Required practicals

• B4- the rate of photosynthesis

  1. A source of white light is placed at a specific distance from the pond weed
  2. pondweed is left to photosynthesise, oxygen will be released and will collect in the capillary tube
  3. the syringe is used to draw the gas bubble in the tube along side the ruler and the length is measured
  4. the experiment is repeated with the light source at different distances and the mean volume of oxygen is calculated
• B1- microscopy

  1. prepare your slide
  2. add water to the middle
  3. get an onion and use tweezers to peel epidermal tissue
  4. place the tissue on the slide
  5. add a drop of iodine solution, this highlights the object
  6. place a cover slip on top
• B1- microscopy

  1. clip your slide on the stage
  2. select the lowest objective lens
  3. use the course adjuster to move the stage up
  4. look in the eyepiece and adjust the stage until it focuses with the fine adjuster
  5. if you need to see it with greater magnification swap to a high power objective lens
  6. draw your results
• B1- culturing microorganisms

  1. prepare a plate of agar jelly with a culture if bacteria
  2. divide the plate into three sections
  3. put different antiseptics/ antibiotics on paper discs and place in each section
  4. leave the plate for at least last 48 hours at 25 degrees
  5. measure the area of the clear zone and compare the effectivness
• B1-osmosis

  1. cut 5 equal potatoes into cylinders
  2. measure the length and mass of each potato
  3. place each potato in 5 different concentrations of solution e.g pure water and very concentrated sugar solution
  4. leave them for atleast 24 hours
  5. dry the potato’s with a paper towel and measure the masses again wit’s a balance
  6. if the cylinders have drawn water by osmosis they’ll have increases in mass
  7. reduce the affect of errors by calculating a mean percentage change