The teacher leads a discussion in which students identify the physical needs of animals, and then speculate on the needs of plants. With guidance from the teacher, the students then help design an experiment that can take place in the classroom to test whether or not plants need light and water in order to grow. Sunflower seeds are planted in plastic cups, and once germinated, are exposed to different conditions. In particular, within the classroom setting it is easy to test for the effects of light versus darkness, and watered versus non-watered conditions. During exposure of the plants to these different conditions, students measure growth of the seedlings every few days using non-standard measurement. After a few weeks, they compare the growth of plants exposed to the different conditions, and make pictorial bar graphs that demonstrate these comparisons.