Practical: Breathing In Humans

Question 1

Outline the procedure to investigate the release of carbon dioxide through breathing.

Answer 1

Use a straw to breathe out into a boiling tube containing lime water. Note the change in the lime water.

Question 2

What is observed when carbon dioxide is mixed with lime water?

Answer 2

Lime water turns milky.

Question 3

Outline the procedure to find the effect of exercise on breathing rate.

Answer 3

Measure the breathing rate (number of breaths per minute) of the participant at rest.
Carry out exercise for a minute. Measure the breathing rate again and compare.