Science Instruction and Laboratory Safety
Laboratory safety
Safety is part of instruction, not an afterthought. Know the SDS for every chemical, use PPE (goggles, gloves, apron), and follow a written safety contract. Never taste or mouth-pipette chemicals; waft odors. Add acid to water, not water to acid, and add slowly with stirring. Keep flames away from flammables; know the location of the eyewash, safety shower, fire extinguisher, and spill kit. Dispose of waste in labeled containers-never down the sink unless the instructor confirms it is allowed. Report all spills and injuries immediately.
Teaching and assessment
Inquiry labs should state a question, variables, procedure, safety review, and data analysis. Use formative checks before labs and assess both content and practices. Differentiate roles so every student handles equipment. Model safe behavior and enforce rules consistently.
Worked example
To prepare 100 mL of 0.10 M HCl from 1.0 M stock, use M1V1 = M2V2: V1 = (0.10 M)(100 mL)/(1.0 M) = 10 mL. Add about 50 mL of water to a beaker, slowly add 10 mL of acid with stirring, then dilute to 100 mL. Acid goes into water, and goggles/gloves are worn throughout.
Traps
Adding water to concentrated acid; storing acids with bases; using a sink for every waste; skipping goggles for quick steps; and treating safety as a list to memorize rather than a procedure to rehearse.