TOPIC 2: INTRODUCTION TO LABORATORY PRACTICE
A laboratory is a room or a building designed specifically for carrying out experiments.
Laboratory Rules and Safety Guidelines
Rules in a Physics Laboratory
While working in the lab, individuals are advised to adhere to specific lab rules to ensure their safety, the safety of others working in the lab, and the safety of the apparatus and chemicals stored in the lab.
Rules in the physics lab
- You should only enter the lab in the presence of a lab attendant.
- Keep all exits and entrances to and from the lab clear of obstructions.
- Don’t eat or drink in the lab.
- Solid objects should not be thrown into the sink or waterways.
- Don’t use any lab container for drinking or storing food.
- Make sure that you wash your hands with soap before you leave the lab.
- The cover or stopper of a particular chemical must be replaced immediately after use.
- After experiments, clean your bench and leave it dry and well arranged.
- Never quarrel or fight in the lab.
- Never use ungloved hands to hold hot objects.
Safety Measures in the Physics Laboratory
Explain the safety measures in physics laboratory
Safety measures in physics lab
- All experiments which produce poisonous fumes must be conducted in the fume chamber.
- Lab floor should not be polished to avoid slipperiness.
- Lab should have large windows and doors should be opened outwards.
- Ensure that the fire extinguisher is fixed to an appropriate place ready to be accessed in case of fire.
- In a multi-storey building, a physics lab should be on the lowest floor.
Using First Aid Kit to Render First Aid
Use the First Aid Kit to render first aid
First aid
First aid is the immediate care given to accident victims or an injured person before he/she is taken to the hospital for further medical treatment. It reduces pain and helps to bring hope and encouragement to accident victims.
A First Aid Kit
A First Aid Kit is a small box placed in a safe and accessible place in the lab and is used for the storage of instruments and chemicals for first aid.
Contents of a first aid kit and their uses
| Contents | Uses |
|---|---|
| 1. Pair of scissors | To cut adhesive tapes, bandages, and gauze |
| 2. Rolls of adhesive tape | To hold firmly into wounds bandages, gauze, and cotton wool |
| 3. Bandages and cotton wool | To clean and cover wounds |
| 4. Sterilised new razor blades | Used when treating new or old wounds |
| 5. Sterilised wound dressing | To clean and cover wounds |
| 6. Safety pin | To tighten clip bandages |
| 7. One jar of petroleum jelly | To apply on burns |
| 8. Iodine tincture | To clean fresh cuts and bruises |
| 9. Soap | To wash hands and wounds |
| 10. Antibiotic solution | To clean wounds |
Warning Signs
Warning signs are signs on the containers of chemicals as warnings about the danger of the contained chemical. There are six warning signs.
Explosives
These are substances that can explode. An explosion is a forceful rapid reaction which involves the throwing off of particles at high speeds.
The sign means that it is dangerous to keep explosives in glass containers.
Oxidant
This is a chemical or substance that helps a burning substance to burn faster.
Oxidising agents make a small fire become bigger. Heating a mixture of an organic material with an oxidising agent may cause explosion. For example, heating potassium permanganate with sawdust.
Flammable
These substances catch fire easily. They should not be kept near open flames. If heated, an electric heater should be used.
Corrosive
These substances burn skin as well as corrode floors and desktops.
If by accident, a corrosive substance comes into contact with your skin, go to the sink and wash your skin with a lot of water. Examples include concentrated mineral acids like HCl and HNO3, and concentrated alkalis like NaOH and KOH.
Toxic
These are very poisonous and can cause death immediately after use or after a few days. They should not be allowed to come into contact with you.
If you come into contact with such a chemical accidentally, wash it away with a lot of water.
Harmful/Irritant
Harmful substances may cause illness or endanger your health. They won’t kill instantly but they are lethal. Irritating substances cause pain in eyes or on your skin and can endanger your health if you are in contact with them for too long.
They should be handled according to the stipulated instructions.
Warning Signs in Daily Life
Use warning signs in daily life
Activity 1
Use warning signs in daily life
Basic Principles of Science Investigation
The Concept of Scientific Investigation
Scientific investigation refers to the step-by-step procedures and methods employed in carrying out scientific research.
Steps of Scientific Investigation
There are six different scientific steps:
- Identification of a problem: This is the first step where a problem is recognised. It provides explanations to the day-to-day questions which we come across in our lives. For example, it is observed that despite adequate feeding, vaccination, treatment, and spacious rooms, hens lay fewer eggs each day. What is the cause of the fewer number of eggs?
- Formulation of hypothesis: A hypothesis is an intelligent guess or a tentative explanation for the observation made. Using the example of a few eggs laid by hens per day, the hypothesis could be: a smaller number of eggs are laid because of unusually high temperature in the room. To prove this hypothesis, an experiment has to be carried out.
- Experimentation: The experiment involves a series of investigations intended to discover relationships or certain facts that may lead to the acceptance, rejection, or modification of a hypothesis. The first step in an experiment is to construct a plan of investigation.
- Observation and data recording: After setting up the experiment, a researcher makes careful observations using their sense organs and records all events that are considered relevant.
- Interpretation of data: Once a researcher has collected data, they should try to explain the meaning of the experiment. This is an attempt to interpret the data. The data may be presented in the form of a table, bar chart, histogram, or graph.
- Conclusion: This is either confirmation or rejection of the hypothesis.
A Theory
A theory is a set of scientific assumptions consistent with one another and supported by evidence but not fully proved (it is a hypothesis with more evidence).
Fact
A fact is a proved theory supported by evidence.
Hypothesis → Theory → Fact
Scientific Investigation Methods in Solving Problems
Use the scientific investigation methods in solving problems
Activity 2
Use the scientific investigation methods in solving problems
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