To capture students' beginning knowledge of seed structure and to provide a record of their initial ideas about seeds. To assess students' ideas about seeds at the end of the unit.

Children are given blank paper and asked to create a drawing of a seed and what they think the seed looks like on the inside. They are encouraged to add labels to their diagrams that might help someone else understand their drawing. No teaching or class discussions precede this task, so the drawings are true "snapshots" of student thinking at the start of the unit.

This task is repeated at the conclusion of the unit as one way of documenting how students' understanding of seed structures has grown.

The early pre-assessment drawing show that most students are unfamiliar with the internal structure of seeds. Their ideas about what might be inside a seed seem to draw upon other science ideas they have previously encountered. Many students create diagrams and choose terminology that could be used to describe the layers of the earth, while other imagine that the inside of a see has features in common with the human circulatory system.

The drawing that resemble cross-sections of the earth have distinct layers. The first layer is called the "shell," "hard cover" and "crust." Several students include an "outer core" and "inner core." Many students seem to think that the primary role of these multiple layers is protection. One girls labels the layers as "shields," and another student labels the central part of her seed as the "place that keeps the beginner warm." The area at the center of these layer is described by different student as "the black seed that turns into the flower," the "core that stores all the vitamins so the seed can be healthy," "where the growth starts" and the place for "growth." The drawings that seem to be based on a circulatory model show a central "heart" or a system of "veins." Water and roots figure prominently in the thinking of students who do not draw concentric layers inside their seed. Several drawings show the inside of a seed as a tangle of roots.

Although these early drawings and labels indicate that students may have some concept of an embryo, only one student actually labels an " embryo ."

The final drawings completed after observing seeds in the germination bags and opening soaked seeds are much more accurate in terms of a seed's internal structure. Only one-eighth of the first seed drawings show an embryo or "baby plant" of some kind, but 87% of the later drawings include an embryo of baby plant. It is important to note that the text added to the drawings indicates a range in student understanding of the term embryo . One student writes that "an embryo is a little seed in a bigger seed" while another student explains that "an embryo is a baby plant living inside a seed before it pops out to be a seedling." Approximately one-third of the early seed drawings make reference to some kind of hard outer covering or "shell," but none of the students use the term seed coat on these initial diagrams. In comparison, 71% of the later seed drawings included a protective outer layer. Half of these student used the term "seed coat" to label their drawing, whereas half used another name such as "shell," "skin" or "cover." While only two students made any mention at all of food on their early drawings, 85% of the later drawings indicate that food is found inside a seed. In many of the drawings, food makes up most of the seed. Students included comments such as, "There's food in the whole seed" or "I learned that there was mainly food in a seed." Many students explained, "The food helps the baby plant grow."