Flowering bulb plants grow at different rates. Comparisons between individual plants or between types of plants illustrate different patterns of growth. For example, amaryllis plants grow taller rapidly when in bud, but this increase in height slows as the flower begins to bloom. Primary students usually look for qualitative patterns, but quantitative studies are also possible.

During these lessons, students are introduced to qualitative studies of change over time. First, they compare plants directly. They are shown paper strips that serve as records of plant height on each measurement day, and are asked to make comparisons between heights on successive days. The students come to see that the amount of growth between days is the difference in lengths of the paper strips. Children notice how the paper strip displays model growth patterns for the plants-some plants grow quickly at the beginning of the life cycle, others grow more slowly at first, but more quickly later on. We move to quantitative studies of growth rate in the upper elementary grades.