The heart and blood vessels (veins and arteries) make up the circulatory system. The heart pumps blood that carries oxygen and nutrients to all parts of the body. The heart is the size of a fist and acts like a pump to circulate blood. Tell your carschoolers to put their hands over the center of their chest to feel their heart pumping (beating).
Veins and arteries are tubes of varying sizes that act like a highway system in the body, transporting blood to all body parts. The heart pumps blood through the lungs where it collects oxygen and then heads out through the arteries to deliver the oxygen-rich blood to the body. When the blood has delivered the oxygen, it is pumped back to the heart and lungs through veins to get more. When blood is rich with oxygen it is red. When it has little oxygen, it is blue. That’s why veins are blue in color; they are returning oxygen-depleted blood to the heart and lungs.
Have your carschoolers look at the inside of their wrists to find their own circulating highways. They should be able to see some blue blood vessels near the surface of their skin.
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