1. Breath Out! L/O ;- To know and understand the difference between inhaled and exhaled air

3. Breathing Movements of the ribs, rib muscles and diaphragm allow air into and out of the lungs: this is called breathing or ventilation When we breathe in, we inhale When we breathe out, we exhale Air passes between the lungs and the outside of the body through the trachea The trachea divides into two bronchi, with one bronchus for each lung Each bronchus divides further in the lungs into smaller tubes called bronchioles At the end of each bronchiole, there is a group of tiny air sacs called alveoli

4. Inhalation (breathing in)

5. Exhalation (breathing out)

6. Get 1 boiling tube, and fill it 1/3 of the way up with limewater Using a delivery tube, exhale down the tube into this limewater (limewater goes cloudy in the presence of CO 2 ) With a cold mirror breathe onto it (you will notice a liquid condenses on it) - using cobalt chloride paper test to see if this is water (cobalt chloride goes from blue to pink in the presence of water) What do you think the differences between inhaled and exhaled air would be? How could you test for these differences?

7. Differences Inhaled & Exhaled Air inhaled air nitrogen (78%) oxygen (21%) carbon dioxide (0.04%) other exhaled air nitrogen (78%) oxygen (17%) carbon dioxide (4%) other Exhaled air contains less O 2, but much more CO 2

8. The reason we exhale less oxygen but much more carbon dioxide is because of aerobic respiration: - From digestive system From breathing system useful! Waste product exhaled carbon dioxide glucose oxygen water energy

9. So how big are you lungs? Can you see any patterns? What do you think affects lung volume?