Individual plants the children grow are a way to both interact with and observe the entire life cycle for second-graders. Each child can use a recycled container like a pint milk carton, Styrofoam cup or the bottom 1/3 of a 2-liter soda bottle. The children can put the plant medium in the container, add the seed and water, then record the growth. A study plan that includes the parts of a seed, the stages of growth and the entire plant cycle through to flower or fruit and re-seeding can be used as the seedlings germinate in class. The children can then take the plant home to complete the growth cycle when the lesson is finished.
An aquarium of polliwogs is a live visual aid for this lesson about the frog life cycle. Lesson materials include a printout of the frog life cycle in which the children color and place the animals in the correct order. The aquarium where the polliwogs grow is a research station, and each day the children can record growth changes in a science journal as they observe the polliwogs. Other activities can be observing an adult frog if it is possible to bring one to the classroom, or a visit to a local pond if one is nearby and accessible. If not, slides or other visuals can demonstrate the adult frogs as the children compare them to the polliwogs in class. When the polliwogs reach an older stage, they are released into the wild.
Comparing the life cycles of different animals creates a learning experience that displays how the animals follow a similar pattern even in the differences between species. Work sheets that cover the life cycle of a frog, butterfly and deer compare amphibian, insect and mammal. As the class discusses these cycles, the teacher can display visual aids to show the different stages of the cycle. As an active part of the lessons, children draw on a plain paper plate, sectioned into four quarters, the life cycle of one of the animals they have studied. A second plate has 1/4 cut away and is attached to the first plate as a viewer, so the children can turn it to display the cycles they have drawn.
Watching a butterfly life cycle live in class is a common lesson that enthralls children with the discovery process as the butterfly changes. A caterpillar can be placed in a large terrarium with plant materials. Caterpillars for science lessons are readily available for order on the Internet, or can be collected outside. A lid is placed on the terrarium, and the children observe the stages of the caterpillar creating its cocoon, then coming out as a butterfly to be released. A lesson plan includes the live research station as well as drawing and discussing the entire life cycle.