Lab safety and equipment

A science lab has hazards: heat, flames, glass and chemicals. Knowing the hazard symbols, the names of the apparatus and a few safe habits means practical work can be done safely.

Key facts

  • A hazard is something that could cause harm; the risk is the chance that it does. A control measure makes the risk smaller.
  • Hazard symbols are a black picture in a red diamond: a flame means flammable; a hand and a surface being eaten away mean corrosive; a skull and crossbones means toxic; an exclamation mark means harmful or irritant; a flame over a circle means oxidising.
  • Always wear safety goggles, tie long hair back, stand up, keep bags under the bench, keep the bench tidy, and never eat or drink.
  • Heat a test tube gently, pointing it away from everyone. Use tongs for hot things. Tell the teacher about every spill or breakage.
  • Bunsen burner: air hole closed gives the yellow safety flame (easy to see); air hole open gives the blue roaring flame (the hottest).
  • Common apparatus: beaker, test tube, conical flask, measuring cylinder, tripod and gauze, heatproof mat, clamp stand, evaporating basin, funnel and filter paper, spatula.

Worked examples

Example 1

How do you light a Bunsen burner safely?

  1. Put on safety goggles. Stand the burner on a heatproof mat, with the hose straight.
  2. Close the air hole, so it lights with the yellow safety flame.
  3. Light a splint, turn on the gas and hold the splint just above the top of the chimney.
  4. Open the air hole for a hotter blue flame. Close it again (yellow flame) whenever you are not heating.

Answer: goggles on, burner on a heatproof mat, air hole closed, light a splint, turn on the gas and light the burner, then open the air hole as needed

Example 2

A bottle of acid has this hazard symbol. What does it mean, and what precautions should you take?

  1. The picture shows liquid dripping onto a hand and a surface and eating into them: corrosive.
  2. Protect your eyes and skin: wear safety goggles; use the most dilute acid and the smallest amount that works.
  3. If it touches your skin, wash it off with plenty of cold running water and tell the teacher.

Answer: it is corrosive: it destroys skin and materials; wear goggles, use small amounts of dilute acid, wash any spill off with lots of cold water and tell the teacher

Example 3

Name the apparatus used to heat water in a beaker over a Bunsen burner.

  1. A heatproof mat protects the bench.
  2. A tripod stands over the Bunsen burner, with a gauze on top to spread the heat.
  3. The beaker of water sits on the gauze.

Answer: a tripod and gauze on a heatproof mat, with the Bunsen burner underneath

Example 4

Write one line of a risk assessment for heating a liquid in a test tube.

  1. Hazard: what could cause harm? Hot liquid that can spit out of the tube.
  2. Risk: what harm, and how likely? Burns to the skin or eyes.
  3. Control measures: heat gently while moving the tube, point it away from everyone, hold it with a test-tube holder and wear goggles.

Answer: hazard: hot liquid spitting out; risk: burns to skin or eyes; control: heat gently, point the tube away from people, use a test-tube holder and wear goggles