Last reviewed: 12 November 2026
Updated November 2026. These Grade 7 laboratory safety notes cover the common hazard symbols, the accidents that happen most often in a school laboratory, first aid for each one, and the safety rules every learner should follow. In short: a flame symbol means flammable, a symbol of liquid eating into a hand and a surface means corrosive, and a skull and crossbones means toxic. For a burn or scald, cool the area under clean running water and tell the teacher at once.
These are original revision notes for Kenyan junior school learners. They follow the Laboratory Safety sub-strand of Scientific Investigation in the Grade 7 Integrated Science design, listed on the KICD curriculum designs page. The apparatus itself is covered in our Grade 7 laboratory apparatus notes, and the whole year is summarised in the Grade 7 Integrated Science revision guide.
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Common Hazards and Their Symbols
A hazard is anything that can cause harm. Containers of chemicals carry warning symbols so that anyone can recognise the danger without reading a long label. The flame, corrosion, skull and crossbones and health hazard symbols are internationally agreed chemical pictograms, which you can view on the OSHA hazard communication pictograms page. The radioactive trefoil is a separate international warning sign. The five hazards the design names are:
- Flammable: a flame. The substance catches fire easily. Examples: methylated spirit, paraffin, ethanol.
- Corrosive: liquid dripping onto a hand and onto a surface, both being eaten away. The substance destroys skin and materials. Examples: concentrated acids and strong alkalis.
- Toxic: a skull and crossbones. The substance can poison you if swallowed, breathed in or absorbed through the skin. Example: mercury compounds.
- Carcinogenic: a person’s outline with a star-shaped mark on the chest (the health hazard symbol). Long exposure can cause cancer.
- Radioactive: a black trefoil (three blades round a dot) on a yellow background. The substance gives off radiation.
Common Laboratory Accidents and First Aid
The design asks learners to explain the causes of three kinds of accident and the first aid for each.
Burns and scalds
A burn comes from dry heat, such as touching a hot tripod or a Bunsen flame. A scald comes from hot liquid or steam, such as a boiling test tube pointed at someone. First aid: cool the area under clean, cool running water for several minutes, remove tight items such as rings if the area may swell, cover loosely with a clean non-fluffy cloth, and report to the teacher. Do not apply butter, oil or toothpaste.
Cuts
Cuts usually come from broken glassware or careless use of a scalpel. First aid: press a clean cloth on the wound to stop the bleeding, raise the injured part if possible, and let the teacher remove any glass. Never pick up broken glass with bare hands; sweep it into the broken-glass bin.
Swallowing harmful substances
This happens when someone eats or drinks in the laboratory, or uses the mouth to suck liquid into a pipette. First aid: tell the teacher immediately, rinse the mouth with water, do not make the person vomit unless a health worker says so, and take the chemical container to the health worker so they know what was swallowed.
Safety Measures in the Laboratory
- Enter only when the teacher is present and follow instructions.
- Wear a lab coat and safety goggles when heating or handling chemicals; tie back long hair.
- Never eat, drink or taste anything in the laboratory.
- Read the label and hazard symbol before using any chemical.
- Point the mouth of a test tube away from yourself and others when heating.
- Know where the fire extinguisher, sand bucket, first aid kit and exits are.
- Report every accident or breakage, however small.
- Wash your hands and clean the bench before leaving.
Original Practice Questions With Worked Answers
- A bottle shows a flame symbol. What does it mean and how should it be stored? Flammable: it catches fire easily, so keep it closed and away from flames and heat.
- Distinguish between a burn and a scald. A burn is caused by dry heat; a scald by hot liquid or steam.
- Give two causes of cuts in the laboratory. Handling broken glassware; careless use of sharp tools such as scalpels.
- State the first aid for a scald on the hand. Cool under clean running water for several minutes, cover loosely with a clean cloth and report to the teacher.
- Why should learners never eat in the laboratory? Food can pick up harmful chemicals from hands or benches and be swallowed.
- Name the hazard shown by a skull and crossbones. Toxic (poisonous).
Test yourself further in the Grade 7 CBC Challenge. These notes are free; full revision access, including practice papers, comes with the KSh 20 Day Pass or the KSh 500 Monthly Pass. Free calculators and other revision aids are on the CBC Guides tools page.
Frequently Asked Questions
What are the five hazard symbols in Grade 7 Integrated Science?
Flammable, corrosive, toxic, carcinogenic and radioactive. Each has its own pictogram so the danger can be recognised quickly.
What is the first aid for a burn in the laboratory?
Cool the burn under clean, cool running water for several minutes, cover it loosely with a clean cloth and report it to the teacher. Do not apply oil or butter.
What should you do if a classmate swallows a chemical?
Tell the teacher at once, rinse the mouth with water, do not force vomiting, and take the chemical container to the health worker.
Why is it important to report every laboratory accident?
Some injuries, such as chemical splashes, get worse without proper treatment, and reporting lets the teacher remove the cause so that nobody else is hurt.