B1 practicals

• Microscopy

  1. Peel off an epidermal layer on the onion

  2. Mount onto the microscope slide with a drop of water using a pipette

  3. Add 2 drops of iodine solution to stain the cells

  4. Place the cover slip on slowly making sure no air bubbles are trapped

  5. Rotate the objective lenses so that the low power is in line with the stage

  6. Turn the course focus so that the stage is as close to the objective lens as possible

  7. Place the microscope slide in the center of the stage

  8. Focus the slide

  9. Rotate the objectives so that the high power objective is in line with the stage
• Osmosis experiment

  1. Use a cork borer to cut 5 potato cylinders

  2. Trim the cylinders to be the same length

  3. Measure and record the length and mass of each cylinder

  4. Measure equal quantities of the sugar solutions and add to the boiling tubes, labelling them

  5. Add a potato cylinder to each tube

  6. Leave the cylinders overnight in a test tube rack

  7. Remove cylinders and blotch

  8. Measure length and mass of each cylinder and calculate the percentage change
• What is the aim of the osmosis practical?

  To investigate the effect of a range of concentrations of salt or sugar solution on the mass of plant tissue
• Food test experiment

  1. Take the food sample and grind it with distilled water using a mortar and pestle
  2. add the paste into a beaker and add more distilled water. Stir the solution
  3. Filter the solution to remove suspended food particles
• Photosynthesis practical

  1. Take a boiling tube and place it 10 cm away from an LED light source
  2. fill the boiling tube with sodium hydrogen carbonate solution.
  3. put a piece of pondweed into the boiling tube with the cut and at the top
  4. leave this for five minutes to acclimatise to the conditions in the boiling tube
  5. start a stopwatch and count the number of bubbles produced in one minute
  6. repeat this two more times to calculate mean
  7. repeat the whole experiment, increasing the distance of the boiling tube by 10 cm each time