biology paper 2 practicals

• 1. Work with a partner.
  2. Person A holds out their hand with a gap between their thumb and first finger.
  3. Person B holds the ruler with the zero at the top of person A's thumb.
  4. Person B drops the ruler without telling Person A and they must catch it.
  5. The number level with the top of person A's thumb is recorded in a suitable table. Repeat this five times.
  6. Swap places, and record another five attempts.
  7. You can use the conversion table to help convert your ruler measurements into reaction time or just record the catch distance in centimetres.
• Experiment setup

  1. Put cotton wool into three petri dishes

  2. Add the same volume of water to each dish

  3. Add ten seeds to each dish

  4. Place them in a warm place where they won't be disturbed
• Seed germination

  1. Allow the seeds to germinate

  2. Add more water if the cotton wool dries out
• Seed selection

  1. Ensure the petri dishes each contain the same number of seeds

  2. Remove any extra seeds if necessary
• Lighting conditions

  1. One petri dish will sit in full light on a windowsill

  2. The second will be in a dark cupboard

  3. The final dish will be placed in partial light
• Data collection

  1. Every day for one week, measure the height of each seedling

  2. Record the results in a table
• Mean

  The average of the seedling heights in each petri dish
• Comparing mean heights

  In the three different lighting conditions
• 1. choose a starting point on the school field in an area where the grass is often cut
  2. use random numbers to generate a set of coordinates to place your first quadrat
  3. count the number of different plant species within this quadrat (the species richness)
  4. return to your starting position and repeat steps two and three a further 14 times using different random numbers
  5. repeat steps one to four for a part of the school field which the grass is infrequently cut
  6. compare your results by calculating a mean for each location
• 1. Place 20 cm3 of fresh milk into three beakers
  2. Decide the three temperatures you will investigate. Write these onto the sides of the beakers. They may be 5, 20 and 35°C.
  3. Use universal indicator paper or solution to determine the pH of the milk in the three beakers
  4. Cover each beaker in cling film and incubate at the appropriate temperature
  5. Use universal indicator paper or solution to determine the pH of the milk in the three beakers after 24, 48 and 72 hours