Every experiment you do in physics comes with a responsibility — to yourself, to others, and to the world around you. Before you switch on a laser or heat a flask of water, you need to think about three things: is it safe, is it ethical, and what’s its environmental impact? Examiners love to test this, and it’s genuinely useful in the lab. Here’s how to identify the risks and show you can manage them properly.
📚 What you need to know
A risk assessment should identify hazards, assess the risk, and minimise it
A hazard is something that could cause harm; the risk is how likely and severe that harm is
Different apparatus has different hazards: radioactive sources, lasers, high voltages, hot water, pressurised glass
Physics has few ethical issues, but consider consent (human subjects) and animal welfare
If there’s no ethical concern, you can say so — but justify why
Environmental impacts include electricity use, water use, and battery disposal
If you find an environmental concern, you must explain how you’ll reduce it
Safety: identify, assess, minimise
Whenever you carry out an investigation, you must identify the safety hazards and risks, and manage them. A good risk assessment always follows the same three moves:
A risk assessment isn’t a list of dangers — it’s these three actions: spot the hazard, judge the risk, then change what you do to reduce it.
Here’s the distinction examiners want you to nail: a hazard is the thing that could hurt you (a hot beaker, a laser beam), while the risk is how likely it is to actually cause harm and how bad it would be. A sharp knife locked in a drawer is a hazard with low risk. Get that difference clear and you’ll pick up the easy marks.
Hazards of common apparatus
Different equipment brings different dangers. Here are the ones you’re most likely to be asked about, and how to handle each safely.
Apparatus
Main hazard
How to minimise the risk
Radioactive sources
Ionising radiation
Store in lead-lined, labelled boxes; handle with tongs; never point at anyone; use for the shortest time; keep students at a distance
Lasers
Eye damage
Never aim at people or reflective surfaces; keep the beam horizontal and below eye level; wear laser goggles; switch off when done
Electron diffraction
High voltage
Only qualified staff set it up; ensure it’s earthed; never touch live connections
Hot water / gas experiments
Burns, scalds
Keep apparatus away from table edges; never leave unattended; don’t sit beside beakers of hot water
Pressurised glass (Boyle’s law)
Explosion, breakage
Shield glass tubes with clear screens; don’t overfill gas syringes; handle carefully
Electrical circuits
Shock
Use low voltages (1.5–9 V); check mains equipment is earthed; avoid bare wires and water nearby
And the general rules that apply almost everywhere: wear goggles and gloves when handling hot equipment, glass or chemicals, and handle glassware carefully to avoid breakage.
Ethical issues
Physics rarely raises the big ethical concerns you’d meet in biology or psychology — but you should still think it through. Ask whether your equipment or methods could pose an ethical dilemma:
If your investigation involves human subjects, you must obtain their consent.
If it involves animals, you must follow proper ethical guidelines and protocols.
If you genuinely can’t identify any ethical concern, it’s fine to say so — but you must justify why there isn’t one, rather than just ignoring the question.
Environmental issues
Most physics experiments have a low environmental impact, but “low” isn’t “none”. The three big ones to consider are electricity, water, and batteries.
The three most common environmental concerns in a physics lab — each with the “good practice” that reduces its impact.
Beyond these, the golden rule is waste reduction: wherever possible, reuse or recycle materials rather than discarding them, and follow proper disposal methods. And crucially — if you identify an environmental concern in an investigation, you must explain how you intend to reduce it. Spotting the problem isn’t enough; you need the solution too.
Identify a concern
safety / ethics / env.
Explain the impact
state your plan
Reduce or manage it
WE 1
A student plans an experiment using a laser to investigate diffraction. Identify one hazard, assess the risk, and suggest how to minimise it.
Step 1 — identify the hazard
The laser beam could cause eye damage.
Step 2 — assess the risk
Serious harm (permanent eye injury), likely if the beam reaches an eye directly or by reflection.
Step 3 — minimise
Keep the beam horizontal and below eye level, never aim at people or shiny surfaces, wear laser goggles, and switch off when finished.
Hazard: eye damage → minimise with beam control + gogglesAlways give all three parts: the hazard (the thing), the risk (how bad/likely), and a specific control measure. A vague “be careful” scores nothing.
WE 2
An experiment repeatedly uses fresh water in a ripple tank and runs mains-powered lamps for several hours. Identify two environmental concerns and state how to reduce each.
Concern 1 — water use
Using fresh water each time is wasteful. Reuse the same water across trials and dispose of it properly.
Concern 2 — electricity use
Mains power often comes from fossil fuels. Switch lamps off when not in use and choose energy-efficient equipment.
Reuse water; switch off / use efficient lampsFor every environmental concern you name, you must pair it with a way to reduce it. Identifying alone won’t earn full marks — the reduction plan is the point.
⚛ Answering a “safety/ethics/environment” question
Hazard: name the specific thing that could cause harm.
Environment: name the concern and your plan to reduce it.
💡 Top tips
Hazard = the thing; risk = how likely/severe the harm.
Always pair a hazard with a specific control measure.
For ethics, mention consent or animal welfare, or justify their absence.
Environmental answers need a reduction plan, not just the concern.
“Be careful” scores nothing — be specific.
⚠ Common mistakes
Confusing a hazard with a risk
Writing vague controls like “be careful” instead of specific actions
Naming an environmental concern but not saying how to reduce it
Ignoring the ethics part instead of justifying “no concern”
Forgetting apparatus-specific rules (tongs for sources, goggles for lasers)
Quick recap: A risk assessment means identify the hazard, assess the risk, and minimise it with a specific control. Know the hazards of radioactive sources, lasers, high voltages, hot water and pressurised glass. For ethics, consider consent and animal welfare (or justify none). For the environment, address electricity, water and batteries — and always pair a concern with a plan to reduce it.
Working safely is the first practical skill — the second is measuring accurately. An experiment is only as good as its data, and that means picking the right instrument and reading it correctly. Next page: Measuring Variables.
Practical safety questions catching you out?
Book a free meeting and we’ll drill the hazard-vs-risk distinction, apparatus-specific controls, and the ethics and environment points examiners reward.
