Form 4 · Introduction to Biology and Laboratory Rules

Safety and Rules in the Biology Laboratory

Laboratory safety in biology covers hazard symbols, correct handling of apparatus, chemicals and living specimens, and the general and emergency rules that keep a practical class safe.

What this standard covers

Content standard 1.2 requires you to recognise laboratory hazard symbols, state general laboratory rules, and explain safe handling of apparatus, chemicals, specimens and microorganisms during practical work. It also covers what to do in an emergency.

Hazard symbols and their meanings

Common hazard symbols found on chemical and specimen containers in the biology laboratory.
Symbol meaningWhat it warns you about
CorrosiveSubstance can burn or destroy skin, eyes and other materials on contact
ToxicSubstance can cause serious harm or death if swallowed, inhaled or absorbed
FlammableSubstance catches fire easily; keep away from open flame or heat
IrritantSubstance can cause redness, itching or inflammation of skin or eyes
BiohazardMaterial may contain organisms that can cause infection or disease

General and emergency rules

  • Wear a lab coat, and safety goggles when handling chemicals or dissecting specimens.
  • Never eat, drink or taste anything in the laboratory.
  • Read chemical and specimen labels carefully before use, and never handle a substance whose label you have not checked.
  • Report every spill, breakage, cut or burn to the teacher immediately, however small.
  • Know the location of the fire extinguisher, first-aid box, eyewash station and emergency exit before starting practical work.
  • Dispose of broken glass, sharps, chemical waste and biological specimens only in the containers provided, never in the normal bin.

How it is examined

Exam questions typically show a hazard symbol and ask you to state its meaning and one precaution linked to it, or describe a laboratory situation (for example, a spilt acid or an improperly stored specimen) and ask you to identify the safety rule that was broken and the correct action. Paper 1 items often test matching a symbol to its correct meaning.

Safe handling of specimens and microorganisms

Preserved animal specimens are usually stored in formalin or alcohol, both of which give off fumes that irritate the eyes and airways, so dissection should be carried out in a well-ventilated area, with gloves worn to avoid skin contact with the preservative. When culturing microorganisms, aseptic technique is essential: an inoculating loop is flame-sterilised before and after use, a culture plate is opened only briefly and never near a draught, and it is sealed with tape once inoculated so that microorganisms cannot escape and contaminate the surroundings or the handler.

Cultures and used plates are sterilised, usually by autoclaving, before disposal, since an unidentified microorganism could be pathogenic.

Worked exam-style question

Question. During a practical lesson, a student notices a bottle of concentrated hydrochloric acid has been left open on the bench with no hazard label visible, and a classmate is about to pour some into a beaker without wearing safety goggles. (a) Identify the hazard symbol that should appear on this bottle, and state what it warns of.

(b) State two laboratory rules that are being broken in this situation. (c) Suggest the correct action the student should take immediately.

(d) State one item of safety equipment the teacher should ensure is accessible before allowing acid to be used.

Model answer. (a) The corrosive symbol; it warns that the substance can burn or destroy skin, eyes and other materials on contact. (b) Two rules are broken: chemicals must not be used without a hazard label being checked, and safety goggles must be worn when handling chemicals.

(c) The student should stop the classmate immediately and inform the teacher, ensuring goggles are worn and the container is properly closed and labelled before any further handling. (d) The eyewash station should be accessible.

Practice question

Try this. A student wants to observe a sample of pond water containing unidentified microorganisms under a microscope. State one precaution the student should take when handling the sample, and explain why it is necessary.

Exam tip

Key terms

These terms from the wider scientific-investigation process come into play once you begin conducting an experiment safely:

  • Manipulated variable, the factor you deliberately change, which must still be handled following safe procedures.
  • Controlled variable, a factor kept constant, sometimes for safety reasons as well as fairness.
  • Inference, a reasonable explanation drawn from an observation, such as inferring the cause of a spill from what you observe.

Source:SRC-DSKP-EN

Frequently asked questions

What should I do if a chemical splashes on my skin during a practical?
Rinse the affected area immediately with plenty of running water for several minutes and inform the teacher at once. Continue to follow the teacher's instructions, which may include using the eyewash station if the chemical reached the eyes, or seeking first aid. Reporting quickly, even for a small splash, is part of correct laboratory conduct.
Why must specimens and chemicals never be handled without checking the label first?
Labels identify the hazard symbol, concentration or species of the specimen, and any special handling instructions. Handling an unlabelled or unchecked substance risks exposure to a corrosive, toxic or biohazardous material, or contamination of a living specimen, so checking the label is a basic safety step before any laboratory task.
Why must microorganism cultures be sterilised before disposal?
An unidentified culture could contain a pathogenic microorganism capable of causing infection or disease. Sterilising a culture, usually by autoclaving it at high temperature and pressure, kills the microorganisms present so that the waste can be disposed of safely, without risking infection to anyone who later handles it or comes into contact with the bench.

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