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Biology Unit 5
Topic 7: Run for your life
14. Describe how to investigate the effects of exercise
on tidal volume and breathing rate using data from
To find the vital capacity of a person's lungs, or to measure their inspiratory or expiratory reserves,
we can use a spirometer.
The subject of the experiment breathes in and out of the airtight chamber making it move up
and down, until all the oxygen is used up.
Airtight chamber a lid floating on water. The chamber is filled with oxygen at the beginning
of the experiment. Attached to the lid of the chamber is an arm with a pen on the end.
The pen draws onto a revolving drum giving a trace as the lid moves up and down.
A canister of soda lime removes carbon dioxide from the exhaled air. This is important
because carbon dioxide levels affect the rate of breathing and therefore if CO was allowed
to accumulate, the investigation would be affected.
Text Book: p.159