practical 9

• release of carbon dioxide

  1. Pour some lime water into a boiling tube.
  2. Using a straw, breathe air into the lime water.
  3. Note the change in the limewater. Lime water turning cloudy indicates the presence ofcarbon dioxide.
• effect of exercise

  1. Measure and record the breathing rate (number of breaths per minute) of the participant at rest.
  2. Carry out a specific exercise (eg. running/jumping) for a fixed period of time eg.1 minute.
  3. Measure the breathing rate of the participant again.