Running Safe, Successful Chemistry Practicals

A good practical lesson can be the moment a student decides they love chemistry. A poor one can be forty minutes of confusion, spilled acid and a results table full of guesses. The difference is rarely the experiment itself; it’s the planning, routines and questioning around it. This guide collects practical advice for teachers, especially those early in their careers or teaching outside their specialism.

1. Decide what the practical is for

Before planning anything, write down the purpose in one sentence. Practicals serve different goals, and the lesson structure depends on which one you choose:

Purpose	Example	What students should focus on
Seeing a phenomenon	a flame test, a displacement reaction	careful observation and description
Learning a technique	using a burette	correct procedure and why each step matters
Testing an idea	does temperature affect rate?	variables, fair testing, conclusions
Collecting data to process	enthalpy of neutralisation	accuracy, recording, calculations

Trying to achieve all four at once usually achieves none. A technique-focused lesson doesn’t need a complex investigation attached to it.

2. Always trial the practical

Do the experiment yourself before the lesson, ideally with the same batch of chemicals and equipment students will use. Trialling reveals:

• solutions that are the wrong concentration or have degraded (hydrogen peroxide and some indicators lose strength)
• timings that are much longer than the method suggests
• steps students will find confusing
• what the results actually look like, including typical “wrong” results

If you have a technician, discuss the trial with them. They often know exactly where things go wrong.

3. Work with your technician

Technicians are expert partners, not a delivery service. Help them help you:

• submit requisitions early and completely: quantities per group, concentrations, number of groups
• specify any hazard information and disposal needs
• ask their advice on alternatives if something’s unavailable
• say thank you, and give feedback on what worked

4. Risk assessment

Every practical needs a risk assessment, usually based on the model assessments your school uses (many countries have national advisory services that publish these). Check:

• the hazards of every substance, including products (see hazard symbols)
• the concentrations and volumes actually needed; use the lowest that works
• specific controls: eye protection type, fume cupboard, heat source
• your class: size, behaviour, space, any additional needs
• disposal of every product

Ask students to write a short risk assessment themselves for suitable practicals. See risk assessment in chemistry for a student-facing guide you can share.

Reduce the scale where you can. Microscale techniques such as spotting plates and dropper bottles reduce hazards, waste and cost, and often speed up the practical.

5. Establish routines

Routines free students’ attention for the chemistry. Teach them explicitly, and repeat them every lesson until they’re automatic:

• Entering the lab: bags away from walkways, stools under benches, eye protection on before anything is uncovered.
• Collecting equipment: one named person per group, from a clearly laid-out station.
• Stop signal: a clear signal (a raised hand, a bell) at which everyone stops, puts down equipment and looks at you.
• Spills and breakages: tell the teacher immediately; never clear up broken glass by hand.
• Clearing away: a set time before the end of the lesson, with a clear checklist.

Display the lab safety rules and refer to them.

6. Before hands-on: prepare minds

Students who understand what they’re about to do work more safely and learn more. Useful approaches:

• Demonstrate the key technique at the front, including common mistakes (“watch what happens if I read the burette from above”).
• Pre-lab questions: two or three short questions students must answer before starting, such as What is the hazard of this chemical? What will you measure? What do you predict will happen?
• Visual methods: a numbered flowchart or photos of each step beats a dense paragraph of instructions.
• Check understanding by asking one student to explain the next step to the class.

7. During the practical: keep them thinking

The biggest risk in practical work is that students follow instructions like a recipe without thinking about the chemistry. Circulate and ask questions:

• Why are you adding it drop by drop now?
• What does that colour change tell you?
• Is this result what you expected? Why or why not?
• If you did this again, what would you change?

Short prompts on each bench (“While you wait: explain why the water bath is used”) make good use of waiting time.

8. Plan for things going wrong

• Keep spare results (from your trial) so groups whose experiment fails can still do the analysis.
• Have an extension ready for fast groups: a second concentration, a prediction question or an evaluation task.
• Leave enough time to clear up without rushing. Rushed clearing is when accidents happen.

9. After the practical: make sense of it

The learning is often in the follow-up rather than the experiment itself.

• Pool class results on the board. Discuss the spread, identify anomalies and ask why they happened. See experimental errors.
• Link to theory explicitly: “What does this tell us about the reactivity series?”
• Graphs and calculations: model one on the board before students do their own. See graphs in chemistry.
• Evaluation: ask for specific improvements linked to specific errors.
• Write-ups: not every practical needs a full report, but some should. See writing a lab report.

10. Build skills across the year

Plan practical skills as a progression, not a list of isolated experiments:

• Early: safe behaviour, observation, simple measurement.
• Next: accurate measurement, tables and graphs.
• Then: fair tests, variables and repeatability.
• Later: planning investigations, evaluating uncertainty and choosing methods.

A practical skills checklist shared with students helps them track progress too.

Common pitfalls for new teachers

• Too many instructions at once. Give the first few steps, check, then give the next.
• Handing out equipment before explaining. Students start fiddling instead of listening.
• Standing at the front. Circulating lets you spot problems early and ask better questions.
• No time for the chemistry. If the practical runs long, cut the write-up, not the discussion of what the results mean.

A one-page lesson plan template

1. Purpose (one sentence).
2. Safety: hazards, controls, disposal.
3. Starter: pre-lab question or prediction.
4. Demonstration of key technique (5 minutes).
5. Hands-on work with thinking prompts.
6. Clear-up (start at least 10 minutes before the end).
7. Plenary: pool results and link to theory.
8. Follow-up: calculation, graph or evaluation task.

Key takeaways

• Decide the purpose of each practical and focus the lesson on it.
• Always trial the experiment and work closely with your technician.
• Risk-assess every practical, use minimum quantities and consider microscale.
• Explicit routines make labs safer and free students to think.
• Prepare students before they start, question them during, and make sense of the results afterwards.