diagram of the human heart which I am using for a classroom display. Left ventricle and right ventricle contain sealed food bags with paint for pupils to feel and squeeze, representing oxygenated and deoxygenated blood. Really pleased with the result.
Heart Pump DIY. With every heartbeat, muscles in your heart contract and squeeze the chambers (or open spaces) within your heart. This squeeze pushes the blood into the chamber and moves it out of your heart and into your arteries. In your balloon heart, the water "blood" gets pushed up and out the straw "artery." Your heart does this an average of 70 times every minute, pushing your blood all the way around your body and back to your heart again!