A young boy learns about his heart through the step-by-step construction of a simple circulatory system. He learns how his heart pumps, what blood and blood vessels do, how they do it, and some of the ways to help his heart stay healthy.
1963
1953
—
2017
1947
2018
1998
2016
2011
2019
1972
1991
2025
1965
1966
1967