|Model heart (no blood in it at the moment)|
This is the model heart. The 4 bottles are the heart chambers, the clips are the valves. Pipes (available in Bunnings DIY) represent the veins and arteries. Basically you put red (oxygenated) blood into one top chamber, and blue (oxygen poor) blood into the other. Open the valves and the blood moves to the next chambers. Close the valves and pump (squeeze) the full chambers and the blood is pumped out of the heart again and off either to the lungs or to other parts of the body. Sounds easy - imagine a kitchen and mum soaked in red and blue food colouring.
This is our lung model, our main problem was finding a balloon big enough to make the diaphragm (purple). The red balloon is the lung and the straw the windpipe. Pull the diaphragm down and the lungs inflate.