6.
Describe an activity to show that exhaled air contains carbon dioxide.
7. Describe the changes that take place (i) around the rib cage (ii) diaphragm
(iii) chest cavity, during inspiration. State the effect of these changes.
Answers
Answer:
6. Take a test tube fill it with freshly prepared lime water take a straw dip it inside lime water and then exhale you will find that the lime water turns its colour to white like milky colour. This shows that the air which we exhale is carbon dioxide.
7. the Rib cage assist in breathing by the use of intercostal muscles present between each rib. the external intercostal muscles raise the Rib cage which assists in inspiration.
during inspiration the diaphragm contracts and move downwards. this activity expands the lungs reducing the pressure inside the lungs causing air to move into it.
the diagram the Rib cage and the lungs from the chest cavity when we breathe in. the chest cavity expands and move downwards which causes the lungs to expand as well as intercostal muscles expand the chest cavity. this helps in inspiration