper and dispose in your solid waste bin.
Flush the iron solution with water to the sink or pour over the ground or school garden.
Recover iron salts by evaporation and later dispose in a solid waste bin.
3.3.2 Hydrogen sulfide waste bottle
Do not add acidified solutions to metal sulfides, because the reaction produces hydrogen sulfide gas.
If a rotten egg smell indicates production of hydrogen sulfide gas in a waste bottle, add solid sodium hydroxide until the solution pH >7 and leave in the fume cupboard with the lid off until no smell occurs.
3.3.3 Lead residues
Lead residues may contain metallic lead, solid lead salts and lead ions in solution.
Do not recycle lead in the school laboratory, but dispose them through a licensed waste contractor or government chemistry laboratory.
3.3.4 Mercury residues
If using liquid mercury in the laboratory keep a special mercury residues bottle.
Mercury residues must be kept well-sealed, especially if mercury metal is present.
Do not clean waste mercury in the school laboratory, but store for removal by a licensed waste contractor or government chemistry laboratory.
3.3.5 Organic liquid residues
Keep halogenated and non-halogenated organic liquid residues separate.
Use the bottles for immiscible liquids only.
Keep them away from ignition sources and store them in a fume cupboard for removal by a licensed waste contractor or government chemistry laboratory.
3.3.6 Silver residues
Add solid sodium chloride to silver residues precipitate the silver as silver chloride.
Decant the clear solution and wash down the sink.
Store the precipitate for recycling or waste collection or give it to a professional photographer.
To recover silver, add sodium carbonate to waste solutions to form a silver carbonate precipitate, then collect and dry the precipitate.
Heat the precipitate with carbon powder, or on a carbon block, to form metallic silver.
Most metals will displace silver metal from soluble silver salt solutions to form attractive silver crystals.
3.3.7 Zinc residues
Treat for recycling or dispose to garbage.
Precipitate insoluble zinc sulfide by adding sodium sulfide solution, filter off the insoluble sulfide, dry and dispose as solid waste.
3.4.1 Chemicals safety
If a demonstration requires any chemicals, there may be a risk of spilling hazardous materials.
1. Ensure that you are familiar with the relevant MSDS for the chemicals used or have discussed with the lecture demonstration technician the relevant safety issues involved with any chemical used.
2. Be sure to have a chemical spill kit available with the demonstration.
Use Spill kits as instructed.
3. Be sure all chemicals are in labelled containers with a lid.
4. Do NOT pour chemicals until the moment they are required for the demonstration.
5. Be sure all unwanted chemicals are disposed of in the proper fashion.
6. Do NOT pour used chemicals down the sink.
7. Wear safety goggles where there is the possibility of eye contact.
8. Use spill trays if spillage is likely.
Follow the following general precautions:
1. Chemicals should be treated with caution.
Do not allow chemicals to come in contact with skin or clothing.
Remove contaminated clothing and bag it.
2. Spillage on the skin: Immediately wash affected area with water for several minutes.
3. For chemicals in the eyes, wash the eyes with running water for at least 10 minutes.
Inform safety officer and seek medical treatment.
4. Always report any accidents to the safety officer who may recommend seeking medical advice.
3.4.2 Chemicals spill kit
After a spill, open windows and doors to improve cross ventilation, and immediately inform school authorities.
1. A school science laboratory spill kit could contain the following items:
Cardboard box, Disposable rubber gloves, Dustpan and bucket, Mop and bucket, Nitrite rubber gloves, Paper towel, Plastic bucket, 5L, Plastic scoop, Respirator, with P2 cartridge, Safety glasses and safety goggles, Sodium bicarbonate, sodium hydrogen carbonate, 2 kg Sodium carbonate, 2 kg, Sulfur, 2 kg, for mercury decontamination, Vermiculite or perlite or cat litter, 5 kg
2. Industrial spill kit, colour-coded to ensure rapid identification, contains absorbent pads, spill containment booms, sucker up 100% organic general-purpose absorbent, personal protection equipment, contaminated waste bags and ties, adhesive wall locator, laminated instruction sheets, 20 litre kit, 32 litre kit.
3.4.3 Chemicals swallowed
The following sequence of procedures should be observed after ingestion of a poisonous substance.
Treatment for an unconscious patient
1. Do not give anything by mouth.
Place patient flat on back and then roll him / her onto the side.
Put your finger in the patient's mouth and remove dentures and any obstructions to breathing.
Hold the patient's jaw well up and forward.
2. Check breathing.
If not breathing, turn casualty on to back and apply E.A.R.
3. Check pulse.
If pulse absent, apply C.P.R.
Loosen clothing around neck, abdomen and chest.
4. If the patient vomits, clean out his / her mouth.
Arrange transport to hospital or doctor.
5. Treatment for a conscious patient
5.1 If the substance swallowed can be identified as a strong acid, a strong alkali or other corrosive, a phenolic substance, kerosene or a petroleum product, or is listed under the poisons first aid list (which should be displayed in an appropriate location), as a substance for which vomiting should not be induced, then do not induce vomiting, but follow the First Aid instructions.
5.2 Give fluids, water or milk only if indicated in the poisons first aid list for the specific poison.
Do not give more than 250 mL of any fluid, because it may induce vomiting.
5.3 If vomiting is to be induced, use syrup of ipecac.
Do not give milk as this increases the risks if aspirated.
If advised by a doctor, or Poisons Information Centre, or if not contradicted above, induce vomiting by the appropriate dose of syrup of ipecac: 30 mL for adult, 15 mL for children, followed by 200 mL of water.
If vomiting has not occurred in 30 minutes, the ipecac syrup may be repeated once only.
5.4 If in doubt about the identity of the poison, do not induce vomiting.
Keep the patient warm, comfortable and calm while waiting and being transported to a hospital.
3.4.4 Chemical vapours and smelling chemicals
See diagram 1.13: Smelling chemicals
1. Isolate chemical vapours by doing experiments in a fume cupboard or use very small quantities of chemicals near an open window with good ventilation.
2. Do not inhale gases directly from the test-tube.
Fill the lungs by breathing in deeply.
Close the mouth then fan the gas towards the nose with the hand and sniff cautiously.
If you detect no odour, move closer and try again.
When you detect the odour, breathe out through the nose again.
3.4.5 Correct names of chemicals
Usually, the chemical name used in this document is the standard name followed by synonyms.
These names were checked with names in the document "Education Queensland, (Australia), Aspects of Science management: A reference manual for Schools".
3.4.6 Corrosive substances
1. Corrosive substances are those that cause severe skin damage.
How corrosive a substance is depends on the length of time taken for the damage to occur.
2. Splashes to the eyes present a far greater risk of severe injury than splashes to skin.
3. Indicators of corrosiveness
3.1 Highly corrosive substances cause visible severe skin damage at the site of contact in less than three minutes.
3.2 Corrosive substances cause visible severe skin damage at the site of contact in a period of three to sixty minutes.
3.3 Irritating substances cause visible severe skin damage at the site of contact in a period of up to four hours.
3.4.7 Disposal of waste chemicals.
1.0 Do not keep any chemicals that do not have labels or are not on a list of chemicals approved by the Ministry of Education.
Ask officials in the Ministry of Education chemists or chemists in a government chemistry laboratory how to dispose of these unwanted chemicals.
1.1 Avoid waste by using chemicals only in those quantities necessary for the learning experience.
1.2 Avoid using the more expensive chemicals, e.g. silver chloride.
1.2 Re-use chemicals not affected by the chemical process.
For example, metals and metal carbonates + acids usually leave residues of unaffected metal and carbonate that may be washed clean and reused.
1.3 Recycle chemicals produced by chemical processes, but only when the process of recycling is simple and not hazardous.
For example, recrystallize copper sulfate crystals from solutions by evaporation or by placing steel wool in the solution overnight.
However, do not recycle lead or mercury salts.
1.4 Do not burn unwanted chemicals, because they may form carcinogenic gases.
2.0 Methods of disposal may include the following:
2.1 Wash down the sink
2.1.1 Waste solutions of most chemicals used in school science experiments may be disposed of down the sink to the sewer.
In some countries the effluent must comply with specific limits for disposal of chemicals to the sewer.
For example: ammonia, limit of 40 grams / day or 29 L of 0.1 M solution / day.
2.1.2 Dilute wastes miscible with water or in solution with a large volume of water.
Then neutralize the diluted solution with sodium carbonate or dilute hydrochloric acid, then wash down the sink, e.g. salt solutions, ethanol.
2.1.3 Treat heavy metal wastes with sodium hydroxide until pH 8-10, then wash down the sink.
2.2 Dispose with normal refuse.
2.2.1 Wrap solid wastes in paper and place in the garbage, e.g. iron filings.
2.2.2 Absorb wastes not miscible with water onto paper or vermiculite or perlite or cat litter, then seal in a plastic bag and place in the garbage.
2.3 Add water or strong alkali and let evaporate in a fume cupboard.
2.4 Waste bottles can be used to store heavy metal wastes and other waste chemicals, to be later taken away by a waste contractor.
2.5 Deliver to a government chemistry laboratory.
3.4.8 Gas or vapour inhalation, EAR, CPR
The following sequence of procedures should be observed for the inhalation of a poisonous substance, e.g. a gas:
1. Carry or drag the patient into fresh air.
Loosen clothing, check breathing, pulse, and pupils of the eyes.
If the patient is not breathing, pulse is absent and eyes are dilated, start Expired Air Resuscitation (EAR) / Cardio-Pulmonary Resuscitation, (CPR).
2. If patient is not breathing, but pulse is present, start Expired Air Resuscitation (EAR).
3. If patient is breathing, but unconscious, place patient flat on the floor, roll the patient onto the right side, remove any dentures and clean the mouth of vomitus.
Keep the patient's chin well up and forward by pushing on the angle of the jaw.
Keep the patient warm.
Do not give the unconscious patient anything by mouth.
If the patient is conscious, encourage the patient to take a series of rapid and deep breaths, then gradually bring the patient into a sitting position.
Make certain the patient does not get up and walk around.
Make the patient lie flat if he or she feels faint.
4. If the heart has stopped beating, CPR can restore blood flow and ventilation.
The compression to the rib cage over the sternum reduces the volume of the thoracic cavity, squeezes the heart and pushes blood into the aorta and pulmonary trunk.
With removal of the pressure, the thorax expands and blood moves into the main veins.
The cycles of compression must be interspersed with cycles of mouth-to-mouth breathing that maintain pulmonary ventilation.
It is difficult to practise CPR on a living person without causing injury, e.g. broken ribs.
3.4.9 Handling and transferring chemicals
Adding chemicals to containers
When adding chemicals to containers in a reaction:
1. Students should not touch any chemical, but use a spatula or gloves.
However, students may be told to feel the texture of chemicals or minerals to determine whether they are crystalline or amorphous.
If students do touch any chemical, they should immediately wash their hands with soap and water.
2. To add chemical to a container, pour the solid chemical into a creased rectangle of clean paper, then tip the chemical from this paper, folded in a V- shape.
3. When taking chemicals from a container, after removing the stopper, keep holding the stopper in one hand so that you can replace it immediately afterwards.
This method ensures that the chemical does not have unnecessary exposure to air and that the correct stopper is replaced.
4. Transfer liquids through a funnel or pour the liquid slowly down a glass rod.
5. Fill pipettes with a pipette-filler and not by sucking by mouth.
3.4.10 Prepare dilute acids and bases, (Safety instructions)
(Safety instructions) 1. Prepare dilute acids by slowly adding ACID TO WATER.
2. Keep concentrated mineral acids, e.g. hydrochloric sulfuric or nitric acids, in a special container on the floor of a locked cupboard.
Only the teacher or a laboratory assistant may handle concentrated acids or strong bases.
3. Wear safety glasses to protect the eyes when handling concentrated acids.
Students may handle dilute mineral acids and bases, but if they spill them on the skin or in the eyes, wash immediately with plenty of water.
4. Organic acids are not so dangerous as mineral acids, but phenol (carbolic acid), and ethanedioic acid-2-water (oxalic acid), are toxic.
5. Strong bases, e.g. sodium hydroxide (caustic soda), and potassium hydroxide (caustic potash), can cause burns.
6. Weaker bases, e.g. calcium hydroxide (limewater, slaked lime), can cause burns if they are left in contact with the skin.
3.4.11 Quantity of chemical to be used in experiments
1. In this document, "dilute solution" refers to a 2 M solution, or a 10% solution, unless otherwise specified.
2. In this document, "concentrated acid", or any other substance, refers to the concentration supplied by chemical suppliers,
e.g. concentrated hydrochloric acid is 36% w / w, unless otherwise specified.
3. For all experiments, unless otherwise instructed, use either:
3.1 a 5 mL of solution, or
3.2 a test-tube filled to the depth of a finger width, or
3.3 the powder on a little finger nail, or
3.4 a piece of solid chemical the size of half a dried pea, or
3.5 no more than one third of a test-tube of any solution.
4. Do not make gas jars full of gas for demonstration purposes.
Use test-tubes with stoppers to collect gases.
3.4.12 Skin contamination
1. The following sequence of procedures should be observed for skin contamination by substances other than phenolics:
Remove contaminated clothing and simultaneously irrigate thoroughly the affected area with water.
Continue drenching for five minutes and then wash the skin gently with a little soap and a lot of water.
Irrigate again with water and cover the affected area with gauze or lint.
2. The following sequence of procedures should be observed for skin contamination by phenolic substances:
Swab off the phenol using swabs soaked in glycerine or vegetable oil.
Discard each swab and continue with a new swab.
Care must be taken to avoid spreading the burn.
3.4.13 Tasting chemicals
Never taste a chemical or any substance in the laboratory except for a few experiments where you are specifically told to taste the chemical.
3.5.0 Chemical hazards
3.5.1 Hazard classifications, NSW Department of Education and Training, (DET), Australia
Toxicity for substances that have been assessed by Worksafe Australia, the following scale is used to describe the level of toxicity
Harmless
Allowed ingredient in human foods, human metabolite or known to be inert in the body, i.e. sodium chloride.
Harmful
Intake of a small amount would probably not cause sickness, e.g. magnesium sulfate.
Slightly toxic
Intake of large amounts may cause sickness, i.e. copper sulfate.
Moderately toxic
Intake of a small amount may cause sickness, i.e. sodium tetraborate.
Highly toxic
Teacher must ensure effective controls are implemented.
Chemical must be used within DET (NSW Department of Education and Training) restrictions
Extremely toxic
Handle with great caution.
Teacher use only, i.e. sodium cyanide.
Toxic
Where the chemical has not been fully assessed and detailed information is not available, the general term "toxic" is used to warn of a possible hazard.
Toxic by all routes
The phrase toxic by all routes of exposure indicates the substance is toxic by ingestion, inhalation and skin contact.
Packing group
I Extreme danger
II Medium danger
III Low danger
UN United Nations number (for Dangerous Goods only)
CAS Number assigned to the chemical in the Individual Chemical Abstracts.
3.6.1 Carbon dioxide soda siphon bulbs, (Safety)
See diagram: 3.3.5 Soda chargers
Aerated water bulbs
Do not use carbon dioxide soda syphon bulbs in science teaching activities, e.g. demonstration of rocketry.
In a recent report, 2014, a student stole a carbon dioxide cylinder from a school laboratory, threw it into a fire at home and was killed by the resulting explosion.
Between 1989 and 1998, the Australian Bomb Data Centre has revealed that there were 1, 011 reports of "soda bombs" being used as explosive devices.
These "bombs" caused injuries and some deaths.
Soda siphon (syphon), bulbs are small metal canisters containing 10 cubic centimetres of either carbon dioxide for soda water, or nitrous oxide to aerate cream.
Such nitrous oxidecanisters have been banned in some countries because of misuse as inhalents.
3.6.3 Eye washing, safety showers
For eye washing, safety showers, the doors in and around preparation rooms are usually locked for security reasons.
However, to enable access to safety shower and eye washing facilities, ensure that connecting doors to preparation rooms are unlocked for science classes.
The first 30 seconds are critical in the treatment of chemical splashes in the eye.
The minimum recommended time for continuation of eye washing is 20 minutes.
Remove contact lenses.
For permanent eye washing fixtures, the water stream should allow continual irrigation of the eye without harmful pressure being placed on it.
You can squeeze an eyewash bottle to irrigate the eye for a short period.
However, a continuous supply of water may still be needed when the eyewash bottle becomes empty.
Regularly empty and refill eyewash bottles to prevent contamination by algae and micro-organisms.
Wearing safety glasses lessens the possibility of eye injury.
Check the water pressure of safety showers or the nearest tap or hose.
Where safety showers are installed, the person affected by a chemical spill should stand in the appropriate place and be thoroughly doused.
Where safety showers are not installed, use the nearest tap or hose.
Check periodically the permanent eye washing and safety shower facilities.
Also, check the water pressure of safety showers or the nearest tap or hose.
3.6.4 Glass wool
Glass wool, Irritant (glass wool, silane-treated)
Glass wool is not recommended for use in school laboratories.
Students should not handle glass wool.
Thin pieces of glass wool can get into cuts and then into the bloodstream.
Do not touch glass wool with the fingers, wear protective gloves.
Do not breathe in glass wool fibres.
Teachers and laboratory assistants may use glass wool in the preparation room, but they should wear an appropriate respiratory mask.
Do not reuse damaged glass wool, because it may release glass fibre particles into the air.
Glass wool is sold as "Glass wool for laboratory use", with suggestions for eye shields, gloves and respirator filters.
3.6.5 Sharps safety
If a demonstration requires any syringes or glass, there may be a broken glass or sharps hazard.
1. A dustpan and brush must be on hand in case of any breakage.
2. Any sharps must be disposed in a special sharps container.
3. Any broken glass must be disposed in a special broken glass container.
4. Gloves must be used when handling broken glass.
5. Goggles must be worn if broken glass fragments occur.
6. Should an injury occur, contact the appropriate authority.
3.6.6 Test-tubes, microscope slides
1. Never look down a test-tube and never point the open end of a test-tube at a student while a reaction occurs.
Hold the test-tube up to the light and look from the side.
Put the test-tube in a test-tube rack before putting chemicals in it.
When heating substances in test-tubes, move the test-tube back and forth across the flame.
Heat substances in wide test-tubes or boiling tubes.
2. When transferring materials from one container to another, hold the containers at arm's length.
Check glassware for cracks before use.
Put broken glass metal pieces and unused chemicals in a specially marked container and bury them.
3. Microscope slides and coverslips are easily broken.
Do not leave broken pieces on the desk.
After each class where microscopes are used, wipe the benches with a damp cloth to remove broken glass, especially broken coverslips.
3.7.1 Storing chemicals - general rules
1. Check reagent solutions and solids regularly and replace used chemicals from stocks or stock bottles.
Label reagent bottles with the name of the substance and the concentration of the solution.
Never return unused reagents to the stock bottles.
2. Store flammable liquids at eye level in a well-ventilated area away from heat sources.
3. Store formalin (solution of formaldehyde (methanal), in water), in glass bottles away from hydrochloric acid.
4. Store organic chemicals inside self-sealing plastic bags.
5. Store strong oxidants and oxidizing agents away from flammable organic chemicals.
Powerful oxidizing agents, e.g. chlorates, peroxides, perchlorates, and perchloric acid, are not usually found in a school science laboratory.
3.7.2 Storing acids, acetic acid
Store concentrated acids in plastic boxes on the floor.
Store acetic acid (ethanoic acid), away from other acids, preferably in another room.
3.7.3 Storing alkalis, ammonia solution
Store alkalis at floor level standing in a strong plastic tray large enough to contain the volume of the container if breakage or spill occurs.
Store concentrated alkalis away from concentrated acids and apart from metals.
Store ammonia solution (10% ammonia solution), as with acids, but separate from them, not near oxidizing agents.
Ammonia solution produces dangerous irritating ammonia fumes.
Carefully unstopper bottles of ammonia solution in a fume cupboard to prevent damage to the eyes from the fumes.
Dilute ammonia solution by adding ammonia solution to water in a fume cupboard.
Store concentrated sodium hydroxide in plastic boxes on the floor, but away from the acids.
Do not use glass stoppers.
3.7.4 Storing chromium (VI) oxide
Chromium (VI) oxide may cause fire on contact with combustible materials and contact with skin may cause severe burns.
Spread soda ash over spillage of chromium (VI) oxide, and use plenty of water.
3.7.5 Storing flammable liquids
Store flammable liquids at eye level in a well-ventilated area away from heat sources.
Flammable liquids may include methylated spirit, nail polish remover, (acetone), cleaning products, paints and glues.
Store strong oxidants away from flammable organic chemicals.
3.7.6 Storing hygroscopic and deliquescent substances
Be careful! Hygroscopic and deliquescent substances may absorb moisture from human tissue and are potentially highly corrosive!
Both hygroscopic and deliquescent substances may absorb moisture from tissue so treat them as potentially highly corrosive.
Hygroscopic substances absorb water from the air, e.g. concentrated NaOH and KOH, concentrated sulfuric acid, glycerine, ethanol,("absolute alcohol").
Deliquescent substances are hygroscopic substances that absorb water to form a concentrated solution of the substance, e.g. calcium chloride.
3.7.7 Storing organic chemicals
Store organic chemicals inside self-sealing plastic bags.
This eliminates the smell associated with such chemicals it also gives early warning of any leaking bottle.
3.7.8 Storing oxidizing agents
Store oxidizing agents in a desiccator away from other chemicals.
Powerful oxidizing agents, e.g. chlorates, peroxides, perchlorates, and perchloric acid, are not often used in a school science laboratory.
Oxidizing materials are chemicals that support combustion or burning.
If they are placed in contact with materials that act as fuels, there is danger of an explosion or fire.
Oxidizing materials include chlorates, peroxides, perchlorates, and perchloric acid.
3.7.9 Storing sodium and potassium
Sodium and potassium react violently with water, and the heat produced can ignite the hydrogen gas evolved.
Contact with skin causes thermal and caustic burns.
Cutting heavily oxidized potassium may cause an explosion, because of the combination of the dioxide with organic material.
Dispose of old stocks of potassium by dissolving the uncut lumps in propan-2-ol.
3.7.10 Storing sodium chlorate and potassium chlorate
Store sodium chlorate and potassium chlorate away from strong acids and any easily oxidized substance.
For example. sulfur, sulfides, phosphorus, sucrose (cane sugar), alcohols, organic solvents, ammonium compounds, powdered metals, oils or grease, and dust.
3.8.1 Workplace Health and Safety
Science teachers are committed to providing and maintaining a healthy and safe work and earning environment for all employees, students and others.
Science teachers must ensure the risk of disease or injury from the school or workplace is minimized for all persons in contact with the school laboratory.
workplace.
Principals, teachers, and all other employees and persons at the school have an obligation for ensuring workplace health and safety at the school.
There is an obligation on employees and other persons at the school to follow instructions for workplace health and safety.
Obligations for workplace health and safety should be ensured by:
1. identifying hazards,
2. assessing risks that may result, because of the hazards,
3. deciding on control measures to prevent, or minimize the level of, the risks,
4. implementing control measures, and
5. monitoring and reviewing the effectiveness of the measures.
3.8.2 Hazard classification and experiments
1. The experiments in this document do not require the use of any chemicals with the following hazard classifications:
Explosive, Oxidizing, Toxic, Radioactive, Highly flammable or Extremely flammable (flash point 21oC), or any chemical specified in the Schedule 1 of the Poison Rules, UK.
However, some experiments requiring the use of propanone, acetone, as a solvent are included.
2. Preparations of small amounts of some dangerous gases are included on the assumption that only experienced science teachers do the experiment and direct observation of these gases has educational value.
These experiments contain the warning: "BE CAREFUL!".
This experiment must be done in a fume cupboard.
3. Another criterion for including some limited handling of dangerous substances by experienced teachers is that students may experience these substances in their daily lives.
Propanone (acetone), was used for nail polish remover, but is being phased out in the modern cosmetic industry.
Chlorine compounds are used for bleaches and water disinfectants.
Sulfuric acid is used in a motor car battery.
4. The warning "Be careful" is used in this document where experiments or procedures require special care.
However, the experiments described have been selected on the basis that a trained science teacher practises them before deciding whether to include them in the teaching programme.
The trained science teacher who has the duty of care must decide which students are allowed to do the experiments themselves and under what conditions.
3.8.3 Laboratory organization
1. Equipment and chemicals are stored in a systematic, orderly and a neat manner.
2. Equipment and chemicals borrowed from a preparation room or storage area is returned to the assigned place.
3. Teaching and storage rooms are uncluttered with no equipment protruding over benches, no dangling wires and no equipment stored on the floor.
4. Bench tops are always clean.
Any spillage is wiped up immediately.
5. Reagent bottles are clearly labelled and filled regularly.
Reagent solutions and solids must be constantly checked and replaced where necessary from stock bottles.
The reagent bottles should be labelled with the name of the substance and the concentration of the solution.
Unused reagents should never be returned to the stock bottles.
6. Sinks are clean and not blocked with waste.
7. Separate waste bins are used for broken glass (which must be wrapped), for paper, for cloth and for solid chemical residues.
8. Water outlets, gas turrets on the benches, power outlets and electrical switches are in good working order.
9. The laboratory and storeroom doors are locked when not occupied.
10. Keep the laboratory safe and sealed! Before leaving the laboratory for the day:
1. Close the windows,
2. Lock away all the equipment,
3. Turn off lights, equipment and computers,
4. Lock all doors.
3.8.4 Risk assessment
Risk assessment, is done once a hazard has been identified, the consequences associated with it need to be determined.
Rik assessment in schools.
The most likely effects to consider would be those that involve direct injury, e.g. cuts, burns, electrocution and poisoning.
Less likely effects might also include those arising from longer term exposure, e.g. exposure to materials containing asbestos.
Risk assessments may vary in complexity depending on the nature and location of the hazardous situation, the personnel and equipment available, and the age and number of students present.
The underlying principle of all risk assessments is the consideration of consequences of the hazardous outcome and the probability or frequency of the occurrence.
In general, when a learning / teaching activity occurs in the teaching of science, the risk is related to the probability of an injury or illness occurring, the duration and frequency of exposure to the hazard, and the consequence or outcome of something going wrong.
The two major types of risk assessment:
1. The potential effects of hazards that are immediate or acute.
These include hazards that are mechanical, electrical, penetrating injuries and some forms of manual handling.
2. The potential effects of hazards that are chronic or long-term hazards.
These include hazards that involve noise, hazardous substances / chemicals, repetitive movements and constrained postures.
Teachers of science should refer to the relevant risk assessment details in HS-10: Workplace Health and Safety.
3.9.8 Scheduling basics
Scheduling is a Australian national classification system that controls how medicines and poisons are made available to the public.
Medicines and poisons are classified into Schedules according to the level of regulatory control over the availability of the medicine
or poison required to protect public health and safety.
Schedule 1 Not currently in use
Schedule 2 Pharmacy Medicine
Schedule 3 Pharmacist Only Medicine
Schedule 4 Prescription Only Medicine OR Prescription Animal Remedy
Schedule 5 Caution
Schedule 6 Poison
Schedule 7 Dangerous Poison
Schedule 8 Controlled Drug
Schedule 9 Prohibited Substance
Schedule 10 Substances of such danger to health as to warrant prohibition of sale, supply and use
The Schedules are published in the Poisons Standard and are given legal effect through state and territory legislation.
The Poisons Standard is also referred to as the Standard for the Uniform Scheduling of Medicines and Poisons (SUSMP).
The Scheduling Handbook provides guidance on the pathway a scheduling application may follow and other details of the scheduling process.
3.1.0 Chemicals Not permitted in schools, Australia
Banned chemicals
4-aminobiphenyl, Extremely toxic, carcinogenic
Ammonium compounds
Ammonium chlorate, Violently explosive
Ammonium perchlorate, Violently explosive
Anaesthetic ether, diethyl ether, Extremely flammable
Aniline, phenylamine, Extremely toxic, carcinogenic
Arsenic and compounds
Arsenic, Extremely toxic, carcinogenic
Arsenic triiodide, arsenic (III) iodide, Extremely toxic, carcinogenic
Arsenic trioxide, arsenic (III) oxide, Extremely toxic, carcinogenic
Arsenic (III) iodide, arsenic triiodide, Extremely toxic, carcinogenic
Arsenic (III) oxide, arsenic trioxide, Extremely toxic, carcinogenic
Arsenious acid, arsenic trioxide, toxic, carcinogenic
Asbestos
Asbestos, crocidolite, blue asbestos, Extremely toxic if inhaled into lungs, carcinogenic
Benzene, benzol, Extremely toxic, carcinogenic
Benzidine, 4,4'-diaminobiphenyl, Highly toxic and carcinogenic
Benzol, benzene, Extremely toxic, carcinogenic
Beryllium, metal, Highly toxic and carcinogenic
Beryllium chloride, Highly toxic and carcinogenic
Bis(chloromethyl) Ether, dichlorodiniethyl ether, Highly toxic and carcinogenic
Blue asbestos, asbestos, Extremely toxic if inhaled into lungs, carcinogenic
Cadmium and compounds
Cadmium, Highly toxic
Cadmium carbonate, Highly toxic
Cadmium chloride, Highly toxic
Cadmium oxide, Highly toxic
Cadmium sulfate, Highly toxic
Carbazotic acid, picric acid, Explosive when dry and compacted
Carbon disulfide, Extremely flammable, extremely toxic
Carbon tetrachloride, tetrachloromethane, Extremely toxic, possibly carcinogenic
Chloral, trichloroacetaldehyde, Moderately toxic, drug addiction
Chloral hydrate, 1,1,1-trichloroethanediol, Moderately toxic, drug addiction
Chloric acid, chloric (V) acid, Violently explosive mixtures with combustible materials
Chloric (VII) acid, perchloric acid, Violently explosive mixtures with combustible materials
Chloroform, Toxic
Chromium compounds
Copper arsenite, copper acetoarsenite, CuAsHO3, Toxic
Crocidolite, asbestos, Extremely toxic if inhaled into lungs, carcinogenic
Di(2-chloroethyl) ether, 2,2'-dichlorodiethyl ether, Highly toxic
4,4'-Diaminobiphenyl, benzidine, Highly toxic and carcinogenic
3,3'-Dichlorobenzidine, dichlorobiphenyl-4,4'-diamine, Highly toxic
Dichlorobiphenyl-4,4'-diamine, 3,3'-dichlorobenzidine, Highly toxic and carcinogenic
2,2'-Dichlorodiethyl ether, Highly toxic
Dichlorodimethyl ether, bis-(chloromethyl) ether, Highly toxic and carcinogenic
Diethyl ether, anaesthetic ether, ether, sulfuric ether, ethoxyethane, Extremely flammable
Diethyl sulfate, Extremely toxic, probably carcinogenic
Dimethyl sulfate, Extremely toxic, probably carcinogenic
3,3'-Dimethylbiphenyl-4,4'-diamine, o-tolodine, Highly toxic, carcinogenic impurities
4-Dinitrobiphenyl, Highly toxic, carcinogenic impurities
Ether, diethyl ether, Extremely flammable
Ethoxyethane, diethyl ether, Extremely flammable
Ethylene oxide, oxirane, oxiran, Extremely toxic, carcinogenic
5-Fluorouracil, Highly toxic
Hardite, Extremely toxic, carcinogenic
Hydrocyanic acid, hydrogen cyanide, Extremely toxic
Hydrofluoric acid, Extremely toxic
Hydrogen cyanide, hydrocyanic acid, Extremely toxic
Lithium aluminium hydride, lithium tetrahydroaluminate, Explosive mixture if fine particles mixed with air
Lithium tetrahydroaluminate, Lithium aluminium hydride, Explosive mixture if fine particles mixed with air
Magnesium perchlorate, anhydrone, Violently explosive mixtures with combustible materials, organic compounds, ammonium compounds
Mercury and compounds
Magnesium perchlorate, anhydrone
Naphthalene compounds
4-Nitrobiphenol, Extremely toxic, carcinogenic
Nitrogen triiodide, Explosive when dry
Nitrosophenols
Osmium tetroxide, osmic acid, Highly toxic, carcinogenic impurities
o-Tolodine, Highly toxic if ingested
Oxirane, oxiran, ethylene oxide, Extremely toxic, carcinogenic
PCBs, Moderately toxic, probably carcinogenic
Perchloric acid
Phenol, carbolic acid
Phenylamine, aniline, Extremely toxic
Phosphorus, white, white phosphorus
Picric acid, 2,4,6-trinitrophenol
Polychlorinated biphenyls, PCBs, Moderately toxic, probably carcinogenic
Potassium and compounds
Sodium
Sodium amide, sodamide, Highly toxic, flammable, reacts violently with water
Sodium azide, Extremely toxic
Sodium chlorate, Violently explosive mixtures with combustible materials
Sodium cyanide, Extremely poisonous, with acids forms toxic hydrogen cyanide gas
Sodium perchlorate, Violently explosive mixtures with combustible materials
Sodium peroxide, Violently explosive mixtures with combustible materials
Sulfuric ether, diethyl ether, Extremely flammable
Tetrachloromethane, carbon tetrachloride, Extremely toxic, possibly carcinogenic
Thallium compounds
o-Tolidine, 3,3'-dimethylbiphenyl-4,4-diamine, Highly toxic, carcinogenic impurities
Trichloroacetaldehyde, chloral, Moderately toxic, drug addiction
1,1,1-Trichloroethanediol, chloral hydrate, Moderately toxic, drug addiction
Trinitrophenol, picric acid, Explosive when dry and compacted