Kindergarten topics emerge from the interest of the children. High-interest topics revolve around exploring the natural world. We divide science for grades 1-4 into subjects that roughly correspond to the periods of history the children are studying. As first grade studies the Ancients, it learns about the things the Ancients could see— animal life, the human body, plants— biology. Similarly, second grade studies astronomy and earth science, third grade explores basic chemistry and fourth grade introduces basic physics.