Lab safety for Scientific Experiments

 

Lab safety in a necessity because Laboratories are delicate places. Carelessness in there can cause serious accidents.

Care in the laboratory

The two most important words to remember when working in a lab are “Be CAUTIOUS and LABORATORY WORK DONE WITHOUT ENOUGH CARE TURNS TO BE UNWORTHY”.

–          Familiarity with materials and equipment being used is important

–          Safety equipment like fire extinguishers and first aid kits must be placed where they can be easily located and picked for use in case of accidents

–          Ignorance and negligence are two of the major causes of accidents in the laboratory

–          Follow the instructions given to you and do all your experiments with utmost precautions

RULES OF DISCIPLINE IN THE LABORATORY

1.       Do not enter the laboratory unless you are instructed to do so;

2.       Never run or chase each other in the laboratory;

3.       Do not leave any object in the passage ways or the floor

4.       Never taste any of the chemicals found in the laboratory

5.       Never eat or drink anything in the laboratory

6.       Do not leave the table or the apparatus untidy. Always clean them and return the apparatus to their proper places;

7.       Do not hesitate to seek advice where you are not sure;

8.       Do not fail to report any accidents, however small, that occur

9.       Do not perform any lab work until you have been briefed.

10.   Do not enter instructor stations or the Stockroom unless asked to do so by the staff.

SAFETY RULES IN THE LABORATORY

A physics laboratory is a place where discovery leads to knowledge and understanding. It is also a place where caution is essential for your safety and safety of others. Your knowledge of and adherence to safe laboratory practices are important factors in avoiding accidents. The following information describes some basic and general rules for safe laboratory work. Read the rules thoroughly and observe them in the laboratory.

1.       Locate and learn to use all laboratory equipment.

2.       Never eat, drink, chew gum, or apply cosmetics in the laboratory. Do not store food or beverages in the laboratory.

3.       Never do a lab investigation without your teacher’s supervision (Here investigation is different from experiment).

4.       Never run, push, or fool around in the laboratory.

5.       Keep your work area clean and uncluttered. Store items such as books and purses in designated areas. Keep glassware and containers of chemicals away from the edges of your lab bench.

6.       Turn off all electric equipment, water and gas when not in use.

7.       Pay attention to safety cautions. Wear safety goggles and lab apron whenever you use heat, chemicals, solutions, glassware or other dangerous materials.

8.       Dress properly for the laboratory. Do not wear loose-fitting sleeves, bulky outerwear, dangling jewellery or open-toed shoes. Tie back long hair and tuck in scarves when you use heat or chemicals.

9.       Never touch a hot object with your bare hands. Use a clamp, tongs or heat-resistant gloves when handling hot objects.

10.   In the event that your hair or clothing catches fire, DO NOT RUN, for this will fuel the fire. Rather, STOP – DROP – ROLL to smother the fire. Help to smother any fire on a co-worker with your apron or lab coat (soaked in water), or with your own body.

Apart from these general safety rules, there are more other rules for specific type of experiment you will perform in the laboratory.

EXPERIMENTS INVOLVING HEAT

Three main sources of heat that may be available in the laboratory are: Bunsen burner, spirit lamps and electric hot plates.

They present dangers such as fires explosion, burns and scalds. To avoid the dangers, the techniques below are to be followed:

1.       If the substance to be heated in a test is a solid, slant the test tube in such a way that the substance is spread out and does not block the test tube;

2.       When heating a liquid in a test tube:

a.       The test tube must not be more than a quarter full

b.       Use a wide boiling tube and keep shaking it gently all the time

c.       Use a gentle flame to avoid rapid boiling

FIGHTING THE FIRE

In case of fire in the lab, observe the following:

Fight a fire ONLY if ALL of the following are TRUE

·         Everyone has left, or is leaving the lab.

·         Public Safety has been called (911).

·         The fire is very small and confined. (If the fire is in a beaker or a wastebasket, try to smother it by covering the container. Often, this works quite well and does not require the use of a Fire Extinguisher.)

·         You have a way out and you can fight the fire with your back to the Exit.

·         The extinguisher is rated for the class of fire you are fighting.

·         You can stay close to the floor to avoid breathing too much of the smoke.

·         You have had training and you feel confident in the use of the extinguisher, or no other escape alternative is available to you.

It is usually best to have the teacher or lab assistant operate a fire extinguisher if one is needed at all. Much damage can be done by the improper use of a fire extinguisher.

When you are ready to use the extinguisher

What do you do? The key word to operating a fire extinguisher is PASS. This acronym is a good way to remember exactly what to do.

·         PULL the pin. Point the nozzle away from you and release the locking mechanism.

·         AIM low. Hold the extinguisher upright. Aim at the base of the flame. You should be 2 to 3 metres away. If you are too close, you will hit the fire with enough force to scatter it. If you are too far away, you may not reach the fire with enough extinguishing material.

·         SQUEEZE the trigger. Be prepared. The extinguishing agent may come out with considerable force and noise. Most portable extinguishers will last for only 15 to 30 seconds. That is the actual “fighting time” you have. You can prolong the effective fighting time if you use short bursts. If aimed well, they can be very effective.

·         SWEEP side-to-side. Drive the fire back. As you extinguish the fire closest to you, move forward, but continue the sweeping motion.

Once the fire is out, you should have your teacher and the lab assistant check on the area. They will assume the responsibility of following up the incident with the appropriate authorities i.e. if necessary. This will include making certain that all persons are out of the area, insuring that another fire extinguisher is nearby in the event of a recurrence of the fire, and making arrangements to replenish the spent extinguisher. Remember you will probably NOT need to use a fire extinguisher at all in your physics laboratory.

Abandon the Fight if ANY of the following are TRUE

• The fire has started to spread.
• Your escape route may be blocked.
• You have any trouble operating the extinguisher.

As you leave the lab, close the door to prevent spread of the fire and call 911 to be sure help is on the way. Then leave the building and wait in the designated area for help to arrive. (Remember that everyone must be accounted for at the meeting place BEFORE leaving that area. Anyone not found at the meeting area will be presumed trapped inside and someone will attempt a rescue).

GAS CYLINDERS

The pressure of the gas in these cylinders is very high, sometimes up to 150 atmospheres. If the gas contained in the cylinder is released suddenly it may present a hazard. Never interfere with the gas taps, never roll any cylinder about freely and always store all cylinders in a cool place.

MAINS ELECTRICITY

–          Never interfere with electrical fittings and never use equipment with exposed main connectors

–          Touching a bare live wire may get you a nasty electric shock.

–          Do not stand on a wet floor with bare feet

–          In case of electric shock, the source of the current should be disconnected immediately.

–          If the accident victim stops breathing it is crucial that you apply artificial respiration quickly

–          All equipment with metallic casing should be earthed.

RADIATION HAZARDS

Radioactive sources used in school laboratories are usually very weak but it is still important that you take care when handling them:

1.       Never point a source of radioactivity at another person

2.       Keep as far from the source as possible to minimise exposure

3.       Handle a radioactive substance with forceps

4.       Wear rubber gloves when using radioactive sources and wash your hands afterwards

5.       Shield the sources with lead bricks

Some of the effects of over exposure to radiations are:

a.     Un-healable burns

b.     Sterility

c.     Cancer of the blood(leukaemia)

d.     Lowered resistance to diseases

e.     Sometimes children of parents who have been exposed to radiation are born with abnormalities

MERCURY

Mercury which is used in thermometers, manometers and barometers, is a poisonous liquid. All containers of mercury should be closed and any of it that spills should be cleaned up.