Science labs are perhaps the most dangerous place in a high school, but they’re also indispensable if a hands-on education is to be provided. This makes it imperative that safety precautions are carefully followed when designing the lab, storing chemicals/apparatus, and also when the actual experiments are being conducted.
Since high school science labs are typically populated by young men and women with little or no experience in handling chemicals, it is equally necessary that safety precautions are carefully explained. This small guide is therefore aimed at explaining the most vital safety precautions and procedures.
To begin with, the location of the labs: Common sense says that maximum use of chemicals and gases (whether for experiments or as fuel) is in the chemistry lab. Indeed, many chemistry labs have to maintain a steady supply of combustible gas to fuel the Bunsen burners, etc. Naturally, this increases the fire risks associated with this lab. Therefore, it is advisable to place it on the ground floor, preferably in a separate wing, or if that’s not practical, at the end of the corridor. If there’s a three-storied building, the biology lab (with lesser chemicals but greater use of microbes) above, and the physics lab at the top. However, it is more advisable if all labs can be placed as close to the ground as possible.
All labs must be sufficiently ventilated and the work space should be as close to the exit as possible. Access to fire-control apparatus and wash basins must also be ensured. The teacher’s station/desk must be placed such that it is clearly visible from even the most distant workbench, so that students do not crowd around the teacher during demonstration. Finally, adequate provision for natural light, especially in biology and physics labs, is required.
After location comes storage and handling chemicals and microbes. Again these pertain most to the chemistry lab. Here, sources of gas supply (pipes, cylinders) should be placed away from the storage area of chemicals, and also the work space.
The work space itself should be open and contain no more than the most common and harmless of chemicals. Others, especially corrosive alkali ,acids and gases, must be stored elsewhere and provided by the lab assistant concerned. It is advisable if the chemicals provided are prediluted, unless the experiment requires that the students carry it out themselves.
Similarly for biology lab, all specimens are to be properly stored, while in Physics lab, the precision instruments should be kept away, and provided only when needed.
Students themselves must be aware of proper lab procedures, and for this adequate instructions must be given prior to lab work. Drinking and eating in the lab must be strictly prohibited. It is advisable to avoid loose-fitting garments, like jackets, ties, etc. Protective gear, including lab coats, goggles and gloves should be kept ready at all times.
Apparatus must be kept ready before the students enter the lab, if needed at the workstations themselves. Extensive shifting of heavy/delicate apparatus like microscopes, should be avoided. Once the students enter, they must proceed to their allotted workstations, individually or in groups as need be. Thereafter, the teacher should clearly repeat instructions and proceed with demonstration. This done, she should clearly indicate which chemicals/samples/apparatus to use, and what precautions to take.
For chemistry lab, these would include proper instructions on handling chemicals, glass apparatus and open flame. Flammable and non-flammable chemicals must be kept apart, and the former (like acetone) away from the flame. Proper procedure regarding dilution of acids, cooling of hot solutions, etc should be taught before experiments involving them are carried out. Students under no circumstances should smell/observe the chemical by bringing their face close to the test tube. In case an experiment goes awry, the work space must be immediately abandoned, till such time as deemed safe by the teacher.
Glass apparatus must be treated with especial care, beginning with cleaning it out thoroughly, and then drying it before conducting the experiment. Bunsen burners must never be lighted until they’re required. They should never be left unattended. On the other hand, temperature must never be tested by touching – a thermometer should be used. Finally, reagents left over in test tubes after the experiments are over must never be returned to their original containers.
In biology lab the required specimens should be handled like they are pathogenic. This includes using gloves where needed, and washing hands before and after the experiment. Here too, proper techniques of slide-making, mounting, observation and reportage should be explained before commencing.
In physics lab, batteries containing acids should be handled carefully, making sure they do not tilt or fall sideways. Sharp instruments, including glass and metal apparatus, should be carefully handled. If the experiments involve electricity, apparatus should be kept away from water.
Finally, it is always important to dispose of the used chemicals, samples and/or apparatus carefully. To this end, sufficient bins of sturdy and chemical-resistant nature must be provided. Students must be warned not to scoop up spilled chemicals, but to seek help in disposing them. Similarly, broken apparatus, especially glass apparatus, must not be handled by hand, but swept away into the bin. Used chemicals/biological samples are to be carefully poured out as per their properties, and disposed. All re-usable apparatus must be washed before the next experiment.
If these procedures are duly followed, the true learning educational potential of the experiments can be unlocked, and they can be not just safe, but fun as well.