Assessing Hazards and Risks
Evaluate risks before and during practical work: identify hazards (a substance, flame or procedure that could cause harm), judge how likely and how serious the harm would be, and choose sensible control measures to reduce the risk
What a learner can do afterwards
- Identify the hazards in a planned experiment (e.g., acid can burn skin, a beaker of hot water can scald)
- Distinguish a hazard from a risk, judging the risk by how likely harm is and how serious it would be
- Choose sensible precautions for an experiment (e.g., wear goggles, tie hair back, heat gently, use a smaller amount)
The lesson
Every experiment has hazards. A hazard is anything that could cause harm: a flame, a sharp blade, a hot beaker, an acid. Having a hazard in the room does not mean the experiment is too dangerous to try.
A risk is different from a hazard. To judge a risk, ask two questions: how likely is it that harm happens, and how bad would it be if it did? A candle flame is a hazard whether you touch it for one second or ten, but holding your hand there for ten seconds is a much bigger risk.
Priya plans to heat vinegar in a test tube over a candle. She spots the hazard: hot glass and steam could burn her hand. She judges the risk as fairly likely if she is careless, and a burn would hurt. So she picks a precaution: she holds the tube with tongs and points the open end away from her face.
Before you start any experiment, ask three questions: what could go wrong, how likely and how bad is that, and what one change makes it safer.
Spot the hazard, weigh how likely and how serious the harm could be, then choose one sensible precaution before you start.
Watch it
Where it sits
Learn first
This opens up
Nothing builds on it yet.
Where this leads
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.