B7

• How many practical experiments are you required to do?

  At least 8
• What are the key safety precautions to follow in the lab?

  • Know safety precautions before experiments
  • Wear sensible clothing and lab coat
  • Use safety goggles and gloves if needed
  • Keep flammable materials away from sources
  • Handle glassware carefully
• Why is it important to wear a lab coat in the lab?

  To protect your skin and clothing
• What should you do if you are using hazardous chemicals?

  Follow teacher's instructions carefully
• What ethical considerations should be taken when conducting experiments involving organisms?

  • Treat organisms safely and ethically
  • Handle animals humanely
  • Return wild animals to their habitat
  • Care for lab animals properly
  • Ensure voluntary participation of human subjects
• What is the purpose of random sampling in experiments?

  To avoid biased results
• How can you ensure random sampling in a field study?

  1. Divide the field into a grid
  2. Label the grid with numbers/letters
  3. Use a random number generator for coordinates
  4. Sample at the selected coordinates
• What is the formula for the area of a rectangle?

  Area = length × width
• If a field measures 30 m by 55 m, what is its area?

  $1650 \text{ m}^2$
• What are the steps to measure the area of a complex shape?

  1. Take accurate measurements of dimensions
  2. Compare to a simpler shape
  3. Calculate the area using appropriate formula
• What should you do before weighing a solid substance?

  Set the balance to zero
• How should you measure time in an experiment?

  Use a stopwatch measuring to 0.1 s
• What is the correct way to read a thermometer?

  At eye level with the bulb submerged
• What are the methods to measure the volume of a liquid?

  • Use a measuring cylinder
  • Use a pipette for transfers
  • Read from the bottom of the meniscus
• What is the best method to measure gas volume accurately?

  Use a gas syringe
• How do you measure pH in a solution?

  Use indicators or pH meters
• What are the steps to measure your pulse?

  1. Find pulse on wrist
  2. Count beats in 15 seconds
  3. Multiply by four for bpm
• What are the safety precautions for using Bunsen burners?

  • Use on a heat-proof mat
  • Adjust flame for visibility
  • Hold vessels with tongs
  • Point openings away from yourself
• How do you use an electric water bath?

  1. Set desired temperature
  2. Monitor with a thermometer
  3. Submerge boiling tube properly
  4. Ensure even heating
• What are the guidelines for drawing observations under a microscope?

  • Use a sharp pencil
  • Draw clear, unbroken lines
  • No coloring or shading
  • Include title and magnification
  • Label important features
• How does a colorimeter work?

  1. Light passes through a solution
  2. Measures light absorption
  3. Higher absorbance indicates darker color
  4. Useful for tracking color changes
• What is continuous sampling in experiments?

  • Taking multiple samples at intervals
  • Allows observation of changes over time
  • Improves accuracy with large sample sizes
• What should you do if you want to measure the absorbance of a solution?

  Use a colorimeter
• Why is it important to use a data logger in experiments?

  It improves accuracy and sample size
• What are the benefits of using a data logger?

  • Continuous data collection
  • Improved accuracy
  • Ability to process data easily
• What should you consider when working in a lab?

  Safety, ethics, and sampling methods
• Why is it important to sample organisms at random sites?

  To ensure unbiased and representative results
• What units can length be measured in?

  mm, cm, m
• Why is it more accurate to measure a potato cylinder to the nearest cm?

  Smaller units provide a higher degree of accuracy
• How would you measure the length of a leaf?

  In millimetres for better accuracy
• What equipment is best for measuring larger distances?

  A metre rule or a tape measure
• What are the steps to measure the area of a rectangular field?

  1. Measure length and width with a tape measure.
  2. Record readings in metres.
  3. Calculate area using: Area = length x width.
• What is the formula for the area of a rectangle?

  Area = length x width
• What is the area of a field measuring 30 m by 55 m?

  $1650 \text{ m}^2$
• What is the formula for the area of a triangle?

  Area = ½ x base x height
• What is the formula for the area of a circle?

  Area = πr²
• How do you weigh a solid substance accurately?

  Use a balance and zero the container
• What is the best tool for timing experiments?

  A stopwatch measuring to the nearest 0.1 s
• Why is it important to start and stop the stopwatch at the right time?

  To ensure accurate timing of reactions
• How should you measure the temperature of a solution?

  Ensure the thermometer bulb is submerged