Science Laboratories, Safety and First Aid

What to remember

• A science laboratory is the place for learning by doing. It must be well planned, well stocked, clearly labelled and supervised at all times.
• Safety rules protect people before any result matters. Never taste or smell chemicals directly, always add acid to water, and know where the fire and first-aid equipment is kept.
• First aid is the first help given before a doctor arrives. Its aims are to save life, prevent the injury from becoming worse and help recovery.

Need and types of science laboratory

Science is learned best by observation and experiment. A laboratory allows children to handle apparatus, test ideas, record data and draw conclusions. It builds scientific skills (observation, measurement, inference) and scientific attitude (honesty, patience, open mind).

Laboratory arrangements in schools:

• Central (general) laboratory: one room used for all science classes.
• Separate laboratories: one each for physics, chemistry and biology, usual in higher classes.
• Classroom laboratory or science corner: small kits and simple apparatus in the classroom, important for primary and upper primary stages.
• Mobile or portable laboratory: a kit carried from class to class or school to school.

Planning a laboratory

Good planning includes:

• Location: ground floor, easy to reach, away from noise, with an outside exit, and with a source of water and electricity.
• Light and ventilation: large windows, an exhaust fan or fume cupboard, and enough natural light.
• Space: enough room for movement and group work.
• Tables: smooth, heat-resistant and acid-resistant working tops with sinks and water points.
• Storage: closed cupboards for chemicals, open racks for apparatus, and a separate store room.
• Safety fittings: fire extinguisher, sand bucket, first-aid box, eyewash and an emergency exit.
• Display: a board for rules, charts and a list of students' duties.

The laboratory should have a preparation room and a place for the teacher's demonstration table, raised so that all children can see.

Management of the laboratory

• Keep a stock register (for permanent items) and a consumable register (for chemicals and items used up). Check stock at fixed times.
• Label every bottle clearly with the name, formula and hazard sign. Never use unlabelled bottles.
• Store chemicals by type, not in alphabetical order alone. Keep acids low, keep flammable liquids away from heat, and keep oxidizers away from fuels.
• Assign a lab assistant or student duty roster for cleaning and arranging.
• Keep a breakage and accident register.
• Plan experiments in advance so that apparatus and chemicals are ready.
• Show demonstration experiments first when there is a hazard, and let children do only safe parts.

Safety rules in the laboratory

General rules:

• 1. Do not enter or work without the teacher's permission.
• 2. Wear an apron or coat, and safety goggles for chemical work. Tie long hair, and wear covered footwear.
• 3. Do not eat, drink or run in the lab.
• 4. Never taste a chemical. Smell only by gently wafting the vapour towards the nose.
• 5. Do not point the mouth of a heated test tube towards any person.
• 6. Read the label twice before using a chemical.
• 7. Always add acid to water slowly, not water to acid, because the heat released can make the acid splash.
• 8. Do not pipette by mouth; use a pipette filler or a dropper.
• 9. Use a fume cupboard for toxic or smelly gases.
• 10. Keep flammable liquids such as alcohol and ether away from flames.
• 11. Heat liquids in a test tube using a test-tube holder and move it gently.
• 12. Wash hands after the practical.
• 13. Dispose of waste properly: used chemicals in labelled waste bottles, broken glass in a separate bin.
• 14. Do not return unused chemicals to the stock bottle.
• 15. Report every accident or breakage to the teacher at once.

Storage of special substances:

Hazard symbols found on chemical labels warn of: flammable, corrosive, toxic (poison), explosive, oxidizing and harmful to the environment. Teachers must teach children to read these signs.

Fire safety

Fire needs three things: fuel, heat and oxygen, called the fire triangle. Removing any one puts out a fire.

Basic actions in a lab fire:

• Switch off gas and electricity first.
• Use sand or a fire blanket on a small fire.
• Cover a burning beaker with a wet cloth or a watch glass to cut the oxygen.
• Raise the alarm and move people out calmly.

First aid

First aid is immediate help given to an injured or suddenly ill person. The teacher must also know when to call a doctor or ambulance (emergency number 108 in AP is for ambulance services).

Contents of a school first-aid box: sterilised gauze and cotton, bandages, adhesive plaster, antiseptic lotion, scissors, forceps, safety pins, burn ointment, a thermometer, an eye wash cup, a torch and a list of emergency numbers. Medicines should be checked regularly for expiry.

Common situations and actions:

The standard first-aid habits: stay calm, remove danger, check breathing, stop bleeding, comfort the person, call for help.

Common apparatus and their care

Biology laboratory points: specimens are kept in a preservative such as formalin (use gloves and ventilation); dissect only what the curriculum permits; and wash hands thoroughly after handling specimens or soil. Living animals are handled with kindness and returned to nature when possible. Electrical points: use properly earthed sockets, keep wires insulated, keep hands dry, and switch off before changing a connection.

Exam traps

• 1. Add acid to water, not water to acid.
• 2. Sodium is kept in kerosene; phosphorus is kept in water.
• 3. Foam or sand for oil fire; water is wrong for oil and electrical fires.
• 4. Acid burn needs a weak base; alkali burn needs a weak acid after thorough washing with water.
• 5. Stock register vs consumable register: one for permanent items, the other for things used up.
• 6. Fire triangle: fuel, heat, oxygen; not water.
• 7. Fume cupboard removes harmful fumes; a fire blanket smothers flames.
• 8. First aid is not treatment; it is help until professional care arrives.

One-liners

• 1. Always add concentrated acid slowly to water while stirring.
• 2. Sodium metal is stored in kerosene.
• 3. White phosphorus is stored under water.
• 4. Silver nitrate is kept in a dark bottle.
• 5. The fire triangle has fuel, heat and oxygen.
• 6. A carbon dioxide extinguisher is suitable for electrical fires.
• 7. Never taste or smell chemicals directly.
• 8. Wear safety goggles and an apron during chemical work.
• 9. A fume cupboard carries toxic gases out of the room.
• 10. For a heat burn, cool the area under running water.
• 11. In electric shock, first switch off the supply.
• 12. A first-aid box must be checked regularly for expiry dates.

Practice questions

1. While diluting a concentrated acid in the laboratory, one should

   1. add the acid slowly to water with stirring
   2. add water quickly to the acid
   3. pour both together at once
   4. heat the water first and add acid
   Answer

   A. add the acid slowly to water with stirring

   Adding acid to water spreads the heat released and avoids splashing.

2. Sodium metal is stored under

   1. alcohol
   2. dilute acid
   3. water
   4. kerosene
   Answer

   D. kerosene

   Sodium reacts with water and air, so it is kept in kerosene.

3. White phosphorus is stored under

   1. kerosene
   2. oil of cloves
   3. water
   4. air
   Answer

   C. water

   Water prevents contact with air, where white phosphorus catches fire.

4. Silver nitrate solution is kept in a dark bottle because it

   1. freezes at room temperature
   2. is a gas
   3. is affected by light
   4. is very heavy
   Answer

   C. is affected by light

   Light slowly decomposes silver nitrate.

5. The three components of the fire triangle are

   1. heat, nitrogen and water
   2. oxygen, sand and fuel
   3. fuel, water and carbon dioxide
   4. fuel, heat and oxygen
   Answer

   D. fuel, heat and oxygen

   Removing any one of the three puts out the fire.

6. Which method is suitable for an electrical fire after switching off the supply?

   1. Water jet
   2. Carbon dioxide extinguisher
   3. Bucket of tap water
   4. Wet cloth on the wires
   Answer

   B. Carbon dioxide extinguisher

   Water conducts electricity and is unsafe on electrical fires.

7. Which is the best first action for a small oil fire in a beaker?

   1. Pour water on it
   2. Cover with sand or a watch glass
   3. Blow on it
   4. Carry it outside
   Answer

   B. Cover with sand or a watch glass

   Cutting off oxygen puts out the fire; water spreads burning oil.

8. Which of the following is the first step for a person who has received an electric shock?

   1. Give hot tea
   2. Pour water on the person
   3. Pull the person with bare hands
   4. Switch off the electric supply
   Answer

   D. Switch off the electric supply

   Touching the person while current flows can shock the helper.

9. A person's clothes catch fire. The best immediate action is to

   1. roll the person on the floor or cover with a fire blanket
   2. fan the flames
   3. ask the person to run
   4. pour oil on the clothes
   Answer

   A. roll the person on the floor or cover with a fire blanket

   Smothering cuts off oxygen.

10. Which of the following should NOT be done in a chemistry laboratory?

    1. Reading the label twice
    2. Using a fume cupboard
    3. Tasting a chemical to identify it
    4. Wearing safety goggles
    Answer

    C. Tasting a chemical to identify it

    Never taste laboratory chemicals.

11. A fume cupboard is used to

    1. remove toxic or smelly gases from the working area
    2. store acids
    3. dry glassware
    4. keep the lab cool
    Answer

    A. remove toxic or smelly gases from the working area

    It carries harmful fumes out of the room.

12. Which should be done if acid falls on the skin?

    1. Apply acid again to neutralize
    2. Apply a strong alkali
    3. Rub with dry cloth
    4. Wash with plenty of water, then use a very dilute bicarbonate solution
    Answer

    D. Wash with plenty of water, then use a very dilute bicarbonate solution

    Water dilutes the acid, and a weak base neutralizes the remainder.

13. For an alkali burn on the skin, after washing with water the best treatment is

    1. dry sodium carbonate
    2. a very dilute acetic acid or boric acid solution
    3. a strong sodium hydroxide solution
    4. petrol
    Answer

    B. a very dilute acetic acid or boric acid solution

    A weak acid neutralizes the remaining alkali.

14. If a chemical splashes into the eye, the first aid is to

    1. close the eye and wait
    2. rub the eye
    3. wash with plenty of clean water for several minutes
    4. apply oil
    Answer

    C. wash with plenty of clean water for several minutes

    Prolonged rinsing removes the chemical.

15. For a minor burn by heat, the correct first aid is to

    1. cover with oil
    2. burst the blisters
    3. hold the area under cool running water
    4. apply toothpaste
    Answer

    C. hold the area under cool running water

    Cooling reduces damage; oils and pastes may cause infection.

16. A person has fainted. A suitable first aid step is to

    1. make the person stand
    2. lay the person flat and raise the legs
    3. pour water on the face
    4. give a heavy meal
    Answer

    B. lay the person flat and raise the legs

    Raising the legs helps blood flow to the brain.

17. Which of the following is the correct way to smell a gas in the laboratory?

    1. Hold the container against the nose
    2. Inhale deeply from the container
    3. Taste a little
    4. Gently waft the vapour towards the nose
    Answer

    D. Gently waft the vapour towards the nose

    Direct inhaling can harm the lungs.

18. Pipetting by mouth is avoided because

    1. the liquid may be poisonous or corrosive
    2. it makes the liquid warm
    3. it is slow
    4. it needs more skill
    Answer

    A. the liquid may be poisonous or corrosive

    Use a pipette filler or dropper instead.

19. A heated test tube should be

    1. pointed away from every person
    2. closed with a cork
    3. pointed towards the nearest friend
    4. held with bare fingers
    Answer

    A. pointed away from every person

    Hot liquid can spurt out suddenly.

20. A stock register is maintained for

    1. student attendance
    2. the timetable
    3. chemicals that get used up
    4. permanent apparatus and equipment
    Answer

    D. permanent apparatus and equipment

    Consumables are entered in a separate register.

21. Which statement about storage of chemicals is correct?

    1. Every bottle should carry a clear label with its name and hazard
    2. Unlabelled bottles can be used if they look familiar
    3. All chemicals can be placed together in one shelf
    4. Bottles are labelled only when empty
    Answer

    A. Every bottle should carry a clear label with its name and hazard

    Clear labelling prevents accidents.

22. Concentrated nitric acid is kept in a dark bottle mainly because

    1. it is a solid
    2. it decomposes in light
    3. it cools in the dark
    4. it floats on water
    Answer

    B. it decomposes in light

    Light causes slow decomposition, so dark bottles are used.

23. Which of the following is placed in a typical school first-aid box?

    1. Strong acid solution
    2. Sodium metal
    3. Sterilised gauze and antiseptic lotion
    4. Matches and kerosene
    Answer

    C. Sterilised gauze and antiseptic lotion

    A first-aid box has dressings, antiseptic and basic tools.

24. The primary aim of first aid is to

    1. give strong medicines
    2. save life and prevent the condition from becoming worse
    3. find the cause of the injury
    4. replace the doctor
    Answer

    B. save life and prevent the condition from becoming worse

    First aid is temporary help until medical care arrives.

25. Where should a school science laboratory ideally be located?

    1. Next to a noisy road
    2. On the top floor without water supply
    3. On the ground floor with good light and ventilation
    4. In the basement without windows
    Answer

    C. On the ground floor with good light and ventilation

    Easy access, ventilation and an outside exit improve safety.

26. A reaction releases a poisonous gas. Where should the demonstration be done?

    1. On a crowded student table
    2. Next to the door
    3. Near a closed window
    4. In a fume cupboard
    Answer

    D. In a fume cupboard

    Poisonous gases must be carried away from the room.

27. Why should unused chemicals not be returned to the stock bottle?

    1. They change colour in the bottle
    2. They may contaminate the stock
    3. They become heavier
    4. They lose their label
    Answer

    B. They may contaminate the stock

    Returning chemicals can spoil the whole stock.

28. Which fire extinguisher or material is NOT suitable for a flammable liquid fire?

    1. A water jet
    2. Sand
    3. Foam
    4. Dry chemical powder
    Answer

    A. A water jet

    Water can spread burning oil.

29. Why is a Bunsen burner flame adjusted to blue before heating?

    1. It uses more gas
    2. It is easier to see
    3. A blue flame is hotter and does not leave soot
    4. It is cooler and safer
    Answer

    C. A blue flame is hotter and does not leave soot

    The non-luminous blue flame gives complete combustion.

30. A student sprains a wrist during a practical. The first aid is to

    1. massage it strongly
    2. let the student continue writing
    3. pull the wrist
    4. keep the part still and support it with a bandage or sling
    Answer

    D. keep the part still and support it with a bandage or sling

    Rest and support limit further injury.

31. A broken thermometer spills mercury. The teacher should

    1. let children play with it
    2. sweep it with a broom quickly
    3. ask children to move away and clean carefully without touching it
    4. wash it down the sink with hot water
    Answer

    C. ask children to move away and clean carefully without touching it

    Mercury vapour is toxic; avoid touching and clean with care.

32. Which of the following statements is/are correct? 1. Water should be added to concentrated acid. 2. Sodium is stored under kerosene.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    Acid is added to water; sodium is kept in kerosene.

33. Which of the following statements is/are correct about fire safety? 1. Removing oxygen can extinguish a fire. 2. Water is the best method for an electrical fire.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Water conducts electricity and is not suitable for electrical fires.

34. Which of the following statements is/are correct? 1. White phosphorus is stored under water. 2. A fume cupboard removes harmful gases.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both statements are standard laboratory practice.

35. Which of the following statements is/are correct? 1. A burn by heat should be covered with oil. 2. Blisters should be burst for faster healing.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    D. Neither 1 nor 2

    Cool the burn with water; do not apply oil or break blisters.

36. Which of the following statements is/are correct about laboratory management? 1. A stock register lists permanent apparatus. 2. Consumables such as chemicals are recorded separately.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both registers are kept for proper control.

37. Which of the following statements is/are correct about first aid? 1. It is given before medical help reaches the person. 2. It is a full treatment that replaces a doctor.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    First aid is only first help.

38. Which of the following statements is/are correct about acid and alkali burns? 1. Wash first with a large amount of water. 2. Use a strong neutralizing chemical immediately.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Wash first; weak, dilute neutralizers only if advised.

39. Which of the following statements is/are correct about the laboratory rules? 1. Hair should be tied and an apron worn for chemical work. 2. Eating food in the laboratory is allowed if hands are clean.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Eating and drinking are not allowed in the lab.

40. Match the substance with its safe storage. P. Sodium Q. White phosphorus R. Silver nitrate

    1. P-dark bottle, Q-water, R-kerosene
    2. P-kerosene, Q-dark bottle, R-water
    3. P-water, Q-kerosene, R-dark bottle
    4. P-kerosene, Q-water, R-dark bottle
    Answer

    D. P-kerosene, Q-water, R-dark bottle

    Sodium is stored under kerosene, white phosphorus under water, silver nitrate in dark bottles.

41. Match the fire with the suitable extinguishing material. P. Paper fire Q. Electrical fire R. Oil fire

    1. P-carbon dioxide, Q-water, R-sand
    2. P-water, Q-carbon dioxide, R-sand or foam
    3. P-foam, Q-water, R-carbon dioxide
    4. P-sand, Q-water, R-water
    Answer

    B. P-water, Q-carbon dioxide, R-sand or foam

    Water suits paper, CO2 suits electrical fires, sand or foam suits oil fires.

42. Match the injury with first aid. P. Heat burn Q. Chemical in eye R. Electric shock

    1. P-apply oil, Q-wash with oil, R-pull the person
    2. P-wash with water, Q-switch off power, R-apply oil
    3. P-switch off power, Q-cool water, R-wash with water
    4. P-cool running water, Q-wash with water, R-switch off power
    Answer

    D. P-cool running water, Q-wash with water, R-switch off power

    Each injury has a standard first aid step.

43. Which of the following is the correct order of first aid for a bleeding cut?

    1. Remove all clothing, then press
    2. Apply pressure with a clean cloth, raise the limb, then clean and dress
    3. Leave open to dry, then cover
    4. Apply oil, wait, then wash
    Answer

    B. Apply pressure with a clean cloth, raise the limb, then clean and dress

    Pressure and elevation control bleeding.

44. A teacher plans a practical on heating a liquid. Which preparation reduces risk the most?

    1. Skipping goggles to save time
    2. Starting the heating while students watch
    3. Allowing students to choose the chemicals
    4. Reading the procedure and checking apparatus before the class
    Answer

    D. Reading the procedure and checking apparatus before the class

    Prior planning and checking prevent most accidents.

45. Which of the following is a hazard symbol type seen on chemical labels?

    1. Digestive
    2. Musical
    3. Corrosive
    4. Magnetic
    Answer

    C. Corrosive

    Corrosive, flammable, toxic and explosive signs warn of danger.