1. The place where a scientist works is called a laboratory.
2. Students carry out scientific investigations or experiments during science lessons in science laboratories.
3. There are many apparatus and chemicals in the science laboratories. These may cause accidents when not handled properly.
4. So, students need to follow the rules and safety precautions when they enter and use the science laboratory.
Rules and safety precautions in the laboratory
1. No student is allowed to enter the laboratory without the teacher's permission.
2. Eating and drinking are not allowed in the laboratory.
3. Apparatus and chemicals must not be taken out of the laboratory.
4. Do not run or play in the laboratory.
5. Do not touch any chemical with bare hands. Use a spatula.
6. Read the label on a reagent bottle before using its content.
7. D not waste any chemical. Use only the required amount.
8. Do not pour back any unused chemical into its bottle.
9. Do not taste or test any chemical without the teacher's permission.
10. Solid wastes must be disposed of in the bins provided. Do not throw solid wastes into the sink.
11. Report any breakages or any accidents such as burns, cuts or swallowing of chemicals to the teacher at once.
12. Clean and keep all apparatus in their correct places after use.
13. The bench must be left clean and tidy.
14. Wash your hands thoroughly before leaving the laboratory.
Common laboratory apparatus
There are many apparatus in the science laboratory. We must use the correct apparatus for each job during an investigation.
Using a Bunsen burner
1. A Bunsen burner is used in the laboratory for heating substances.
2. The correct way to light up a Bunsen burner :
(a) Close the air-hole by turning the collar.
(b) Bring a lighted matchstick or lighter near the mouth of the barrel.
(c) Turn on the gas slowly. A yellow flame will be obtained.
(d) Open the air-hole slowly to obtain a blue flame.
3. The size of the air-hole determines the type of flame produced.
4. When the air-hole is closed, a yellow flame is produced. This flame is easier to see and is called a luminous flame. It is less hot and produces a lot of black soot. Thus, it is not suitable for heating.
5. When the air-hole is opened, a blue flame or non-luminous flame is produced. This flame is much hotter and is suitable for heating.
6. Safety precautions while using a Bunsen burner :
(a) Use a lighted matchstick or lighter to light up a Bunsen burner instead of a burning piece of paper.
(b) Light up the lighter before turning on the gas.
(c) When heating a test tube, hold the tube at an angle of 45°. Keep moving the test tube in and out of the flame and shake the test tube gently to avoid overheating. Do not point the mouth of the tube to anybody.
(d) Do not heat flammable substances like alcohol directly. Use a water bath instead.
(e) When not using the Bunsen burner temporarily, close the air-hole to obtain a yellow flame because this flame is easily seen.
(f) Remember to turn off the Bunsen burner after use.
Hazard warning symbols
1. Some substances in the laboratory are hazardous or dangerous if not handled properly.
2. Hazard warning symbols are placed on the labels of their danger.
3. As young scientists, you must be able to recognise the symbols and know how to handle the substances properly.