Practise investigating breathing rate, exercise and carbon dioxide release using indicators, graphs, percentage change and experimental critique.
A scientist investigates the effect of exercise on breathing rate.
She measures the breathing rate in breaths per minute of two people, P and Q , every 5 minutes for 30 minutes.
This is her method.
- measure their breathing rate every 5 minutes while they exercise for 20 minutes
- measure their breathing rate every 5 minutes for a further 10 minutes while they recover from the exercise
The table shows her results.
Plot a line graph of the results for person P and person Q . Use a ruler to join your points with straight lines.
(6)
Explain the change in breathing rate during exercise.
The time taken to recover from exercise is often a good measure of fitness.
The scientist concluded that person P is much fitter than person Q .
Comment on the validity of this conclusion.