Artificial Lungs

Things you need

1. plastic bottle 
2. two balloons                                    
3. straws

Method

cut the bottom of the bottle .make a hole at the center of the other side send a straw through that hole make sure that air cant go through it ,fix a small balloon at the other end .fix a piece of balloon at the open end as a diapram..When the diapram is pulled air is drawn to the balloon and it expands.