IB Biology HLPractical SkillsPaper 1B & IA~11 min read
Safety, Ethics & the Environment
Marks for safety and ethics are some of the easiest in the whole course to pick up, and some of the most commonly thrown away. The reason is almost always the same: students write a generic sentence about lab coats instead of saying what the specific hazard is and what they are doing about it.
📚 What you need to know
A hazard is a feature of a procedure that is inherently harmful. A risk is the level of danger that hazard poses.
Risk depends on the likelihood of harm occurring and the severity of the harm if it does.
A risk assessment must identify hazards, assess the level of risk, and alter the procedure to minimise it.
Hazard warning symbols are standardised pictograms shown in a red diamond on a white background. There are nine in total.
The IB policy on animals in schools: only involve animals where no alternative exists, never be cruel, and include measures that remove causes of distress.
Any investigation involving humans needs fully informed consent.
Environmental care means correct disposal of waste in the lab, and minimising impact in the field.
Hazard and risk are not the same word
Students use these interchangeably in everyday speech, but in an exam they mean different things and swapping them costs marks.
The distinction
A hazard is what could cause harm • A risk is how likely that harm is, and how bad it would be
Examples of hazards: a chemical that is an irritant to the skin; the slippery rocks of a rocky shore; a Bunsen burner that can cause burns. Each of those is inherently harmful whether or not anyone is near it. The risk only appears once you consider who is doing what with it.
This is why the same hazard can carry very different risks. A Bunsen burner on an unattended bench in a crowded room is a much higher risk than the same burner used carefully by one person, even though the hazard has not changed at all.
A precaution can work on either axis. Wearing goggles reduces the severity if splashing happens; using a smaller volume of the chemical reduces the likelihood. Saying which one you are doing is what turns a description into an evaluation.
A worked risk assessment
Take a rocky shore quadrat practical.
🧩 Identify, assess, minimise
Identify: slippery rocks on the rocky shore are a hazard.
Assess: slipping and falling is quite likely on wet rock, and could lead to injuries such as bruises or a twisted ankle.
Minimise: footwear must have a good grip, students should avoid stepping onto rocks covered with seaweed, and should walk slowly and with care.
Notice that step 3 is written as a change to the method, not as a vague intention. “Be careful” is not a control measure. “Avoid stepping on seaweed-covered rock” is.
Chemicals and hazard symbols
Plenty of biology practicals involve chemicals with real hazards — the stains used when viewing cells, the chemicals used when measuring enzyme reaction rates, and the solvents used in chromatography.
The safety of a chemical is communicated by its hazard warning symbols, standardised pictograms found on labels and safety data sheets. There are nine in total, each shown inside a red diamond with a white background. These six are the ones you are most likely to meet.
The other three cover gases under pressure, explosives and serious longer-term health effects. You are not expected to draw them, but you should not be surprised by one on a bottle.
The single most common way to lose a safety mark is writing “wear a lab coat and goggles”. That is standard practice in every laboratory, so it tells the examiner nothing. Name the hazard, then justify the precaution: “iodine solution is an irritant, so the risk of harm is reduced by wearing safety goggles and washing immediately any skin it contacts.”
Ethical considerations
Biology investigations often involve living organisms, which is exactly why ethics matter here more than in the other sciences.
Animals
The IB policy on animals in schools is clear: investigations should only involve animals where no alternative exists. Any investigation that must involve animals should not be cruel, and must include measures that remove potential causes of animal distress.
In practice this means:
Choosing an experiment that does not involve animals in the first place, if one is available.
If one is unavoidable, minimising potential harm: keeping experiments short, handling animals as little as possible, and releasing them to their natural environment at the end.
Humans
Any experiment involving humans — using a spirometer to measure breathing rate, for example — needs the fully informed consent of the person involved. “Informed” is the operative word: they must know what will be done, why, and that they can withdraw.
Situation
What makes it an ethical issue
A reasonable response
Investigating woodlouse behaviour in a choice chamber
The animals may be stressed by handling, light or drying out
Keep the trial short, handle with a soft brush, return them to where they were collected
Measuring classmates’ pulse rates after exercise
Participants may have a medical condition, and personal data is involved
No animal was killed for the practical, but respectful handling still applies
Use material from a food-supply source, dispose of it correctly afterwards
Growing bacteria on agar plates
Cultures could contain harmful organisms
Incubate below body temperature, tape plates, never open them, autoclave before disposal
Environmental considerations
You also need to consider the potential environmental impact of your investigation.
In the laboratory
Mostly this comes down to disposing of waste correctly:
Not pouring toxic chemical waste down the sink.
Putting sharp equipment in a sharps bin.
Disposing of biological waste — petri dishes with bacteria, dissected organs — correctly, rather than in a normal bin.
In the field
Here it means minimising your impact on the habitat you came to study:
Not working in very large groups, which causes trampling.
Avoiding sensitive environments such as nesting sites or fragile dune systems.
Taking all equipment and litter away with you.
The irony worth mentioning in an IA. Field ecology risks damaging the very thing being measured. Fifteen students walking the same transect line compact the soil and crush the vegetation, which can change the results of the next group. Saying so shows genuine evaluation rather than a copied list.
Worked examples
WE 1
Writing a safety precaution properly
A student investigates the effect of temperature on catalase activity using hydrogen peroxide, which is an irritant and an oxidising agent, in a water bath heated to 60 °C. State two hazards and, for each, a precaution with a justification. (4 marks)
Hazard 1 and precaution
Hydrogen peroxide is an irritant that can damage the eyes and skin. Safety goggles should be worn and any skin contact washed immediately, which reduces the severity of harm should splashing occur.
Hazard 2 and precaution
The hot water bath at 60 °C can cause scalds. Tubes should be moved with tongs and the bath placed away from the bench edge, which reduces the likelihood of spillage onto skin.
Why this scores
Each answer names the hazard, states a specific action, and explains what it achieves.
Hazard, then action, then the reason the action works“wear goggles” on its own would score nothing here — there is no hazard named and no justification.
WE 2
Evaluating an ethical decision
A student plans to investigate whether woodlice prefer damp or dry conditions by keeping them in a choice chamber for two hours. Suggest two ethical improvements to this plan. (3 marks)
Improvement 1: shorten the exposure
Two hours is long enough for woodlice to dry out and become distressed on the dry side. The trial should be reduced to a few minutes, which is long enough to record a preference.
Improvement 2: handling and release
Handle them as little as possible, using a soft brush rather than fingers, and release them back to where they were collected at the end.
The wider point
The IB policy requires that animals are only used where no alternative exists, and that measures are taken to remove causes of distress.
Shorten it, handle it less, put it backnotice this question rewards knowing the reason two hours is a problem, not just saying it is too long.
WE 3
Hazard versus risk
A teacher says that a Bunsen burner is “a hazard, but not necessarily a high risk”. Explain what is meant by this. (3 marks)
Point 1: define the hazard
The Bunsen burner is a hazard because it has inherently harmful properties — an open flame that can cause burns.
Point 2: define the riskRisk is the level of danger the hazard poses, which depends on the likelihood of harm and its severity.
Point 3: apply it
If the burner is used on a clear bench, with hair tied back and the flame on yellow when not in use, harm becomes unlikely, so the risk is low even though the hazard is unchanged.
The hazard is fixed; the risk is what your precautions changethis exact distinction is worth a mark on its own in many mark schemes.
💡 Exam tips
Structure every safety answer as hazard → precaution → justification.
Say whether your precaution reduces the likelihood or the severity of harm. It reads as real evaluation.
Never write “wear a lab coat and goggles” as your whole answer — it is assumed in any laboratory.
For ethics with animals, quote the principle: only if no alternative exists, never cruel, and remove causes of distress.
For humans, the phrase you want is fully informed consent.
Environmental points split cleanly into lab disposal and field impact. Pick the one that fits the practical described.
⚠ Common mistakes
Using hazard and risk as synonyms. They are separate ideas and questions test the difference directly.
Giving a generic precaution. If your sentence would fit any practical in the course, it is too generic.
Writing “be careful” as a control measure. A control measure is a change to the method.
Confusing ethical with environmental. Ethics concerns the treatment of living organisms and participants; environmental concerns impact on the habitat and waste.
Forgetting consent is “informed”. Agreeing without knowing what will happen is not consent.
Up next: Measuring Variables. Once your procedure is safe, the next question is whether the numbers it produces are any good. That means choosing the right instrument, knowing its precision, and being honest about the uncertainty in your readings.
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